Ant-Ivy post-retrieve-trigger - ant

Question

I am trying to tackle some technical debt in our Ant/Ivy system and one of my current tasks is to address some post-retrieve behaviors we currently have. By default, our build system retrieves Ivy dependencies and then extracts compressed artifacts (tar, tar.bz2, gzip, zip only) to a dependency folder, so that our projects have a consistent dependency location:
(project.root)/dependency/.archive <- the compressed dependency location
(project.root)/dependency/extracted-foo` <- the uncompressed dependency
The extraction occurs in a post-retrieve-artifact trigger so that we get the benefit of some of the metadata (paths, names, types, etc., all prefixed with 'dep'.
We currently have one property that can be set to turn off this default behavior for all the dependencies specified in an ivy.xml file. Thus, we are left with an all-or-nothing situation. If we want something in-between, we currently have to use our build.xml file and write some custom code. This is painful because the metadata is not readily available.
I would like to retain the use of the all-or-nothing flag but allow projects to selectively extract items - we have several projects whose build.xml files would be greatly simplified if we could knock the extraction process down to an attribute on the artifact itself.
Thus, my thinking is to use an extra attribute on the artifact tag to "inject" this information and override the ivy.retrieve.pattern to search for this attribute.
Ivy.xml
<ivy-module version="2.0" xmlns:e="http://ant.apache.org/ivy/extra">
<dependencies>
<dependency org="my.org" name="foo" rev="${foo.version}" conf="${conf.archive}->*" transitive="false">
<artifact name="megapin" type="war" e:expand="expand"/>
</dependency>
</dependencies>
</ivy-module>
Build.xml
This is where I think I'm having trouble getting the expand extra attribute to show up.
Question 1: This does add the "extract" attribute to the artifact name at retrieve time. I can use the contains clause to check if that is there in the dep.to Is there a way to retrieve the extra attributes (e.g., ${dep.extra.expand} ?
<property name="ivy.retrieve.pattern" value="${dependency.dir}/[conf]/[artifact]-[rev])(-[expand]).[ext]"/>
</property>
<target name="ivy-post-retrieve-trigger">
<local name="doexpand"/>
<condition property="doexpand">
<contains string="${dep.to}" substring="expand" casesensitive="false"/>
</condition>
<!-- this step works if the flag is set properly, so I'm leaving out these non-relevant steps-->
<...extract if:isset="doexpand"... />
ivysettings.xml
This file basically has the trigger and other resolver settings.
<triggers>
<ant-call target="ivy-post-retrieve-trigger" prefix="dep" event="post-retrieve-artifact"/>
</triggers>
Question 2: Any suggestions on a "noexpand" name? My concern with the <contains> clause is that the "expand" is going to get hit all the time.
I think I am close to getting this working - but the only information I get is: Property "doexpand" has not been set and thus it is skipping the extraction step. Q3 Any tips/advice/examples on how to use the extra attribute on a trigger with Ant/Ivy?

Answer 1

I ended up adding some additional debugging statements to Ivy (as compiled from source). In the ant-ivy/src/java/org/apache/ivy/ant/AntCallTrigger.java I added the following line:
Message.verbose("\tp.name=" + p.getName() + " | p.value=" + p.getValue() );
If I modified my dependency in my Ivy.xml file to be:
<dependency org="my.org" name="foo" rev="${foo.version}" conf="${conf.archive}->*" transitive="false">
<artifact name="megapin" type="war" e:expand="true"/>
</dependency>
This showed
[ivy:retrieve] p.name=dep.expand | p.value=true
At which point I could do something like
<isset property="dep.expand"/>
or
<istrue value=${dep.expand}/>
This answers my Q1. Additionally, I don't need to add this to the Ivy retrieve pattern (thus changing the filename after retrieve), can use a "true" or "false" value as desired (Q2), and this general guidance answers Q3.