Write containerOverwrites from Lambda to Container

Question

Hello All

I have a step function that is calling a lambda, which does some processing, and gets the id of the job that needs to be processed by the ecs runtask.

What I am trying to do is to pass the job Id as containerOverride so that each run a different Id can be passed to the ecs Run task.

Here is the dummy lambda Output:

```
Test Event Name
dummyTest

Response
{
  "containerOverrides": " [ { \"name\": \"getFileTask\", \"environment\": [ { \"name\": \"name1\", \"value\": \"123\" }, { \"name\": \"DATE\", \"value\": \"1234-12-12\" }, { \"name\": \"SCRIPT\", \"value\": \"123456\" } ] } ] "
}

```

Dummy Lambda Code:

```
def lambda_handler(event, context):
    # TODO implement
    print("Success")
    
    overridden_Text = ' [ { "name": "getFileTask", "environment": [ { "name": "name1", "value": "123" }, { "name": "DATE", "value": "1234-12-12" }, { "name": "SCRIPT", "value": "123456" } ] } ] '
    
    return{
        'containerOverrides': overridden_Text

}

```

Here is the record when the ECS run task is triggered(TaskStateEntered) from the step function:

```
{
  "name": "ECS RunTask",
  "input": {
    "containerOverrides": " [ { \"name\": \"getFileTask\", \"environment\": [ { \"name\": \"name1\", \"value\": \"123\" }, { \"name\": \"DATE\", \"value\": \"1234-12-12\" }, { \"name\": \"SCRIPT\", \"value\": \"123456\" } ] } ] "
  },
  "inputDetails": {
    "truncated": false
  }
}

```

The issue is that when the run task enters the TaskSubmitted stage:

```

"LastStatus": "PROVISIONING",
        "LaunchType": "FARGATE",
        "Memory": "4096",
        "Overrides": {
          "ContainerOverrides": [
            {
              "Command": [],
              "Environment": [],
              "EnvironmentFiles": [],
              "Name": "getFileTask",
              "ResourceRequirements": []
            }
          ],
          "InferenceAcceleratorOverrides": []
        },
        "PlatformFamily": "Linux",
        "PlatformVersion": "1.4.0",
        "StartedBy": "AWS Step Functions",
```

For what ever reasons the Environment variable is not being pushed from lambda output to the Container as launch override. 
Is there something that I am doing incorrectly ?

Thanks

Answer

Container overrides need to go into the `Parameters` attributes of your Action in your state machine. Here is an example that will retrieve the `"foo"` attribute from the input and set it as an environment variable:

```
{  
   "States":{  
      ...,
      "Manage ECS task":{  
         "Type":"Task",
         "Resource":"arn:aws:states:::ecs:runTask.waitForTaskToken",
         "Parameters":{  
            "LaunchType":"FARGATE",
            "Cluster":"cluster-arn",
            "TaskDefinition":"job-id",
            "Overrides":{  
               "ContainerOverrides":[  
                  {  
                     "Name":"container-name",
                     "Environment":[  
                        {  
                           "Name":"FOO_FROM_INPUT",
                           "Value.$":"$.foo"
                        }
                     ]
                  }
               ]
            }
         }
      }
   }
}
```

If your input supplies the *entire value* of the `"ContainerOverrides"` configuration, then you can do something like this:

```
{  
   "States":{  
      ...,
      "Manage ECS task":{  
         "Type":"Task",
         "Resource":"arn:aws:states:::ecs:runTask.waitForTaskToken",
         "Parameters":{  
            "LaunchType":"FARGATE",
            "Cluster":"cluster-arn",
            "TaskDefinition":"job-id",
            "Overrides":{  
               "ContainerOverrides.$": "$.containerOverrides"
            }
         }
      }
   }
}
```

See also [Pass State Input as Parameters Using Paths](https://docs.aws.amazon.com/step-functions/latest/dg/connect-parameters.html#connect-parameters-path) in the Step Functions documentation.

Write containerOverwrites from Lambda to Container

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