Azure Service Fabric - Configure service instance parameters using Powershell

Is it possible to inject parameters at run time into a Guest Executable via the Settings.xml file or another means? I have a GuestExecutable which I need to pass some configuration to it - a URL at service creation time.

I need two instances of the service running with different parameters, the service instance information has to differ in terms of a custom parameter I need to pass through . Is this possible using Powershell or, do I need to version the config and create a new version?

Thanks in advance

Solution

Have you tried the following command: New-ServiceFabricApplication ?

When you create your application manifest file, the parameters will contain replaceable parameters that you set when you register a new application.

An ApplicationManifest.xml example like this:

<?xml version="1.0" encoding="utf-8"?>
<ApplicationManifest ApplicationTypeName="MyAppTypeName" ApplicationTypeVersion="1.0.0" xmlns=...>
  <Parameters>
    <Parameter Name="Web1_InstanceCount" Value="-1" />
    <Parameter Name="ENVIRONMENT_NAME" Value="DEV" />
    <Parameter Name="FEPlacementConstraints" Value="NodeTypeName==FrontEnd" />
  </Parameters>
  <ServiceManifestImport>
    <ServiceManifestRef ServiceManifestName="MyServicePkg" ServiceManifestVersion="1.0.0" />
    <ConfigOverrides />
    <EnvironmentOverrides />
  </ServiceManifestImport>
  <DefaultServices>
    <Service Name="Web1">
      <StatelessService ServiceTypeName="MyServiceType" InstanceCount="[Web1_InstanceCount]">
        <SingletonPartition />
        <PlacementConstraints>[FEPlacementConstraints]</PlacementConstraints>
      </StatelessService>
    </Service>
  </DefaultServices>
</ApplicationManifest>

You would change the settings file using config overrides like this:

<ConfigOverrides>
  <ConfigOverride Name="Config">
    <Settings>
      <Section Name="MyConfigSection">
        <Parameter Name="MySetting" Value="[ENVIRONMENT_NAME]"/>
      </Section>
    </Settings>
  </ConfigOverride>
</ConfigOverrides>

Or you could set environment variables on your service like this:

<EnvironmentOverrides CodePackageRef="Code">
  <EnvironmentVariable Name="ASPNETCORE_ENVIRONMENT" Value="[ENVIRONMENT_NAME]" />
</EnvironmentOverrides>

In my opinion the environment overrides would work better on your case, because most guest executable are not flexible on how you can configure them but generally they accept environment variables.

Then you:

Upload your application with: Copy-ServiceFabricApplicationPackage
Register your application with Register-ServiceFabricApplicationType
And then you register each new app with the settings you need:

New-ServiceFabricApplication -ApplicationName fabric:/myapp/todolist-dev -ApplicationTypeName "MyAppTypeName" -ApplicationTypeVersion "1.0.0" -ApplicationParameter @{Web1_InstanceCount='-1'; ENVIRONMENT_NAME='DEV'}

New-ServiceFabricApplication -ApplicationName fabric:/myapp/todolist-uat -ApplicationTypeName "MyAppTypeName" -ApplicationTypeVersion "1.0.0" -ApplicationParameter @{Web1_InstanceCount='-1'; ENVIRONMENT_NAME='UAT'}

The only down side of this approach is that you would end up with two applications, but don't think would be a problem for you, they will be managed mostly the same way as you would do with a single application.

if you strictly need to run both together on same application, you could do some workarounds:

Using multiple Config packages(don't think would work well with guest executables, but works well with reliable services
Using the startup script, where you would add the logic to pass the parameter to your startup exe, something like the following:

In your ServiceManifest.xml:

  <CodePackage Name="Code" Version="1.0.0">
    <EntryPoint>
      <ExeHost>
        <Program>start.bat</Program>
        <WorkingFolder>CodePackage</WorkingFolder>
      </ExeHost>
    </EntryPoint>
  </CodePackage>

On the same folder (code) of your .exe, you create the start.bat file with following contents:

myApp.exe %EnvironmentVariableNameSetBySF%