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• Building a SOA/BPM/BAM Cluster Part I &ndash; Preparing the Environment

  - by antony.reynolds

  An increasing number of customers are using SOA Suite in a cluster configuration, I might hazard to say that the majority of production deployments are now using SOA clusters.  So I thought it may be useful to detail the steps in building an 11g cluster and explain a little about why things are done the way they are. In this series of posts I will explain how to build a SOA/BPM cluster using the Enterprise Deployment Guide. This post will explain the setting required to prepare the cluster for installation and configuration. Software Required The following software is required for an 11.1.1.3 SOA/BPM install. Software Version Notes Oracle Database Certified databases are listed here SOA & BPM Suites require a working database installation. Repository Creation Utility (RCU) 11.1.1.3 If upgrading an 11.1.1.2 repository then a separate script is available. Web Tier Utilities 11.1.1.3 Provides Web Server, 11.1.1.3 is an upgrade to 11.1.1.2, so 11.1.1.2 must be installed first. Web Tier Utilities 11.1.1.3 Web Server, 11.1.1.3 Patch.  You can use the 11.1.1.2 version without problems. Oracle WebLogic Server 11gR1 10.3.3 This is the host platform for 11.1.1.3 SOA/BPM Suites. SOA Suite 11.1.1.2 SOA Suite 11.1.1.3 is an upgrade to 11.1.1.2, so 11.1.1.2 must be installed first. SOA Suite 11.1.1.3 SOA Suite 11.1.1.3 patch, requires 11.1.12 to have been installed. My installation was performed on Oracle Enterprise Linux 5.4 64-bit. Database I will not cover setting up the database in this series other than to identify the database requirements.  If setting up a SOA cluster then ideally we would also be using a RAC database.  I assume that this is running on separate machines to the SOA cluster.  Section 2.1, “Database”, of the EDG covers the database configuration in detail. Settings The database should have processes set to at least 400 if running SOA/BPM and BAM. alter system set processes=400 scope=spfile Run RCU The Repository Creation Utility creates the necessary database tables for the SOA Suite.  The RCU can be run from any machine that can access the target database.  In 11g the RCU creates a number of pre-defined users and schema with a user defiend prefix.  This allows you to have multiple 11g installations in the same database. After running the RCU you need to grant some additional privileges to the soainfra user.  The soainfra user should have privileges on the transaction tables. grant select on sys.dba_pending_transactions to prefix_soainfra Grant force any transaction to prefix_soainfra Machines The cluster will be built on the following machines. EDG Name is the name used for this machine in the EDG. Notes are a description of the purpose of the machine. EDG Name Notes LB External load balancer to distribute load across and failover between web servers. WEBHOST1 Hosts a web server. WEBHOST2 Hosts a web server. SOAHOST1 Hosts SOA components. SOAHOST2 Hosts SOA components. BAMHOST1 Hosts BAM components. BAMHOST2 Hosts BAM components. Note that it is possible to collapse the BAM servers so that they run on the same machines as the SOA servers. In this case BAMHOST1 and SOAHOST1 would be the same, as would BAMHOST2 and SOAHOST2. The cluster may include more than 2 servers and in this case we add SOAHOST3, SOAHOST4 etc as needed. My cluster has WEBHOST1, SOAHOST1 and BAMHOST1 all running on a single machine. Software Components The cluster will use the following software components. EDG Name is the name used for this machine in the EDG. Type is the type of component, generally a WebLogic component. Notes are a description of the purpose of the component. EDG Name Type Notes AdminServer Admin Server Domain Admin Server WLS_WSM1 Managed Server Web Services Manager Policy Manager Server WLS_WSM2 Managed Server Web Services Manager Policy Manager Server WLS_SOA1 Managed Server SOA/BPM Managed Server WLS_SOA2 Managed Server SOA/BPM Managed Server WLS_BAM1 Managed Server BAM Managed Server running Active Data Cache WLS_BAM2 Managed Server BAM Manager Server without Active Data Cache   Node Manager Will run on all hosts with WLS servers OHS1 Web Server Oracle HTTP Server OHS2 Web Server Oracle HTTP Server LB Load Balancer Load Balancer, not part of SOA Suite The above assumes a 2 node cluster. Network Configuration The SOA cluster requires an extensive amount of network configuration.  I would recommend assigning a private sub-net (internal IP addresses such as 10.x.x.x, 192.168.x.x or 172.168.x.x) to the cluster for use by addresses that only need to be accessible to the Load Balancer or other cluster members.  Section 2.2, "Network", of the EDG covers the network configuration in detail. EDG Name is the hostname used in the EDG. IP Name is the IP address name used in the EDG. Type is the type of IP address: Fixed is fixed to a single machine. Floating is assigned to one of several machines to allow for server migration. Virtual is assigned to a load balancer and used to distribute load across several machines. Host is the host where this IP address is active.  Note for floating IP addresses a range of hosts is given. Bound By identifies which software component will use this IP address. Scope shows where this IP address needs to be resolved. Cluster scope addresses only have to be resolvable by machines in the cluster, i.e. the machines listed in the previous section.  These addresses are only used for inter-cluster communication or for access by the load balancer. Internal scope addresses Notes are comments on why that type of IP is used. EDG Name IP Name Type Host Bound By Scope Notes ADMINVHN VIP1 Floating SOAHOST1-SOAHOSTn AdminServer Cluster Admin server, must be able to migrate between SOA server machines. SOAHOST1 IP1 Fixed SOAHOST1 NodeManager, WLS_WSM1 Cluster WSM Server 1 does not require server migration. SOAHOST2 IP2 Fixed SOAHOST1 NodeManager, WLS_WSM2 Cluster WSM Server 2 does not require server migration SOAHOST1VHN VIP2 Floating SOAHOST1-SOAHOSTn WLS_SOA1 Cluster SOA server 1, must be able to migrate between SOA server machines SOAHOST2VHN VIP3 Floating SOAHOST1-SOAHOSTn WLS_SOA2 Cluster SOA server 2, must be able to migrate between SOA server machines BAMHOST1 IP4 Fixed BAMHOST1 NodeManager Cluster   BAMHOST1VHN VIP4 Floating BAMHOST1-BAMHOSTn WLS_BAM1 Cluster BAM server 1, must be able to migrate between BAM server machines BAMHOST2 IP3 Fixed BAMHOST2 NodeManager, WLS_BAM2 Cluster BAM server 2 does not require server migration WEBHOST1 IP5 Fixed WEBHOST1 OHS1 Cluster   WEBHOST2 IP6 Fixed WEBHOST2 OHS2 Cluster   soa.mycompany.com VIP5 Virtual LB LB Public External access point to SOA cluster. admin.mycompany.com VIP6 Virtual LB LB Internal Internal access to WLS console and EM soainternal.mycompany.com VIP7 Virtual LB LB Internal Internal access point to SOA cluster Floating IP addresses are IP addresses that may be re-assigned between machines in the cluster.  For example in the event of failure of SOAHOST1 then WLS_SOA1 will need to be migrated to another server.  In this case VIP2 (SOAHOST1VHN) will need to be activated on the new target machine.  Once set up the node manager will manage registration and removal of the floating IP addresses with the exception of the AdminServer floating IP address. Note that if the BAMHOSTs and SOAHOSTs are the same machine then you can obviously share the hostname and fixed IP addresses, but you still need separate floating IP addresses for the different managed servers.  The hostnames don’t have to be the ones given in the EDG, but they must be distinct in the same way as the ETC names are distinct.  If the type is a fixed IP then if the addresses are the same you can use the same hostname, for example if you collapse the soahost1, bamhost1 and webhost1 onto a single machine then you could refer to them all as HOST1 and give them the same IP address, however SOAHOST1VHN can never be the same as BAMHOST1VHN because these are floating IP addresses. Notes on DNS IP addresses that are of scope “Cluster” just need to be in the hosts file (/etc/hosts on Linux, C:\Windows\System32\drivers\etc\hosts on Windows) of all the machines in the cluster and the load balancer.  IP addresses that are of scope “Internal” need to be available on the internal DNS servers, whilst IP addresses of scope “Public” need to be available on external and internal DNS servers. Shared File System At a minimum the cluster needs shared storage for the domain configuration, XA transaction logs and JMS file stores.  It is also possible to place the software itself on a shared server.  I strongly recommend that all machines have the same file structure for their SOA installation otherwise you will experience pain!  Section 2.3, "Shared Storage and Recommended Directory Structure", of the EDG covers the shared storage recommendations in detail. The following shorthand is used for locations: ORACLE_BASE is the root of the file system used for software and configuration files. MW_HOME is the location used by the installed SOA/BPM Suite installation.  This is also used by the web server installation.  In my installation it is set to <ORACLE_BASE>/SOA11gPS2. ORACLE_HOME is the location of the Oracle SOA components or the Oracle Web components.  This directory is installed under the the MW_HOME but the name is decided by the user at installation, default values are Oracle_SOA1 and Oracle_Web1.  In my installation they are set to <MW_HOME>/Oracle_SOA and <MW_HOME>/Oracle _WEB. ORACLE_COMMON_HOME is the location of the common components and is located under the MW_HOME directory.  This is always <MW_HOME>/oracle_common. ORACLE_INSTANCE is used by the Oracle HTTP Server and/or Oracle Web Cache.  It is recommended to create it under <ORACLE_BASE>/admin.  In my installation they are set to <ORACLE_BASE>/admin/Web1, <ORACLE_BASE>/admin/Web2 and <ORACLE_BASE>/admin/WC1. WL_HOME is the WebLogic server home and is always found at <MW_HOME>/wlserver_10.3. Key file locations are shown below. Directory Notes <ORACLE_BASE>/admin/domain_name/aserver/domain_name Shared location for domain.  Used to allow admin server to manually fail over between machines.  When creating domain_name provide the aserver directory as the location for the domain. In my install this is <ORACLE_BASE>/admin/aserver/soa_domain as I only have one domain on the box. <ORACLE_BASE>/admin/domain_name/aserver/applications Shared location for deployed applications.  Needs to be provided when creating the domain. In my install this is <ORACLE_BASE>/admin/aserver/applications as I only have one domain on the box. <ORACLE_BASE>/admin/domain_name/mserver/domain_name Either unique location for each machine or can be shared between machines to simplify task of packing and unpacking domain.  This acts as the managed server configuration location.  Keeping it separate from Admin server helps to avoid problems with the managed servers messing up the Admin Server. In my install this is <ORACLE_BASE>/admin/mserver/soa_domain as I only have one domain on the box. <ORACLE_BASE>/admin/domain_name/mserver/applications Either unique location for each machine or can be shared between machines.  Holds deployed applications. In my install this is <ORACLE_BASE>/admin/mserver/applications as I only have one domain on the box. <ORACLE_BASE>/admin/domain_name/soa_cluster_name Shared directory to hold the following   dd – deployment descriptors   jms – shared JMS file stores   fadapter – shared file adapter co-ordination files   tlogs – shared transaction log files In my install this is <ORACLE_BASE>/admin/soa_cluster. <ORACLE_BASE>/admin/instance_name Local folder for web server (OHS) instance. In my install this is <ORACLE_BASE>/admin/web1 and <ORACLE_BASE>/admin/web2. I also have <ORACLE_BASE>/admin/wc1 for the Web Cache I use as a load balancer. <ORACLE_BASE>/product/fmw This can be a shared or local folder for the SOA/BPM Suite software.  I used a shared location so I only ran the installer once. In my install this is <ORACLE_BASE>/SOA11gPS2 All the shared files need to be put onto a shared storage media.  I am using NFS, but recommendation for production would be a SAN, with mirrored disks for resilience. Collapsing Environments To reduce the hardware requirements it is possible to collapse the BAMHOST, SOAHOST and WEBHOST machines onto a single physical machine.  This will require more memory but memory is a lot cheaper than additional machines.  For environments that require higher security then stay with a separate WEBHOST tier as per the EDG.  Similarly for high volume environments then keep a separate set of machines for BAM and/or Web tier as per the EDG. Notes on Dev Environments In a dev environment it is acceptable to use a a single node (non-RAC) database, but be aware that the config of the data sources is different (no need to use multi-data source in WLS).  Typically in a dev environment we will collapse the BAMHOST, SOAHOST and WEBHOST onto a single machine and use a software load balancer.  To test a cluster properly we will need at least 2 machines. For my test environment I used Oracle Web Cache as a load balancer.  I ran it on one of the SOA Suite machines and it load balanced across the Web Servers on both machines.  This was easy for me to set up and I could administer it from a web based console.

