It is supposed to be a simple task. I need the image uri that was pushed by ECRPushImage task in Azure DevOps on the next task. ECRPushImage task has outputVariable variable, so let say I set that to ImageUri on my azure-pipelines.yml

- task: ECRPushImage@1
  inputs:
    ...
    outputVariable: 'ImageUri'

According to this article https://learn.microsoft.com/en-us/azure/devops/pipelines/process/variables?view=azure-devops&tabs=yaml%2Cbatch#use-output-variables-from-tasks, I also need to set name on the task:

- task: ECRPushImage@1
  name: ECR
  inputs:
    ...
    outputVariable: 'ImageUri'

So, I can use the variable like following:

- script: echo $(ECR.ImageUri) 

But it doesn't work, the variable was not replaced. I also tried other runtime syntax in https://learn.microsoft.com/en-us/azure/devops/pipelines/process/variables?view=azure-devops&tabs=yaml%2Cbatch#understand-variable-syntax.

So, I went to the GitHub https://github.com/aws/aws-toolkit-azure-devops/blob/master/src/tasks/ECRPushImage/TaskOperations.ts#L81 and it does a simple task.setVariable().

According to the setVariable documentation https://learn.microsoft.com/en-us/azure/devops/pipelines/process/set-variables-scripts?view=azure-devops&tabs=bash#about-tasksetvariable, we can access the variable without the name, so it becomes:

- task: ECRPushImage@1
  inputs:
    ...
    outputVariable: 'ImageUri'
- script: echo $(ImageUri)

And it works! That's after 10 iterations of trials and errors.