Thursday, 21 August 2014

WildFly Command Line Interface - Connection Aliases

A while ago now I added a new feature to the WildFly command line interface to add support for aliases to be defined for connections to servers - I realise however that sometimes when it comes to the CLI capabilities such as this are not as visible until someone actually points out that they exist.

Note: This blog post is written based on WildFly 8.1.0.Final, however this feature was added for WildFly 8.0.0.Final under the following issue WFLY-1850.  This feature is also applicable to later versions of WildFly although most likely using a later version of the schema for configuration.

Configuration File

The first thing that may be new to you is that the command line interface is actually configurable, out of the box we include a base configuration and default settings that are compatible with the application server it is bundled with.

By default the file is called jboss-cli.xml and as of WildFly 8.1.0.Final it is using the following namespace urn:jboss:cli:2.0.

When the CLI starts up a sequence of locations are checked for the location of the configuration file: -

  1. If the system property jboss.cli.config is set it is used as the name of the file, this can either be an absolute path or relative to the CLI's working dir.
  2. The working dir is checked for a file called jboss-cli.xml.
  3. The bin folder of the WildFly installation is checked for a file called jboss-cli.xml.
Failing that a default configuration is assumed not based on any file configuration.

Defining Aliases

The default configuration already contains an example of an alias definition so to define an alias first uncomment this block: -

    <!-- Example controller alias named 'Test'
        <controller name="Test">

For each alias definition four pieces of information can be defined: -

  1. A unique name.
  2. The protocol.
  3. The host name.
  4. The port.

Connecting By Alias

Using an alias is no more complicated than if you were already connecting to servers and specifying a host name.

On starting the CLI you can connect using an alias with a command similar to: -

./ -c --controller=Test

Alternatively start the CLI without any arguments and specify the name of the alias when you call connect e.g.

[disconnected /] connect Test

Why Use Aliases

The next question is why would you want to use aliases.

In the first case if you are administering a number of servers as an example you could have development, staging and production by defining aliases you no longer need to remember the address to use to connect to each of the servers - in addition to that should the address of any of these servers be modified in the future you can update the alias definition and continue to use the command you are used to for connecting to that server.

Secondly and one point I did not mention above, the name of the alias could be an address. So say you have a bunch of scripts that always call connect localhost:9999 - by default the server no longer listens on port 9999, an alias can be used to map this to the correct address.

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