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• Why is USB-sticks so much slower than Solid State Drives?

  - by Jonas

  From what I understand, USB flash memory and Solid State Drives are based on similar technologies, NAND flash memory. But USB-sticks is usually quite slow with a read and write speed of 5-10MB per second while Solid State Drives usually is very fast, usually 100-570MB per second. Why are Solid State Drives so much faster than USB-sticks? And why isn't USB-sticks faster than 5-10MB per second? Is it simply that SSD-drives uses parallel access to the NAND flash memory or are there other reasons?

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• SQL database testing: How to capture state of my database for rollback.

  - by Rising Star

  I have a SQL server (MS SQL 2005) in my development environment. I have a suite of unit tests for some .net code that will connect to the database and perform some operations. If the code under test works correctly, then the database should be in the same (or similar) state to how it was before the tests. However, I would like to be able to roll back the database to its state from before the tests run. One way of doing this would be to programmatically use transactions to roll back each test operation, but this is difficult and cumbersome to program; it could easily lead to errors in the test code. I would like to be able to run my tests confidently knowing that if they destroy my tables, I can quickly restore them? What is a good way to save a snapshot of one of my databases with its tables so that I can easily restore the database to it's state from before the test?

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• Odd performance with C# Asynchronous server socket

  - by The.Anti.9

  I'm working on a web server in C# and I have it running on Asynchronous socket calls. The weird thing is that for some reason, when you start loading pages, the 3rd request is where the browser won't connect. It just keeps saying "Connecting..." and doesn't ever stop. If I hit stop. and then refresh, it will load again, but if I try another time after that it does the thing where it doesn't load again. And it continues in that cycle. I'm not really sure what is making it do that. The code is kind of hacked together from a couple of examples and some old code I had. Any miscellaneous tips would be helpful as well. Heres my little Listener class that handles everything (pastied here. thought it might be easier to read this way) using System; using System.Collections.Generic; using System.Net; using System.Net.Sockets; using System.Text; using System.Threading; namespace irek.Server { public class Listener { private int port; private Socket server; private Byte[] data = new Byte[2048]; static ManualResetEvent allDone = new ManualResetEvent(false); public Listener(int _port) { port = _port; } public void Run() { server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); IPEndPoint iep = new IPEndPoint(IPAddress.Any, port); server.Bind(iep); Console.WriteLine("Server Initialized."); server.Listen(5); Console.WriteLine("Listening..."); while (true) { allDone.Reset(); server.BeginAccept(new AsyncCallback(AcceptCon), server); allDone.WaitOne(); } } private void AcceptCon(IAsyncResult iar) { allDone.Set(); Socket s = (Socket)iar.AsyncState; Socket s2 = s.EndAccept(iar); SocketStateObject state = new SocketStateObject(); state.workSocket = s2; s2.BeginReceive(state.buffer, 0, SocketStateObject.BUFFER_SIZE, 0, new AsyncCallback(Read), state); } private void Read(IAsyncResult iar) { try { SocketStateObject state = (SocketStateObject)iar.AsyncState; Socket s = state.workSocket; int read = s.EndReceive(iar); if (read > 0) { state.sb.Append(Encoding.ASCII.GetString(state.buffer, 0, read)); if (s.Available > 0) { s.BeginReceive(state.buffer, 0, SocketStateObject.BUFFER_SIZE, 0, new AsyncCallback(Read), state); return; } } if (state.sb.Length > 1) { string requestString = state.sb.ToString(); // HANDLE REQUEST HERE // Temporary response string resp = "<h1>It Works!</h1>"; string head = "HTTP/1.1 200 OK\r\nContent-Type: text/html;\r\nServer: irek\r\nContent-Length:"+resp.Length+"\r\n\r\n"; byte[] answer = Encoding.ASCII.GetBytes(head+resp); // end temp. state.workSocket.BeginSend(answer, 0, answer.Length, SocketFlags.None, new AsyncCallback(Send), state.workSocket); } } catch (Exception) { return; } } private void Send(IAsyncResult iar) { try { SocketStateObject state = (SocketStateObject)iar.AsyncState; int sent = state.workSocket.EndSend(iar); state.workSocket.Shutdown(SocketShutdown.Both); state.workSocket.Close(); } catch (Exception) { } return; } } } And my SocketStateObject: public class SocketStateObject { public Socket workSocket = null; public const int BUFFER_SIZE = 1024; public byte[] buffer = new byte[BUFFER_SIZE]; public StringBuilder sb = new StringBuilder(); }

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• What is a good java data structure for storing nested items (like cities in states)?

