def checkContainerInstanceTaskStatus()

in infra/modules/lambda/ecs-scaledown-lambda/index.py [0:0]
44 lines of code
13 McCabe index (conditional complexity)

def checkContainerInstanceTaskStatus(Ec2InstanceId):
    containerInstanceId = None
    clusterName = None
    tmpMsgAppend = None

    # Describe instance attributes and get the Clustername from userdata section which would have set ECS_CLUSTER name
    ec2Resp = ec2Client.describe_instance_attribute(InstanceId=Ec2InstanceId, Attribute='userData')
    userdataEncoded = ec2Resp['UserData']
    userdataDecoded = base64.b64decode(userdataEncoded['Value'])
    logger.debug("Describe instance attributes response %s", ec2Resp)

    tmpList = userdataDecoded.split()
    for token in tmpList:
        if token.find("ECS_CLUSTER") > -1:
            # Split and get the cluster name
            clusterName = token.split('=')[1]
            logger.info("Cluster name %s",clusterName)

    # Get list of container instance IDs from the clusterName
    clusterListResp = ecsClient.list_container_instances(cluster=clusterName)
    containerDetResp = ecsClient.describe_container_instances(cluster=clusterName, containerInstances=clusterListResp[
        'containerInstanceArns'])
    logger.debug("describe container instances response %s",containerDetResp)

    for containerInstances in containerDetResp['containerInstances']:
        logger.debug("Container Instance ARN: %s and ec2 Instance ID %s",containerInstances['containerInstanceArn'],
                                                                         containerInstances['ec2InstanceId'])
        if containerInstances['ec2InstanceId'] == Ec2InstanceId:
            logger.info("Container instance ID of interest : %s",containerInstances['containerInstanceArn'])
            containerInstanceId = containerInstances['containerInstanceArn']

            # Check if the instance state is set to DRAINING. If not, set it, so the ECS Cluster will handle de-registering instance, draining tasks and draining them
            containerStatus = containerInstances['status']
            if containerStatus == 'DRAINING':
                logger.info("Container ID %s with EC2 instance-id %s is draining tasks",containerInstanceId,
                                                                                         Ec2InstanceId)
                tmpMsgAppend = {"containerInstanceId": containerInstanceId}
            else:
                # Make ECS API call to set the container status to DRAINING
                logger.info("Make ECS API call to set the container status to DRAINING...")
                ecsResponse = ecsClient.update_container_instances_state(cluster=clusterName,containerInstances=[containerInstanceId],status='DRAINING')
                # When you set instance state to draining, append the containerInstanceID to the message as well
                tmpMsgAppend = {"containerInstanceId": containerInstanceId}

    # Using container Instance ID, get the task list, and task running on that instance.
    if containerInstanceId != None:
        # List tasks on the container instance ID, to get task Arns
        listTaskResp = ecsClient.list_tasks(cluster=clusterName, containerInstance=containerInstanceId)
        logger.debug("Container instance task list %s",listTaskResp['taskArns'])

        # If the chosen instance has tasks
        if len(listTaskResp['taskArns']) > 0:
            logger.info("Tasks are on this instance...%s",Ec2InstanceId)
            return 1, tmpMsgAppend
        else:
            logger.info("NO tasks are on this instance...%s",Ec2InstanceId)
            return 0, tmpMsgAppend
    else:
        logger.info("NO tasks are on this instance....%s",Ec2InstanceId)
        return 0, tmpMsgAppend