How can I get ant parallel to not multiplex/interleave my log entries?

Question

When I run or in a tag ant multiplexes the logs mixing the output of each task together. I'd like something more easily read/grokked.

I have tried the following approaches and they are better than nothing, but still not what I'm looking for. The following echos the non-interleaved log output at the end of the log, but it also has the combined and mixed output of the two tasks first.

Is there a way I can tell ant ONLY output to the file in question and don't bubble up the log output to the caller?

<parallel>
  <ant target="task1" output=${log.dir}/task1.log"/>
  <ant target="task2" output=${log.dir}/task2.log"/>
</parallel>
<loadfile property="task1" srcfile="${log.dir}/task1.log"/>
<loadfile property="task2" srcfile="${log.dir}/task2.log"/>
<echo>Results:
Task1: ${task1}
---
Task2: ${task2}
</echo>

Answer 1

I have two possible solutions:

• write my own antcall task that handles logging differently
• forget about the console and use record to control logging to a file

I'm going to go with the second because it is the easiest to implement and because I'm probably moving to gradle later on where I'll solve this a different way (but probably following a similar pattern)

The main ant task will use record to turn on and off logging to a build.log. Prior to parallel it will disable logging, let the sub-ant log to files. After they complete ant will load and echo the output. The console output continues to be blended and the build.log is serialized.

It's a little klunky but not too bad.

<project name="antExperiments" default="para" basedir=".">

    <!-- Logging Control -->
    <property  name="build.log.dir" location="${basedir}/logs"/>


    <!-- - - - - - - - - - - - - - - - - - 
          macro: activate logging (defaults to ${build.log.dir}/build.log)                      
         - - - - - - - - - - - - - - - - - -->
    <macrodef name="start.log">
      <attribute name="name" default="build"/>
      <attribute name="dir" default="${build.log.dir}"/>
      <attribute name="append" default="false"/>
      <sequential>
        <record action="start" append="@{append}" name="@{dir}/@{name}.log"/>
      </sequential>
    </macrodef>

    <!-- - - - - - - - - - - - - - - - - - 
          macro: deactivate logging (defaults to ${build.log.dir}/build.log)                      
         - - - - - - - - - - - - - - - - - -->
    <macrodef name="stop.log">
      <attribute name="name" default="build"/>
      <attribute name="dir" default="${build.log.dir}"/>
      <attribute name="append" default="false"/>
      <sequential>
        <record action="stop" append="@{append}" name="@{dir}/@{name}.log"/>
      </sequential>
    </macrodef>

    <target  name="clean">
        <delete dir="${build.log.dir}"/>
        <mkdir  dir="${build.log.dir}"/>
    </target>

    <!-- - - - - - - - - - - - - - - - - - 
          target: main.init
          Initialization for Top Level build - not used by subants                      
         - - - - - - - - - - - - - - - - - -->
    <target name="main.init">
        <start.log/>
    </target>

    <!-- ================================= 
          target: para
          top level build runs 2 jobs in parallel producing interleaved hard to read
          on to standard output and non interleaved more easily understood logging 
          to build.log
         ================================= -->  
    <target  name="para" depends="main.init,clean">
        <stop.log/> <!-- disable top level logging -->
        <parallel threadcount="4" pollinterval="50">
            <ant output="${build.log.dir}/proc1.log" target="proc1">
                <property name="proc" value="proc1"/>
            </ant>
            <ant output="${build.log.dir}/proc2.log" target="proc2">
                <property name="proc" value="proc2"/>                    
            </ant>
        </parallel>
        <start.log/> <!-- enable top level logging -->

        <!-- Non interleaved output -->
        <loadfile property="p1" srcfile="${build.log.dir}/proc1.log"/>
        <loadfile property="p2" srcfile="${build.log.dir}/proc2.log"/>
        <echo>
--------------------------
BuildJob: proc1         
OUTPUT: ******************
${p1}
**************************
--------------------------
BuildJob: proc2         
OUTPUT: ******************
${p2}
**************************


BUILD LOG: ${build.log.dir}/build.log           
</echo>     
    </target>


    <target name="init">
        <echo>Init called by ${proc}</echo>
    </target>

    <target name="proc1" depends="init">
        <echo>PROC1.......................
        </echo>
        <exec dir="${basedir}" executable="cmd">
            <arg line="/c dir \"/>
        </exec>
    </target>
    <target name="proc2" depends="init">
        <echo>PROC2..........2222222.......
        </echo>
        <exec dir="${basedir}" executable="cmd">
            <arg line="/c dir \sandbox"/>
        </exec>
    </target>
</project>