  - by anotherAlan

  I'm just getting started in Java and am looking for advice on a good way to store nested sets of data. For example, I'm interested in storing city population data that can be accessed by looking up the city in a given state. (Note: eventually, other data will be stored with each city as well, this is just the first attempt at getting started.) The current approach I'm using is to have a StateList Object which contains a HashMap that stores State Objects via a string key (i.e. HashMap<String, State>). Each State Object contains its own HashMap of City Objects keyed off the city name (i.e. HashMap<String, City>). A cut down version of what I've come up with looks like this: // TestPopulation.java public class TestPopulation { public static void main(String [] args) { // build the stateList Object StateList sl = new StateList(); // get a test state State stateAl = sl.getState("AL"); // make sure it's there. if(stateAl != null) { // add a city stateAl.addCity("Abbeville"); // now grab the city City cityAbbevilleAl = stateAl.getCity("Abbeville"); cityAbbevilleAl.setPopulation(2987); System.out.print("The city has a pop of: "); System.out.println(Integer.toString(cityAbbevilleAl.getPopulation())); } // otherwise, print an error else { System.out.println("That was an invalid state"); } } } // StateList.java import java.util.*; public class StateList { // define hash map to hold the states private HashMap<String, State> theStates = new HashMap<String, State>(); // setup constructor that loads the states public StateList() { String[] stateCodes = {"AL","AK","AZ","AR","CA","CO"}; // etc... for (String s : stateCodes) { State newState = new State(s); theStates.put(s, newState); } } // define method for getting a state public State getState(String stateCode) { if(theStates.containsKey(stateCode)) { return theStates.get(stateCode); } else { return null; } } } // State.java import java.util.*; public class State { // Setup the state code String stateCode; // HashMap for cities HashMap<String, City> cities = new HashMap<String, City>(); // define the constructor public State(String newStateCode) { System.out.println("Creating State: " + newStateCode); stateCode = newStateCode; } // define the method for adding a city public void addCity(String newCityName) { City newCityObj = new City(newCityName); cities.put(newCityName, newCityObj); } // define the method for getting a city public City getCity(String cityName) { if(cities.containsKey(cityName)) { return cities.get(cityName); } else { return null; } } } // City.java public class City { // Define the instance vars String cityName; int cityPop; // setup the constructor public City(String newCityName) { cityName = newCityName; System.out.println("Created City: " + newCityName); } public void setPopulation(int newPop) { cityPop = newPop; } public int getPopulation() { return cityPop; } } This is working for me, but I'm wondering if there are gotchas that I haven't run into, or if there are alternate/better ways to do the same thing. (P.S. I know that I need to add some more error checking in, but right now, I'm focused on trying to figure out a good data structure.) (NOTE: Edited to change setPop() and getPop() to setPopulation() and getPopulation() respectively to avoid confucsion)

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• I'm using a shared server, and as such Gmail marks my email as spam (all from headers are different from the same IP)

  - by chipperyman573

  I have a shared server, meaning many people share the same IP. When I send an email, the @website.com is different from someone else that shares the same IP with me, therefore Gmail marks it as spam. For example: My website's IP is 1.2.3.4. My website is mywebsite.com Person 2's website's IP is hosted by the same host, and as such their IP is 1.2.3.4 Person 2's website is person2.com. When they send an email, it gets sent from [email protected] When I send an email, it gets sent from [email protected] According to Gmail's spam thing: "Use the same address in the 'From:' header on every bulk mail you send." Again, the only similarities between our websites is the IP. However, this causes Gmail to mark both our mail as spam. Is there a way to sort this out with Gmail?

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• Multiplayer Network Game - Interpolation and Frame Rate

  - by J.C.

  Consider the following scenario: Let's say, for sake of example and simplicity, that you have an authoritative game server that sends state to its clients every 45ms. The clients are interpolating state with an interpolation delay of 100 ms. Finally, the clients are rendering a new frame every 15ms. When state is updated on the client, the client time is set from the incoming state update. Each time a frame renders, we take the render time (client time - interpolation delay) and identify a previous and target state to interpolate from. To calculate the interpolation amount/factor, we take the difference of the render time and previous state time and divide by the difference of the target state and previous state times: var factor = ((renderTime - previousStateTime) / (targetStateTime - previousStateTime)) Problem: In the example above, we are effectively displaying the same interpolated state for 3 frames before we collected the next server update and a new client (render) time is set. The rendering is mostly smooth, but there is a dash of jaggedness to it. Question: Given the example above, I'd like to think that the interpolation amount/factor should increase with each frame render to smooth out the movement. Should this be considered and, if so, what is the best way to achieve this given the information from above?

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• EPM 11.1.2 - Receive Anonymous Level Security token message in IE8 when trying to access Shared Services or Workspace URL

  - by Ahmed A

  If you get "Receive Anonymous Level Security token" message in IE8 when trying to access Shared Services or Workspace URL.Workaround:a. Go to Start > Run and enter dcomcnfgb. Expand Component Services, Expand Computers and right click on My Computer and select Propertiesc. Click on the Default Properties tab.  Change the Default Authentication Level to Connect.  Click apply and then OK.d. Launch the IE browser again and you will be able to access the URL.

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• How to access shared folders in Ubuntu VM(Oracle Virtualbox) and link them to the home folder(Answered)

  - by Njihia

  I have configured a shared folder between the Windows host and Ubuntu guest. The folder mounts at start up but its empty(It also has a padlock sign.). I have to run the command below to access its content(the padlock sign disappears). sudo mount.vboxsf media ~/media How can i configure it to be run automatically at start up. I've tried adding to the start up programs but nothing happens. Am new to Linux so try to put your answer in a layman's language. Thanks.

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• design an extendible and pluggable business logic flow handler in php

  - by Broncha

  I am working on a project where I need to allow a pluggable way to inject business processes in the normal data flow. eg There is an ordering system. The standard flow of the application is A consumer orders an item. Pays for it and card is authorized. Admin captures the payment. Order is marked as complete and item is shipped. But this process may vary (extra steps in between) for different clients. Say a client would need to validate the location of the consumer before he is presented with a credit card form, OR his policies might require some other processes in between. I am thinking of using State Pattern for processing orders, saving the current state of the order in database, and initializing the state of order from the saved state. I would also need some mechanism, where a small plugin would be able to inject business specific states in the state machine. Am I thinking the right way? Are there already implemented patterns for this kind of situation? I am working with Codeigniter and basically this would mean for me, to redirect to proper controller according to the current state of the order. Like, if the state of the order is unconfirmed then redirect the user to details page and then change the state to pending. If some client would need to do some validation, then register an intermediate state between unconfirmed and pending Please suggest.

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• Hosting rails sites; vps or shared, and how much ram? [closed]

  - by raphael_turtle

  Possible Duplicate: How to find web hosting that meets my requirements? I have 3 rails sites to launch, all of which are fairly small and consisting of a custom cms, one with an online store, and 2 sinatra sites which are mainly static, portfolio sites. What would be the best way to host these sites (I've deployed on dreamhost shared before and some vps's) Is it best to manage them together under one vps? e.g linode $20/m (for the cheapest option, 512mb and would that even be enough ram?) or keep each rails site separate and host each one on a small vps? e.g $4/m (there's often lots of deals like this on webhostingtalk) I'm currently hosting the sinatra sites for free on heroku but finding it a bit slow sometimes.

