Counter Campaign

This is a simple campaign that counts from a given value up to 20. It contains a single providers.stage.counter stage, which takes an input value, val, increments it by 1, and passes the updated value through the trigger for the next stage.

A conditional stage selector selects the next stage. If val is less than 20, the selector routes execution back to the same counter stage, creating a loop. Once val reaches 20, the selector chooses an empty stage instead, terminating the campaign.

Part 1: Run through the sample using maestro

NOTE: This sample assumes you’ve already installed and configured maestro.

1. Point maestro to the Symphony installation:

   maestro config use-context <context name>
   

   You can use maestro config get-context to check for available contexts and the current context.

2. Run the counter campaign sample, which is one of the packaged samples:

   maestro samples run counter-campaign
   

   You should see outputs like:

   Creating campaign counter-campaign ... done
   Creating campaignversion counter-campaign-v-version1 ... done
   Creating activation counter-activation ... done
   

3. Check the activation status:

   ./maestro get activation -n counter-activation --json-path @status.stageHistory[0].outputs
   

   You should see the activation status is 200 (OK), and the output val is 20:

   STATUS  VAL
   200     20
   

Part 2: Understand the campaign

1. Open ~/.symphony/campaigns/counter/campaign-version.yaml to examine the campaign definition.
2. The counter stage uses a providers.stage.counter that takes an input val and increment its value by 1. It then writes the value to its output, which is made avaialble to stageSelector:

   counter:
     name: "counter"
     provider: "providers.stage.counter"
     stageSelector: "${{$if($lt($output(counter,val), 20), counter, '')}}"
     inputs:
       val: "${{$trigger(val, 0)}}"
   

3. The stageSelector selects the next stage to be executed. In this case, it uses a if statement in Symphony expression that checks if the stage output val is larger than 20. If so, it selects counter as the next stage. Otherwise, it selects an empty stage, which causes the activation to stop. This means the counter stage will be repeatedly called until val reaches 20.

Part 3. Clean up

1. If you run Symphony as a process, simply shut down the process.

2. If you run Symphony on Kubernetes, delete the Symphony objects:

   kubectl delete activation counter-activation
   kubectl delete campaignversion counter-campaign-v-version1
   kubectl delete campaign counter-campaign