Passing values within a TeamCity metarunner - powershell

Question

I have a TeamCity metarunner that consolidates two runners. The first runner does a bunch of Powershell stuff to get the right Octopus release to deploy, and it works fine. The second runner tries to deploy that.
<build-runners>
<runner name="Get project release for current branch" type="jetbrains_powershell">
<parameters>
<param name="jetbrains_powershell_bitness" value="x86" />
<param name="jetbrains_powershell_execution" value="PS1" />
<param name="jetbrains_powershell_minVersion" value="4.0" />
<param name="jetbrains_powershell_script_code"><![CDATA[
#Do some powershell stuff here to get the right release
$ProjectRelease="1.2.3.45"
Write-Output "##teamcity[setParameter name='ProjectRelease' value='$ProjectRelease']"
Start-Sleep -s 10
]]></param>
<param name="jetbrains_powershell_script_mode" value="CODE" />
<param name="teamcity.step.mode" value="default" />
</parameters>
</runner>
<runner name="Deploy Project" type="octopus.deploy.release">
<parameters>
<param name="octopus_additionalcommandlinearguments" value="--specificmachines=%AgentList%" />
<param name="octopus_deployto" value="%Octopus.EnvironmentName%" />
<param name="octopus_host" value="%system.Octopus-prod_ServerUrl%" />
<param name="octopus_project_name" value="%ProjectName%" />
<param name="octopus_releasenumber" value="%ProjectRelease%" />
<param name="octopus_version" value="3.0+" />
<param name="octopus_waitfordeployments" value="true" />
<param name="secure:octopus_apikey" value="zxx318ab49dce685b0ae65d94a963ff326672f51fb87c685575c3b6ed4f6eb8a569" />
<param name="teamcity.step.mode" value="default" />
</parameters>
</runner>
</build-runners>
So you can see %ProjectRelease% gets set to 1.2.3.45, and this value can then be used in subsequent build steps - all good there. However for the second runner, on the line:
<param name="octopus_releasenumber" value="%ProjectRelease%" />
%ProjectRelease% is still equal to the default value ("To be populated" and not "1.2.3.45"). How can I pass this value to the Deploy Project runner?

Answer 1

OK, so I found a solution to this, but it is kind of hacky.
By naming ProjectRelease to env.ProjectRelease (and don't forget to add it as a parameter) it becomes an environment parameter which is updated in real time, and thus will work.
Apparently the line:
Write-Output "##teamcity[setParameter name='ProjectRelease' value='$ProjectRelease']"
...doesn't set the parameter until after the whole script has finished. Please let me know if there is a more elegant solution than this!

Answer 2

You should be able to set parameters for the whole metarunner farther up in the xml.
For example:
<?xml version="1.0" encoding="UTF-8"?>
<meta-runner name="YourMetaRunnerName">
<description>YourMetaRunner Description </description>
<settings>
<parameters>
<!-- meta-runner parameters accessible in all build runners
below -->
<param name="ProjectRelease"value="Release.1.2.3.45"/>
You will then be able to use these parameters in subsequent build runners within the MetaRunner. This should be a more contained solution.