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• Excellence of Shared Service (ESS)?????? ~After J-SOX????

  - by ???02

  ?? ?1?:After J-SOX?????????????????? ?????????????????????????????????????????????????????1?????J-SOX?????????????????1??????????????????????????????????????????????? ????? ?2?:????????????????????????? ????????????????????????????????????????????????????????????????????????????????????????????? ????? ?3?:SSC??????????????????????? ?????????????????????????????????????????Excellence of Shared Service(ESS)??????????????????????????????????????????????ESS???????????? ?????   ?? ?? ????????????????????&????????? ?????? ????IT??????????????????????????????????????????????????????????????????????????????????????????2005?4??????????????????????????IT???????????????????????????????????????????????????????????????????????????????????????????????????????(???? ?????) ????????????????

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• Service Discovery in WCF 4.0 &ndash; Part 1

  - by Shaun

  When designing a service oriented architecture (SOA) system, there will be a lot of services with many service contracts, endpoints and behaviors. Besides the client calling the service, in a large distributed system a service may invoke other services. In this case, one service might need to know the endpoints it invokes. This might not be a problem in a small system. But when you have more than 10 services this might be a problem. For example in my current product, there are around 10 services, such as the user authentication service, UI integration service, location service, license service, device monitor service, event monitor service, schedule job service, accounting service, player management service, etc..   Benefit of Discovery Service Since almost all my services need to invoke at least one other service. This would be a difficult task to make sure all services endpoints are configured correctly in every service. And furthermore, it would be a nightmare when a service changed its endpoint at runtime. Hence, we need a discovery service to remove the dependency (configuration dependency). A discovery service plays as a service dictionary which stores the relationship between the contracts and the endpoints for every service. By using the discovery service, when service X wants to invoke service Y, it just need to ask the discovery service where is service Y, then the discovery service will return all proper endpoints of service Y, then service X can use the endpoint to send the request to service Y. And when some services changed their endpoint address, all need to do is to update its records in the discovery service then all others will know its new endpoint. In WCF 4.0 Discovery it supports both managed proxy discovery mode and ad-hoc discovery mode. In ad-hoc mode there is no standalone discovery service. When a client wanted to invoke a service, it will broadcast an message (normally in UDP protocol) to the entire network with the service match criteria. All services which enabled the discovery behavior will receive this message and only those matched services will send their endpoint back to the client. The managed proxy discovery service works as I described above. In this post I will only cover the managed proxy mode, where there’s a discovery service. For more information about the ad-hoc mode please refer to the MSDN.   Service Announcement and Probe The main functionality of discovery service should be return the proper endpoint addresses back to the service who is looking for. In most cases the consume service (as a client) will send the contract which it wanted to request to the discovery service. And then the discovery service will find the endpoint and respond. Sometimes the contract and endpoint are not enough. It also contains versioning, extensions attributes. This post I will only cover the case includes contract and endpoint. When a client (or sometimes a service who need to invoke another service) need to connect to a target service, it will firstly request the discovery service through the “Probe” method with the criteria. Basically the criteria contains the contract type name of the target service. Then the discovery service will search its endpoint repository by the criteria. The repository might be a database, a distributed cache or a flat XML file. If it matches, the discovery service will grab the endpoint information (it’s called discovery endpoint metadata in WCF) and send back. And this is called “Probe”. Finally the client received the discovery endpoint metadata and will use the endpoint to connect to the target service. Besides the probe, discovery service should take the responsible to know there is a new service available when it goes online, as well as stopped when it goes offline. This feature is named “Announcement”. When a service started and stopped, it will announce to the discovery service. So the basic functionality of a discovery service should includes: 1, An endpoint which receive the service online message, and add the service endpoint information in the discovery repository. 2, An endpoint which receive the service offline message, and remove the service endpoint information from the discovery repository. 3, An endpoint which receive the client probe message, and return the matches service endpoints, and return the discovery endpoint metadata. WCF 4.0 discovery service just covers all these features in it's infrastructure classes.   Discovery Service in WCF 4.0 WCF 4.0 introduced a new assembly named System.ServiceModel.Discovery which has all necessary classes and interfaces to build a WS-Discovery compliant discovery service. It supports ad-hoc and managed proxy modes. For the case mentioned in this post, what we need to build is a standalone discovery service, which is the managed proxy discovery service mode. To build a managed discovery service in WCF 4.0 just create a new class inherits from the abstract class System.ServiceModel.Discovery.DiscoveryProxy. This class implemented and abstracted the procedures of service announcement and probe. And it exposes 8 abstract methods where we can implement our own endpoint register, unregister and find logic. These 8 methods are asynchronized, which means all invokes to the discovery service are asynchronously, for better service capability and performance. 1, OnBeginOnlineAnnouncement, OnEndOnlineAnnouncement: Invoked when a service sent the online announcement message. We need to add the endpoint information to the repository in this method. 2, OnBeginOfflineAnnouncement, OnEndOfflineAnnouncement: Invoked when a service sent the offline announcement message. We need to remove the endpoint information from the repository in this method. 3, OnBeginFind, OnEndFind: Invoked when a client sent the probe message that want to find the service endpoint information. We need to look for the proper endpoints by matching the client’s criteria through the repository in this method. 4, OnBeginResolve, OnEndResolve: Invoked then a client sent the resolve message. Different from the find method, when using resolve method the discovery service will return the exactly one service endpoint metadata to the client. In our example we will NOT implement this method.   Let’s create our own discovery service, inherit the base System.ServiceModel.Discovery.DiscoveryProxy. We also need to specify the service behavior in this class. Since the build-in discovery service host class only support the singleton mode, we must set its instance context mode to single. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using System.ServiceModel; 7:  8: namespace Phare.Service 9: { 10: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 11: public class ManagedProxyDiscoveryService : DiscoveryProxy 12: { 13: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 14: { 15: throw new NotImplementedException(); 16: } 17:  18: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 19: { 20: throw new NotImplementedException(); 21: } 22:  23: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 24: { 25: throw new NotImplementedException(); 26: } 27:  28: protected override IAsyncResult OnBeginResolve(ResolveCriteria resolveCriteria, AsyncCallback callback, object state) 29: { 30: throw new NotImplementedException(); 31: } 32:  33: protected override void OnEndFind(IAsyncResult result) 34: { 35: throw new NotImplementedException(); 36: } 37:  38: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 39: { 40: throw new NotImplementedException(); 41: } 42:  43: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 44: { 45: throw new NotImplementedException(); 46: } 47:  48: protected override EndpointDiscoveryMetadata OnEndResolve(IAsyncResult result) 49: { 50: throw new NotImplementedException(); 51: } 52: } 53: } Then let’s implement the online, offline and find methods one by one. WCF discovery service gives us full flexibility to implement the endpoint add, remove and find logic. For the demo purpose we will use an internal dictionary to store the services’ endpoint metadata. In the next post we will see how to serialize and store these information in database. Define a concurrent dictionary inside the service class since our it will be used in the multiple threads scenario. 1: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 2: public class ManagedProxyDiscoveryService : DiscoveryProxy 3: { 4: private ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata> _services; 5:  6: public ManagedProxyDiscoveryService() 7: { 8: _services = new ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata>(); 9: } 10: } Then we can simply implement the logic of service online and offline. 1: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 2: { 3: _services.AddOrUpdate(endpointDiscoveryMetadata.Address, endpointDiscoveryMetadata, (key, value) => endpointDiscoveryMetadata); 4: return new OnOnlineAnnouncementAsyncResult(callback, state); 5: } 6:  7: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 8: { 9: OnOnlineAnnouncementAsyncResult.End(result); 10: } 11:  12: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 13: { 14: EndpointDiscoveryMetadata endpoint = null; 15: _services.TryRemove(endpointDiscoveryMetadata.Address, out endpoint); 16: return new OnOfflineAnnouncementAsyncResult(callback, state); 17: } 18:  19: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 20: { 21: OnOfflineAnnouncementAsyncResult.End(result); 22: } Regards the find method, the parameter FindRequestContext.Criteria has a method named IsMatch, which can be use for us to evaluate which service metadata is satisfied with the criteria. So the implementation of find method would be like this. 1: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 2: { 3: _services.Where(s => findRequestContext.Criteria.IsMatch(s.Value)) 4: .Select(s => s.Value) 5: .All(meta => 6: { 7: findRequestContext.AddMatchingEndpoint(meta); 8: return true; 9: }); 10: return new OnFindAsyncResult(callback, state); 11: } 12:  13: protected override void OnEndFind(IAsyncResult result) 14: { 15: OnFindAsyncResult.End(result); 16: } As you can see, we checked all endpoints metadata in repository by invoking the IsMatch method. Then add all proper endpoints metadata into the parameter. Finally since all these methods are asynchronized we need some AsyncResult classes as well. Below are the base class and the inherited classes used in previous methods. