APropOS

Configure Ant to use Apropos

Since Ant can load properties form any URL and Apropos can export properties in a standard format, the integration of both is quite simple. All you need to do is to note the export URL of your package and tell Ant's to get properties from there.

The basics

Find correct export URL

The export URL is the one that appears in your browser's location after you click on "Export" button. It is of the following form :

 http://HOST:PORT/PATH/get?name=PACKAGE_NAME&type=properties

So, assuming your server runs on localhost (port 8080) and you haven't changed the application name, the export URL of "alice@team1 build" package from the example page will look like this:

 http://localhost:8080/apropos/get?name=alice@team1%20build&type=properties

Update build.xml

Knowing the correct export URL, configuring Ant comes down to adding the following line to build.xml

 <property url="http://localhost:8080/apropos/get?name=alice@team1%20build&amp;type=properties"/>

Optimizations and hints

Auto download properties

There is really no need to call Apropos on every build. First of all, properties do not change that often and second, but more important, you would probably want to be able to build your project even when Apropos is not available (network problems, server restarts, etc). Ant can download and store files so this comes in handy:

<get 
        src="http://localhost:8080/apropos/get?name=alice@team1%20build&amp;type=properties"
        dest="alice_team1_build.properties"
        ignoreerrors="true"
        usetimestamp="true"
        />
<property file="alice_team1_build.properties"/>

Using environment properties to determine what to download

There is a one quite big issue with the above example. The build now contains settings specific for Alice which means build.xml can not be shared among all developers. To work around this an environment properties can be used:

<exec 
        executable="hostname" 
        osfamily="unix" 
        failifexecutionfails="false" 
        outputproperty="env.COMPUTERNAME"
        />
        
<property name="env.HOSTNAME" value="${env.COMPUTERNAME}"/>
<property environment="env"/>

<get 
        src="http://localhost:8080/apropos/get?name=${env.USER}@${env.HOSTNAME}%20build&amp;type=properties"
        dest="${env.USER}_${env.HOSTNAME}_build.properties"
        ignoreerrors="true"
        usetimestamp="true"
        />

<property file="${env.USER}_${env.HOSTNAME}_build.properties"/>

Providing an alternative properties

The above example will work for Alice but it will fail for any user who wishes to use team's default properties and doesn't have own package in Apropos. For such users and alternative should be provided. Since Ant does not overwrite property values all we need to do is to specify few files in order from most specific one to most general one:

<exec 
        executable="hostname" 
        osfamily="unix" 
        failifexecutionfails="false" 
        outputproperty="env.COMPUTERNAME"
        />
        
<property name="env.HOSTNAME" value="${env.COMPUTERNAME}"/>
<property environment="env"/>

<get 
        src="http://localhost:8080/apropos/get?name=${env.USER}@${env.HOSTNAME}%20build&amp;type=properties"
        dest="${env.USER}_${env.HOSTNAME}_build.properties"
        ignoreerrors="true"
        usetimestamp="true"
        />
<get 
        src="http://localhost:8080/apropos/get?name=${env.HOSTNAME}%20build&amp;type=properties"
        dest="${env.HOSTNAME}_build.properties"
        ignoreerrors="true"
        usetimestamp="true"
        />
<get 
        src="http://localhost:8080/apropos/get?name=build&amp;type=properties"
        dest="build.properties"
        ignoreerrors="true"
        usetimestamp="true"
        />

<property file="${env.USER}_${env.HOSTNAME}_build.properties"/> 
<property file="${env.HOSTNAME}_build.properties"/> 
<property file="build.properties"/>

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