How to run shell script in Ant while doing search and replace? - ant

Question

I am trying to achieve following with Ant.
I have a property file where we have list of tokens and their values.
This file is passed to Ant and it works great and does all the normal string replacement.
<copy todir="${target_direcotry}" overwrite="true">
<fileset dir="config">
<include name="*.change_me"/>
</fileset>
<filterset begintoken="<" endtoken=">">
<filtersfile file="${property_file}"/>
</filterset>
<mapper type="glob" from="*.change_me" to="*"/>
</copy>
Now If i have one of the token-value pair as follows :
TOKEN_VALUE1=`./run_me.ksh` in property file.
Target file test.xml.change_me has content :
You have <TOKEN_VALUE1> entries present !!!
With above code in build.xml and this new token in property file i am getting content of test.xml after running ant is :
You have `./run_me.ksh` entries present !!!
Output of script run_me.ksh will decide the value this token and give me output as follows :
Scenario 1 :
Run_me.ksh output: 10
Required content of file test.xml after execution :
"You have 10 entries present !!!"
Scenario 1 :
Run_me.ksh output: 20
Required content of file test.xml after execution :
"You have 20 entries present !!!"
Can i achieve this with Ant function/commands to run such shell script during replacements and how ?

Answer 1

It is technically possible to achieve this with Ant using FilterChain and FilterReader (specifically this one: ScriptFilter). However this is not so trivial and may have some portability issues. You may consider either writing your own task (or a specific FilterReader), or simply define a target that executes your shell script and store its result in a property and the use that property as value for token replacement.
Hereafter a snippet of how to launch a script in your token replacement task :
<copy todir="${target.dir}" overwrite="true">
<fileset dir="${config.dir}">
<include name="*.change_me" />
</fileset>
<filterchain>
<!-- replace token with value in the property file (i.e. `run_me.sh`) -->
<filterreader classname="org.apache.tools.ant.filters.ReplaceTokens">
<param type="propertiesfile" value="${token.properties}" />
</filterreader>
<tokenfilter>
<!-- split result along a specific pattern ('`' character for instance). -->
<stringtokenizer delims="`" delimsaretokens="false" />
<!-- apply a script filter to execute shell if token is script name -->
<scriptfilter language="javascript">
<![CDATA[
if( self.getToken().indexOf(".sh") != -1 ){
<!-- rely on ant Exec task to run script -->
exectask = project.createTask("exec");
exectask.setExecutable("sh");
exectask.createArg().setValue(self.getToken());
<!-- store output in an ant property : -->
exectask.setOutputproperty("result");
exectask.perform();
<!-- retrieve the ant property and use it to replace current token -->
self.setToken(project.getProperty("result"));
}
]]>
</scriptfilter>
</tokenfilter>
</filterchain>
<mapper type="glob" from="*.change_me" to="*" />
</copy>