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.Threading; 6:  7: namespace Phare.Service 8: { 9: abstract internal class AsyncResult : IAsyncResult 10: { 11: AsyncCallback callback; 12: bool completedSynchronously; 13: bool endCalled; 14: Exception exception; 15: bool isCompleted; 16: ManualResetEvent manualResetEvent; 17: object state; 18: object thisLock; 19:  20: protected AsyncResult(AsyncCallback callback, object state) 21: { 22: this.callback = callback; 23: this.state = state; 24: this.thisLock = new object(); 25: } 26:  27: public object AsyncState 28: { 29: get 30: { 31: return state; 32: } 33: } 34:  35: public WaitHandle AsyncWaitHandle 36: { 37: get 38: { 39: if (manualResetEvent != null) 40: { 41: return manualResetEvent; 42: } 43: lock (ThisLock) 44: { 45: if (manualResetEvent == null) 46: { 47: manualResetEvent = new ManualResetEvent(isCompleted); 48: } 49: } 50: return manualResetEvent; 51: } 52: } 53:  54: public bool CompletedSynchronously 55: { 56: get 57: { 58: return completedSynchronously; 59: } 60: } 61:  62: public bool IsCompleted 63: { 64: get 65: { 66: return isCompleted; 67: } 68: } 69:  70: object ThisLock 71: { 72: get 73: { 74: return this.thisLock; 75: } 76: } 77:  78: protected static TAsyncResult End<TAsyncResult>(IAsyncResult result) 79: where TAsyncResult : AsyncResult 80: { 81: if (result == null) 82: { 83: throw new ArgumentNullException("result"); 84: } 85:  86: TAsyncResult asyncResult = result as TAsyncResult; 87:  88: if (asyncResult == null) 89: { 90: throw new ArgumentException("Invalid async result.", "result"); 91: } 92:  93: if (asyncResult.endCalled) 94: { 95: throw new InvalidOperationException("Async object already ended."); 96: } 97:  98: asyncResult.endCalled = true; 99:  100: if (!asyncResult.isCompleted) 101: { 102: asyncResult.AsyncWaitHandle.WaitOne(); 103: } 104:  105: if (asyncResult.manualResetEvent != null) 106: { 107: asyncResult.manualResetEvent.Close(); 108: } 109:  110: if (asyncResult.exception != null) 111: { 112: throw asyncResult.exception; 113: } 114:  115: return asyncResult; 116: } 117:  118: protected void Complete(bool completedSynchronously) 119: { 120: if (isCompleted) 121: { 122: throw new InvalidOperationException("This async result is already completed."); 123: } 124:  125: this.completedSynchronously = completedSynchronously; 126:  127: if (completedSynchronously) 128: { 129: this.isCompleted = true; 130: } 131: else 132: { 133: lock (ThisLock) 134: { 135: this.isCompleted = true; 136: if (this.manualResetEvent != null) 137: { 138: this.manualResetEvent.Set(); 139: } 140: } 141: } 142:  143: if (callback != null) 144: { 145: callback(this); 146: } 147: } 148:  149: protected void Complete(bool completedSynchronously, Exception exception) 150: { 151: this.exception = exception; 152: Complete(completedSynchronously); 153: } 154: } 155: } 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using Phare.Service; 7:  8: namespace Phare.Service 9: { 10: internal sealed class OnOnlineAnnouncementAsyncResult : AsyncResult 11: { 12: public OnOnlineAnnouncementAsyncResult(AsyncCallback callback, object state) 13: : base(callback, state) 14: { 15: this.Complete(true); 16: } 17:  18: public static void End(IAsyncResult result) 19: { 20: AsyncResult.End<OnOnlineAnnouncementAsyncResult>(result); 21: } 22:  23: } 24:  25: sealed class OnOfflineAnnouncementAsyncResult : AsyncResult 26: { 27: public OnOfflineAnnouncementAsyncResult(AsyncCallback callback, object state) 28: : base(callback, state) 29: { 30: this.Complete(true); 31: } 32:  33: public static void End(IAsyncResult result) 34: { 35: AsyncResult.End<OnOfflineAnnouncementAsyncResult>(result); 36: } 37: } 38:  39: sealed class OnFindAsyncResult : AsyncResult 40: { 41: public OnFindAsyncResult(AsyncCallback callback, object state) 42: : base(callback, state) 43: { 44: this.Complete(true); 45: } 46:  47: public static void End(IAsyncResult result) 48: { 49: AsyncResult.End<OnFindAsyncResult>(result); 50: } 51: } 52:  53: sealed class OnResolveAsyncResult : AsyncResult 54: { 55: EndpointDiscoveryMetadata matchingEndpoint; 56:  57: public OnResolveAsyncResult(EndpointDiscoveryMetadata matchingEndpoint, AsyncCallback callback, object state) 58: : base(callback, state) 59: { 60: this.matchingEndpoint = matchingEndpoint; 61: this.Complete(true); 62: } 63:  64: public static EndpointDiscoveryMetadata End(IAsyncResult result) 65: { 66: OnResolveAsyncResult thisPtr = AsyncResult.End<OnResolveAsyncResult>(result); 67: return thisPtr.matchingEndpoint; 68: } 69: } 70: } Now we have finished the discovery service. The next step is to host it. The discovery service is a standard WCF service. So we can use ServiceHost on a console application, windows service, or in IIS as usual. The following code is how to host the discovery service we had just created in a console application. 1: static void Main(string[] args) 2: { 3: using (var host = new ServiceHost(new ManagedProxyDiscoveryService())) 4: { 5: host.Opened += (sender, e) => 6: { 7: host.Description.Endpoints.All((ep) => 8: { 9: Console.WriteLine(ep.ListenUri); 10: return true; 11: }); 12: }; 13:  14: try 15: { 16: // retrieve the announcement, probe endpoint and binding from configuration 17: var announcementEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 18: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 19: var binding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 20: var announcementEndpoint = new AnnouncementEndpoint(binding, announcementEndpointAddress); 21: var probeEndpoint = new DiscoveryEndpoint(binding, probeEndpointAddress); 22: probeEndpoint.IsSystemEndpoint = false; 23: // append the service endpoint for announcement and probe 24: host.AddServiceEndpoint(announcementEndpoint); 25: host.AddServiceEndpoint(probeEndpoint); 26:  27: host.Open(); 28:  29: Console.WriteLine("Press any key to exit."); 30: Console.ReadKey(); 31: } 32: catch (Exception ex) 33: { 34: Console.WriteLine(ex.ToString()); 35: } 36: } 37:  38: Console.WriteLine("Done."); 39: Console.ReadKey(); 40: } What we need to notice is that, the discovery service needs two endpoints for announcement and probe. In this example I just retrieve them from the configuration file. I also specified the binding of these two endpoints in configuration file as well. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> And this is the console screen when I ran my discovery service. As you can see there are two endpoints listening for announcement message and probe message.   Discoverable Service and Client Next, let’s create a WCF service that is discoverable, which means it can be found by the discovery service. To do so, we need to let the service send the online announcement message to the discovery service, as well as offline message before it shutdown. Just create a simple service which can make the incoming string to upper. The service contract and implementation would be like this. 1: [ServiceContract] 2: public interface IStringService 3: { 4: [OperationContract] 5: string ToUpper(string content); 6: } 1: public class StringService : IStringService 2: { 3: public string ToUpper(string content) 4: { 5: return content.ToUpper(); 6: } 7: } Then host this service in the console application. In order to make the discovery service easy to be tested the service address will be changed each time it’s started. 1: static void Main(string[] args) 2: { 3: var baseAddress = new Uri(string.Format("net.tcp://localhost:11001/stringservice/{0}/", Guid.NewGuid().ToString())); 4:  5: using (var host = new ServiceHost(typeof(StringService), baseAddress)) 6: { 7: host.Opened += (sender, e) => 8: { 9: Console.WriteLine("Service opened at {0}", host.Description.Endpoints.First().ListenUri); 10: }; 11:  12: host.AddServiceEndpoint(typeof(IStringService), new NetTcpBinding(), string.Empty); 13:  14: host.Open(); 15:  16: Console.WriteLine("Press any key to exit."); 17: Console.ReadKey(); 18: } 19: } Currently this service is NOT discoverable. We need to add a special service behavior so that it could send the online and offline message to the discovery service announcement endpoint when the host is opened and closed. WCF 4.0 introduced a service behavior named ServiceDiscoveryBehavior. When we specified the announcement endpoint address and appended it to the service behaviors this service will be discoverable. 1: var announcementAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 2: var announcementBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 3: var announcementEndpoint = new AnnouncementEndpoint(announcementBinding, announcementAddress); 4: var discoveryBehavior = new ServiceDiscoveryBehavior(); 5: discoveryBehavior.AnnouncementEndpoints.Add(announcementEndpoint); 6: host.Description.Behaviors.Add(discoveryBehavior); The ServiceDiscoveryBehavior utilizes the service extension and channel dispatcher to implement the online and offline announcement logic. In short, it injected the channel open and close procedure and send the online and offline message to the announcement endpoint.   On client side, when we have the discovery service, a client can invoke a service without knowing its endpoint. WCF discovery assembly provides a class named DiscoveryClient, which can be used to find the proper service endpoint by passing the criteria. In the code below I initialized the DiscoveryClient, specified the discovery service probe endpoint address. Then I created the find criteria by specifying the service contract I wanted to use and invoke the Find method. This will send the probe message to the discovery service and it will find the endpoints back to me. The discovery service will return all endpoints that matches the find criteria, which means in the result of the find method there might be more than one endpoints. In this example I just returned the first matched one back. In the next post I will show how to extend our discovery service to make it work like a service load balancer. 1: static EndpointAddress FindServiceEndpoint() 2: { 3: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 4: var probeBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 5: var discoveryEndpoint = new DiscoveryEndpoint(probeBinding, probeEndpointAddress); 6:  7: EndpointAddress address = null; 8: FindResponse result = null; 9: using (var discoveryClient = new DiscoveryClient(discoveryEndpoint)) 10: { 11: result = discoveryClient.Find(new FindCriteria(typeof(IStringService))); 12: } 13:  14: if (result != null && result.Endpoints.Any()) 15: { 16: var endpointMetadata = result.Endpoints.First(); 17: address = endpointMetadata.Address; 18: } 19: return address; 20: } Once we probed the discovery service we will receive the endpoint. So in the client code we can created the channel factory from the endpoint and binding, and invoke to the service. When creating the client side channel factory we need to make sure that the client side binding should be the same as the service side. WCF discovery service can be used to find the endpoint for a service contract, but the binding is NOT included. This is because the binding was not in the WS-Discovery specification. In the next post I will demonstrate how to add the binding information into the discovery service. At that moment the client don’t need to create the binding by itself. Instead it will use the binding received from the discovery service. 1: static void Main(string[] args) 2: { 3: Console.WriteLine("Say something..."); 4: var content = Console.ReadLine(); 5: while (!string.IsNullOrWhiteSpace(content)) 6: { 7: Console.WriteLine("Finding the service endpoint..."); 8: var address = FindServiceEndpoint(); 9: if (address == null) 10: { 11: Console.WriteLine("There is no endpoint matches the criteria."); 12: } 13: else 14: { 15: Console.WriteLine("Found the endpoint {0}", address.Uri); 16:  17: var factory = new ChannelFactory<IStringService>(new NetTcpBinding(), address); 18: factory.Opened += (sender, e) => 19: { 20: Console.WriteLine("Connecting to {0}.", factory.Endpoint.ListenUri); 21: }; 22: var proxy = factory.CreateChannel(); 23: using (proxy as IDisposable) 24: { 25: Console.WriteLine("ToUpper: {0} => {1}", content, proxy.ToUpper(content)); 26: } 27: } 28:  29: Console.WriteLine("Say something..."); 30: content = Console.ReadLine(); 31: } 32: } Similarly, the discovery service probe endpoint and binding were defined in the configuration file. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> OK, now let’s have a test. Firstly start the discovery service, and then start our discoverable service. When it started it will announced to the discovery service and registered its endpoint into the repository, which is the local dictionary. And then start the client and type something. As you can see the client asked the discovery service for the endpoint and then establish the connection to the discoverable service. And more interesting, do NOT close the client console but terminate the discoverable service but press the enter key. This will make the service send the offline message to the discovery service. Then start the discoverable service again. Since we made it use a different address each time it started, currently it should be hosted on another address. If we enter something in the client we could see that it asked the discovery service and retrieve the new endpoint, and connect the the service.   Summary In this post I discussed the benefit of using the discovery service and the procedures of service announcement and probe. I also demonstrated how to leverage the WCF Discovery feature in WCF 4.0 to build a simple managed discovery service. For test purpose, in this example I used the in memory dictionary as the discovery endpoint metadata repository. And when finding I also just return the first matched endpoint back. I also hard coded the bindings between the discoverable service and the client. In next post I will show you how to solve the problem mentioned above, as well as some additional feature for production usage. You can download the code here.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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• Cyrus: In practical terms, how do end users administer their shared mailboxes?

  - by Nick

  Let's say we have four customer service reps: Billy, Bob, Joe, and Tom. Tom is the department manager. There's a shared Customer Service mailbox on the Cyrus server that they all have access to. Tom, as the manager also has administrative privileges for the shared mailbox. They decide they want to create sub-folders a certain way, and Tom creates them. They're all running Thunderbird, so Tom right-clicks the main folder and chooses "New Subfolder". Now Tom has the Subfolders he needs and the other sales reps have... nothing! Because Cyrus created the Subfolders giving Tom "Full Access" permissions, and everyone else gets no access. So how does Tom give the other reps in his department access to the new folders? As far as Cyrus is concerned, Tom has permission to grant others access to his new mailboxes- But as far as I can tell, there's no option in Thunderbird for granting mailbox permissions. An IT staff member should not have to receive a support request every time someone wants to add a Subfolder to a shared mailbox. That's why we make certain users into mailbox admins in the first place! But asking (non-technical) users to SSH into an IMAP server to run cyradm seems like a bad idea too. Certainly someone has found a solution for this dilemma. Perhaps a Thunderbird extension for setting Cyrus permissions? Or something like umask that forces subfolders to have identical permissions to their parents on creation? And related, what about Sieve configuration? Is there anyway that can be done from the client machine too? Thanks, Nick

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• Pros and Cons of using ASP.NET Session State Server (instead of InProc)?

  - by jdk

  Before I start using Session State server for the benefit of making session state more robust in may apps compared to InProc state, I'd like to find a list of Pros and Cons for evaluation.

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• Can I find out the number of searches on a given keyword, per state?

  - by Philippe

  I know that Google tells you how many times a certain keyword is used in a search. You can use the Google Keyword Tool for that. This tool also allows you to find out the number of "local" searches: this is the number of times a person from a given country searches for this keyword. My questions: can you also find out how many searches originate from a given American state ? In the Keyword Tool, I can only select countries, not states. Any other systems I can use to determine where people are searching for a given keyword?

