Allow container mem_limit to be null

[allisaurus]

• Resolves mem_limit not followed #570 , mem_limit defaults to 512MB #606

Previously, if no mem_limit was set on a container, the ecs-cli would default it to 512mb, even if task size memory was set. Additionally, if mem_reservation was set but mem_limit was not, the latter would be set to the same value.

This change leaves mem_limit unset (nil) in both cases.

Test 1: container mem_limit null when task level memory set

docker-compose.yml

version: '2'
services:
  wordpress:
    image: wordpress
    ports:
      - "80:80"

ecs-params.yml

version: 1
task_definition:
  ecs_network_mode: bridge
  task_size:
    cpu_limit: 250
    mem_limit: 1gb

CMD out put

$> ~\ecs-cli.exe compose create
INFO[0000] Using ECS task definition                     TaskDefinition="wordpress-test:6"

resulting task definition

{
  "containerDefinitions": [
    {
      "portMappings": [
        {
          "hostPort": 80,
          "protocol": "tcp",
          "containerPort": 80
        }
      ],
      "cpu": 0,
      "memory": null,
      "memoryReservation": null,
      "volumesFrom": [],
      "image": "wordpress",
      "essential": true,
      "name": "wordpress"
    }
  ],
  "memory": "1024",
  "compatibilities": [
    "EC2"
  ],
  "taskDefinitionArn": "arn:aws:ecs:us-west-2:##########:task-definition/wordpress-test:6",
  "family": "wordpress-test",
  "networkMode": "bridge",
  "cpu": "250",
  "revision": 6,
  "status": "ACTIVE",
}

Test 2: mem_reservation set but mem_limit not set

docker-compose.yml

version: '2'
services:
  wordpress:
    image: wordpress
    ports:
      - "80:80"

ecs-params.yml

version: 1
task_definition:
  ecs_network_mode: bridge
  services:
    wordpress:
      mem_reservation: 1gb

CMD output

$> ~\ecs-cli.exe compose create
INFO[0000] Using ECS task definition                     TaskDefinition="wordpress-test:8"

resulting task def

{
  "containerDefinitions": [
    {
      "portMappings": [
        {
          "hostPort": 80,
          "protocol": "tcp",
          "containerPort": 80
        }
      ],
      "cpu": 0,
      "memory": null,
      "memoryReservation": 1024,
      "image": "wordpress",
      "essential": true,
      "name": "wordpress"
    }
  ],
  "memory": null,
  "compatibilities": [
    "EC2"
  ],
  "taskDefinitionArn": "arn:aws:ecs:us-west-2:##########:task-definition/wordpress-test:8",
  "family": "wordpress-test",
  "networkMode": "bridge",
  "cpu": "250",
  "revision": 8,
  "status": "ACTIVE",
  "volumes": []
}

--
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[SoManyHs]

Code LGTM (modulo typo ;)! However could you update the commit message to include what you have in the PR description here? Also, I would change the commit title to be more explicit about memory limit not being set ("empty" confusing bc in go that means 0 for an int, not null).

E.g.

[Bugfix] Allow container memory limit to be null

Previously, if no mem_limit was set on a container, the ecs-cli would default it to 512mb, even if task size memory was set. Additionally, if mem_reservation was set but mem_limit was not, the latter would be set to the same value.

This change leaves mem_limit unset (nil) in both cases.

Resolves #570, #606

[SoManyHs]

EXPECT'D!

[allisaurus]

D: