Run an ECS task and grab its output

run.sh

#!/bin/bash
set -euo pipefail

# some env vars here

STARTED_BY="$(date +"%T") - $USERNAME"

AWS_DEFAULT_REGION="${REGION}"
TASK_ID=""

# '|| echo $overrides' is used to disable exit on error
# read returns a non-zero exit status if it doesn't find a delimiter, which is always the case when the delimiter is an empty string.
# https://unix.stackexchange.com/questions/265149/why-is-set-o-errexit-breaking-this-read-heredoc-expression/265151#265151
# :facepalm:
echo "Setting task overrides"
read -r -d '' OVERRIDES << EOL || echo $OVERRIDES
{
  "containerOverrides": [
    {
      "name": "$TASK_NAME",
      "environment": [
        {
          "name": "PROJECT",
          "value": "$PROJECT"
        }
      ]
    }
  ]
}
EOL

run_ecs_task () {
  echo "Starting $TASK_NAME task"
  TASK_ID=$(aws ecs run-task \
    --cluster $CLUSTER \
    --task-definition $TASK_NAME \
    --overrides "$OVERRIDES" \
    --started-by "$STARTED_BY" \
    --query 'tasks[0].taskArn' --output text |
    cut -d "/" -f2)

  echo "Waiting for task $TASK_ID to complete"
  aws ecs wait tasks-stopped \
    --cluster $CLUSTER \
    --tasks $TASK_ID
  echo "Task completed"
}

get_ecs_logs () {
  TASK_ID=$1
  echo "Getting logs for task $TASK_ID"
  aws logs get-log-events \
    --log-group-name "$LOG_GROUP" \
    --log-stream-name "db/$TASK_NAME/$TASK_ID" \
    --query 'events[*].{message: message}' --output text
}

get_exit_code () {
  TASK_ID=$1
  EXIT_CODE=$(aws ecs describe-tasks \
    --cluster "$CLUSTER" \
    --tasks "$TASK_ID" \
    --query 'tasks[*].containers[0].exitCode' --output text)
  exit $EXIT_CODE
}

run_ecs_task
get_ecs_logs $TASK_ID
get_exit_code $TASK_ID