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• How to remap Fn key combinations (Lenovo G500)

  - by Anatoli

  I am running Kubuntu 13.10 on a Lenovo G500 laptop. My question is similar to this one: How can I remap my F keys on my HP laptop? That is to say, my F1-F12 keys are mapped to certain special functions, and only holding down the Fn key restores access to the standard F1-F12 keys. How do I remap certain keys? I would like to know if there is a way to remap Fx to Fn+Fx and vice-versa. As per the instructions of #87043 I checked my BIOS and there is no option to switch the Fx/Fn key functionality. Googling through Leonovo's support forums indicates a BIOS update enabling this is in the works, but there's no indication of when it will be complete. Using xev I was able to see what X sees when F1-F12 are pressed. Some send separate keycodes, but some are somehow mapped to key combinations or other unknown things: F1 - XF86AudioMute F2 - XF86AudioVolumeLower F3 - XF86AudioVolumeRaise F4 - Alt_L + F4 F5 - F5 F6 - Disables touchapd, cannot quite understand what xev tells me is happening, reenables if disabled (Kernel log reveals these have well-defined scancodes not assigned to any keycodes) F7 - XF86WLAN F8 - Alt_L + Ctrl_L + Tab F9 - Turns off LCD backlight, xev sees nothing F10 - Super_L + p F11 - XF86MonBrightnessLower F12 - XF86MonBrightnessRaise Following the instrusctions on this page: How do I remap certain keys? I remapped all the keys that have definite keycodes (F1, F2, F3, F5, F7, F11, F12) This still leaves the F4, F6, F8, F9, F10 keys not functioning properly. This is especially frustarting since F4, F6, F9 now kill the current window, the touchpad and screen, respectively. Any help on remapping these keys to their proper functions would be much appreciated! -Anatoli xev output for these 5 keys: F4 KeyPress event, serial 40, synthetic NO, window 0x4800001, root 0x9d, subw 0x0, time 3674037, (228,298), root:(911,321), state 0x0, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False FocusOut event, serial 40, synthetic NO, window 0x4800001, mode NotifyGrab, detail NotifyAncestor FocusIn event, serial 40, synthetic NO, window 0x4800001, mode NotifyUngrab, detail NotifyAncestor KeymapNotify event, serial 40, synthetic NO, window 0x0, keys: 4294967197 0 0 0 0 0 0 0 65 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 KeyRelease event, serial 40, synthetic NO, window 0x4800001, root 0x9d, subw 0x0, time 3674040, (228,298), root:(911,321), state 0x8, keycode 70 (keysym 0xffc1, F4), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False KeyRelease event, serial 40, synthetic NO, window 0x4800001, root 0x9d, subw 0x0, time 3674042, (228,298), root:(911,321), state 0x8, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False ClientMessage event, serial 40, synthetic YES, window 0x4800001, message_type 0x12a (WM_PROTOCOLS), format 32, message 0x12b (WM_DELETE_WINDOW) F6 disabling touchpad MappingNotify event, serial 40, synthetic NO, window 0x0, request MappingKeyboard, first_keycode 8, count 248 FocusOut event, serial 40, synthetic NO, window 0x4600001, mode NotifyGrab, detail NotifyAncestor FocusIn event, serial 40, synthetic NO, window 0x4600001, mode NotifyUngrab, detail NotifyAncestor KeymapNotify event, serial 40, synthetic NO, window 0x0, keys: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 MappingNotify event, serial 41, synthetic NO, window 0x0, request MappingKeyboard, first_keycode 8, count 248 F6 enabling touchpad MappingNotify event, serial 42, synthetic NO, window 0x0, request MappingKeyboard, first_keycode 8, count 248 FocusOut event, serial 42, synthetic NO, window 0x4600001, mode NotifyGrab, detail NotifyAncestor FocusIn event, serial 42, synthetic NO, window 0x4600001, mode NotifyUngrab, detail NotifyAncestor KeymapNotify event, serial 42, synthetic NO, window 0x0, keys: 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 MappingNotify event, serial 43, synthetic NO, window 0x0, request MappingPointer, first_keycode 0, count 0 F8 doing whatever it is F8 does KeyPress event, serial 40, synthetic NO, window 0x4600001, root 0x9d, subw 0x0, time 3508985, (13,-12), root:(696,11), state 0x0, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyPress event, serial 40, synthetic NO, window 0x4600001, root 0x9d, subw 0x0, time 3508986, (13,-12), root:(696,11), state 0x8, keycode 37 (keysym 0xffe3, Control_L), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyPress event, serial 40, synthetic NO, window 0x4600001, root 0x9d, subw 0x0, time 3508988, (13,-12), root:(696,11), state 0xc, keycode 23 (keysym 0xff09, Tab), same_screen YES, XLookupString gives 1 bytes: (09) " " XmbLookupString gives 1 bytes: (09) " " XFilterEvent returns: False KeyRelease event, serial 40, synthetic NO, window 0x4600001, root 0x9d, subw 0x0, time 3508989, (13,-12), root:(696,11), state 0xc, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False KeyRelease event, serial 40, synthetic NO, window 0x4600001, root 0x9d, subw 0x0, time 3508991, (13,-12), root:(696,11), state 0x4, keycode 37 (keysym 0xffe3, Control_L), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False KeyRelease event, serial 40, synthetic NO, window 0x4600001, root 0x9d, subw 0x0, time 3508994, (13,-12), root:(696,11), state 0x0, keycode 23 (keysym 0xff09, Tab), same_screen YES, XLookupString gives 1 bytes: (09) " " XFilterEvent returns: False F9 gives no output to xev F10 doing whatever it is F10 does KeyRelease event, serial 40, synthetic NO, window 0x4600001, root 0x9d, subw 0x0, time 3586076, (9,-14), root:(692,9), state 0x0, keycode 10 (keysym 0x31, 1), same_screen YES, XLookupString gives 1 bytes: (31) "1" XFilterEvent returns: False KeyPress event, serial 40, synthetic NO, window 0x4600001, root 0x9d, subw 0x0, time 3586552, (9,-14), root:(692,9), state 0x0, keycode 133 (keysym 0xffeb, Super_L), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyPress event, serial 40, synthetic NO, window 0x4600001, root 0x9d, subw 0x0, time 3586554, (9,-14), root:(692,9), state 0x40, keycode 33 (keysym 0x70, p), same_screen YES, XLookupString gives 1 bytes: (70) "p" XmbLookupString gives 1 bytes: (70) "p" XFilterEvent returns: False KeyRelease event, serial 40, synthetic NO, window 0x4600001, root 0x9d, subw 0x0, time 3586557, (9,-14), root:(692,9), state 0x40, keycode 33 (keysym 0x70, p), same_screen YES, XLookupString gives 1 bytes: (70) "p" XFilterEvent returns: False KeyRelease event, serial 40, synthetic NO, window 0x4600001, root 0x9d, subw 0x0, time 3586560, (9,-14), root:(692,9), state 0x40, keycode 133 (keysym 0xffeb, Super_L), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False

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• Are there any tools to help the user to design a State Machine to be consumed by my application?

  - by kolrie

  When reading this question I remembered there was something I have been researching for a while now and I though Stackoverflow could be of help. I have created a framework that handles applications as state machines. Currently all the state business logic and transactions are handled via Java code. I was looking for some UI implementation that would allow the user to draw the state machines and transactions and generate a file that can later on be consumed by my framework to "run" the workflow according to one or more defined state machines. Ideally I would like to use an open standard like SCXML. The goal as the UI would be to have something like this plugin IBM have for Rational Software Architect: Do you know any editor, plugin or library that would have something similar or at least serve as a good starting point?

