Refactor application upgrade scripts

[briancaffey]

Both the frontend and backend applications are upgraded via AWS CLI calls.

The frontend application upgrade script looks like this:

Script

TASK_FAMILY=$WORKSPACE-$TASK

  # save the task definition JSON to a variable
  TASK_DESCRIPTION=$(aws ecs describe-task-definition \
    --task-definition $TASK_FAMILY \
  )

echo $TASK_DESCRIPTION | jq -r \
  .taskDefinition.containerDefinitions \
  > /tmp/$TASK_FAMILY.json

# write new container definition JSON with updated image
echo "Writing new $TASK_FAMILY container definitions JSON..."

# replace old image URI with new image URI in a new container definitions JSON
cat /tmp/$TASK_FAMILY.json \
  | jq \
  --arg IMAGE "$NEW_FRONTEND_IMAGE_URI" '.[0].image |= $IMAGE' \
  > /tmp/$TASK_FAMILY-new.json

# Get the existing configuration for the task definition (memory, cpu, etc.)
# from the variable that we saved the task definition JSON to earlier
echo "Getting existing configuration for $TASK_FAMILY..."

MEMORY=$( echo $TASK_DESCRIPTION | jq -r \
  .taskDefinition.memory \
)

CPU=$( echo $TASK_DESCRIPTION | jq -r \
  .taskDefinition.cpu \
)

ECS_EXECUTION_ROLE_ARN=$( echo $TASK_DESCRIPTION | jq -r \
  .taskDefinition.executionRoleArn \
)

ECS_TASK_ROLE_ARN=$( echo $TASK_DESCRIPTION | jq -r \
  .taskDefinition.taskRoleArn \
)

# check the content of the new container definition JSON
cat /tmp/$TASK_FAMILY-new.json

# register new task definition using the new container definitions
# and the values that we read off of the existing task definitions
echo "Registering new $TASK_FAMILY task definition..."

aws ecs register-task-definition \
  --family $TASK_FAMILY \
  --container-definitions file:///tmp/$TASK_FAMILY-new.json \
  --memory $MEMORY \
  --cpu $CPU \
  --network-mode awsvpc \
  --execution-role-arn $ECS_EXECUTION_ROLE_ARN \
  --task-role-arn $ECS_TASK_ROLE_ARN \
  --requires-compatibilities "FARGATE"

While this works, there is an easier way to write this using the --cli-input-json flag from the register-task-definition AWS CLI command.

Both the frontend and backend application update scripts should be re-written to use this argument instead of reading out memory, CPU, execution-role-arn, task-role-arn individually.