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• Could not connect to wireless unitl reboot (nl80211)

  - by user107410

  I'm using Samsung NP900X3C. I have problem with occasionally connecting to WIFI, with Ubuntu 12.10. Sometimes my computer could not connect to WIFI "blab", neither after reboot computer. Only solution is to restart WIFI hotspot. It's public WIFI, used by many users, that don't have that problem. My /var/log/syslog: Nov 12 10:09:39 k15 wpa_supplicant[1308]: wlan0: SME: Trying to authenticate with 64:70:02:89:7c:d7 (SSID='blab' freq=2427 MHz) Nov 12 10:09:39 k15 kernel: [ 8.908610] wlan0: authenticate with 64:70:02:89:7c:d7 Nov 12 10:09:39 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: scanning -> authenticating Nov 12 10:09:39 k15 kernel: [ 8.915032] wlan0: send auth to 64:70:02:89:7c:d7 (try 1/3) Nov 12 10:09:39 k15 wpa_supplicant[1308]: wlan0: Trying to associate with 64:70:02:89:7c:d7 (SSID='blab' freq=2427 MHz) Nov 12 10:09:39 k15 kernel: [ 8.916753] wlan0: authenticated Nov 12 10:09:39 k15 kernel: [ 8.916839] wlan0: waiting for beacon from 64:70:02:89:7c:d7 Nov 12 10:09:39 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: authenticating -> associating Nov 12 10:09:39 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: associating -> disconnected Nov 12 10:09:39 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: disconnected -> scanning Nov 12 10:09:42 k15 wpa_supplicant[1308]: wlan0: SME: Trying to authenticate with 64:70:02:89:7c:d7 (SSID='blab' freq=2427 MHz) Nov 12 10:09:42 k15 kernel: [ 12.386212] wlan0: authenticate with 64:70:02:89:7c:d7 Nov 12 10:09:42 k15 wpa_supplicant[1308]: wlan0: Trying to associate with 64:70:02:89:7c:d7 (SSID='blab' freq=2427 MHz) Nov 12 10:09:42 k15 kernel: [ 12.389114] wlan0: send auth to 64:70:02:89:7c:d7 (try 1/3) Nov 12 10:09:42 k15 kernel: [ 12.391021] wlan0: authenticated Nov 12 10:09:42 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: scanning -> authenticating Nov 12 10:09:42 k15 kernel: [ 12.391332] wlan0: waiting for beacon from 64:70:02:89:7c:d7 Nov 12 10:09:42 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: authenticating -> associating Nov 12 10:09:43 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: associating -> disconnected Nov 12 10:09:43 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: disconnected -> scanning Nov 12 10:09:46 k15 wpa_supplicant[1308]: wlan0: SME: Trying to authenticate with 64:70:02:89:7c:d7 (SSID='blab' freq=2427 MHz) and after restart WiFi, I could connect: Nov 12 10:11:51 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: inactive -> scanning Nov 12 10:11:55 k15 wpa_supplicant[1308]: wlan0: SME: Trying to authenticate with 64:70:02:89:7c:d7 (SSID='blab' freq=2427 MHz) Nov 12 10:11:55 k15 kernel: [ 144.445154] wlan0: authenticate with 64:70:02:89:7c:d7 Nov 12 10:11:55 k15 kernel: [ 144.453994] wlan0: send auth to 64:70:02:89:7c:d7 (try 1/3) Nov 12 10:11:55 k15 wpa_supplicant[1308]: wlan0: Trying to associate with 64:70:02:89:7c:d7 (SSID='blab' freq=2427 MHz) Nov 12 10:11:55 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: scanning -> authenticating Nov 12 10:11:55 k15 kernel: [ 144.455860] wlan0: authenticated Nov 12 10:11:55 k15 kernel: [ 144.458681] wlan0: associate with 64:70:02:89:7c:d7 (try 1/3) Nov 12 10:11:55 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: authenticating -> associating Nov 12 10:11:55 k15 kernel: [ 144.462799] wlan0: RX AssocResp from 64:70:02:89:7c:d7 (capab=0x431 status=0 aid=9) Nov 12 10:11:55 k15 kernel: [ 144.486368] wlan0: associated Nov 12 10:11:55 k15 wpa_supplicant[1308]: wlan0: Associated with 64:70:02:89:7c:d7 Nov 12 10:11:55 k15 kernel: [ 144.487435] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready Nov 12 10:11:55 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: associating -> associated Nov 12 10:11:55 k15 NetworkManager[1004]: <info> (wlan0): supplicant interface state: associated -> 4-way handshake This problem is appearing regulary. My WiFi device control is nl80211. Nov 12 10:09:32 k15 NetworkManager[1004]: <info> (wlan0): using nl80211 for WiFi device control Nov 12 10:09:32 k15 NetworkManager[1004]: <warn> (wlan0): driver supports Access Point (AP) mode Nov 12 10:09:32 k15 NetworkManager[1004]: <info> (wlan0): new 802.11 WiFi device (driver: 'iwlwifi' ifindex: 3) Nov 12 10:09:32 k15 NetworkManager[1004]: <info> (wlan0): exported as /org/freedesktop/NetworkManager/Devices/0 Nov 12 10:09:32 k15 NetworkManager[1004]: <info> (wlan0): now managed Nov 12 10:09:32 k15 NetworkManager[1004]: <info> (wlan0): device state change: unmanaged -> unavailable (reason 'managed') [10 20 2] Nov 12 10:09:32 k15 NetworkManager[1004]: <info> (wlan0): bringing up device.

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• What is the state of the art in OOP?

  - by Ollie Saunders

  I used to do a lot of object-oriented programming and found myself reading up a lot on how to do it well. When C++ was the dominant OOP language there was a very different set of best practices than have emerged since. Some of the newer ideas I know of are BDD, internal DSLs, and the importing of ideas from functional programming. My question is: is there any consensus on the best way to develop object-oriented software today in the more modern languages such as C#, Ruby, and Python? And what are those practices? For instance, I rather like the idea of stateless objects but how many are actually using that in practice? Or, is the state of the art to deemphasize the importance of OOP? This might be the case for some Python programmers but would be difficult for Rubyists.

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• Tab Sweep - State of Java EE, Dynamic JPA, Java EE performance, Garbage Collection, ...

  - by alexismp

  Recent Tips and News on Java EE 6 & GlassFish: • Java EE: The state of the environment (SDTimes) • Extend your Persistence Unit on the fly (EclipseLink blog) • Glassfish 3.1 - AccessLog Format (Ralph) • Java Enterprise Performance - Unburdended Applications (Lucas) • Java Garbage Collection and Heap Analysis (John) • Qu’attendez-vous de JMS 2.0? (Julien) • Dynamically registering WebFilter with Java EE 6 (Markus)

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• Why 11.10 says plymouth errors and "Checking battery state..."?

  - by Aleksi Kinnunen

  I've just installed new Ubuntu 11.10. The installation was successful. But when I start the Ubuntu, the splash screen does not work, and I get error (always some of these) "mountall: Plymouth command failed", "mountall: Connect to Plymouth was lost" or "Checking battery state..." I'm sorry, if the error messages are incorrect because I translated two first of them from Finnish (my system is in Finnish) to English, so they maybe couldn't be just right. I have already asked from our Finnish community, but they couldn't answer. Could anybody here?

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• What is the state-of-the-art for using Broadcom Crystal hardware?

  - by echo-flow

  I just bought a Dell Mini 1012, which comes with a Broadcom Crystal media accelerator chip. I'd like to know what is the current state-of-the-art with regard to using this hardware on Ubuntu? What I mean by this is, what is the best way to install drivers to make use of this hardware, and what media players currently support it? I've read that XBMC currently does, but what about gstreamer? Ideally, I'd like to find a solution so that I can accelerate Flash videos using the device. It seems like one strategy may be to download Flash videos to the hard drive and play them with an external, Crystal-enabled media player, and so that seems like one option, but I'm wondering if any of the free flash alternatives (Gnash and Lightspark) support hardware acceleration of flash video using the Crystal API? It seems like there is a lot of information about all of this on the web, but it's not consolidated, and seems like a rapidly moving target, so any insight anyone may have into this would be appreciated.

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• Using components in the XNA Game State Management example?

  - by Zolomon

  In the game state management example at the App Hub, they say that if you want to use components in the example you can extend the GameScreen to host other components inside itself. I'm having a very hard time trying to tie this up. I tried extending the GameScreen class by adding a public property of public List<DrawableGameCompnent> components { get; set; } and then add my components to that list when I initialize the current screen as well as looping over the components in the LoadContent, Update and Draw methods. However, this doesn't feel like the correct way to go - mainly because it doesn't work when I get to the implementation of my GameplayScreen. Any thoughts?

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• What approaches are available to revert an IDirect3DDevice9 instance to its default render state?

  - by Rafael Goodman

  Given an instance of IDirect3DDevice9, what approaches are available to put it in its original render state (i.e. the state it was in when the device was initially created)? The cleanest way that I've come across is to create a state block via IDirect3DDevice9::CreateStateBlock just after the device has been created so that it can be applied later. Unfortunately, I'm operating under the constraints of an existing project such that I can't modify the device creation code; by the time my component gets the device, its default state has been modified. As a result, I'm looking for alternative approaches. Thx! ~Raf

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