Added support for ECS Secrets

[PettitWesley]

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

[PettitWesley]

@SoManyHs @allisaurus

Regarding the mock changes, I ran make generate using the latest version of mockgen. When I run make generate multiple times on the code, there is no additional diff, so these changes seems to be stable. I suspect that mockgen has rejiggered how they create mocks a little bit, and that's why there's some extra changes. There's nothing weird with the license or year anymore though.

[PettitWesley]

Testing:

ECS Params file:

version: 1
task_definition:
  task_execution_role: ecsExecutionRole
  services:
    redis:
      secrets:
        - value_from: /mysecrets/dbpassword
          name: DB_PASSWORD
        - value_from: /mysecrets/dbusername
          name: DB_USERNAME

$ ecs-cli compose create
INFO[0000] Using ECS task definition                     TaskDefinition="secrets:1"

Results in this task def (only key fields are shown):

{
  "executionRoleArn": "arn:aws:iam::111111111111:role/ecsExecutionRole",
  "containerDefinitions": [
    {
      "linuxParameters": {
        "capabilities": {
          "add": null,
          "drop": null
        },
      },
      "secrets": [
        {
          "valueFrom": "/mysecrets/dbpassword",
          "name": "DB_PASSWORD"
        },
        {
          "valueFrom": "/mysecrets/dbusername",
          "name": "DB_USERNAME"
        }
      ],
      "image": "redis:latest",
      "essential": true,
      "name": "redis"
    }
  ],
  "taskDefinitionArn": "arn:aws:ecs:us-west-2:144718711470:task-definition/secrets:1",
  "family": "secrets",
  "requiresAttributes": [
    {
      "targetId": null,
      "targetType": null,
      "value": null,
      "name": "com.amazonaws.ecs.capability.docker-remote-api.1.17"
    },
    {
      "targetId": null,
      "targetType": null,
      "value": null,
      "name": "ecs.capability.secrets.ssm.environment-variables"
    }
  ],
  "requiresCompatibilities": [
    "EC2"
  ],
  "revision": 1,
  "status": "ACTIVE",
}

[SoManyHs]

Can you also include updates to the README?

[SoManyHs]

Were you not going to make one of these an ARN just for purposes of documentation through tests?

[PettitWesley]

Oh yeah, will do!

[ryandev421]

This doesn't work on fargate with following error.

The specified platform does not satisfy the task definition’s required capabilities.

[ajchida]

@ryanpark91
"Important
This feature is not yet supported for tasks using the Fargate launch type."

https://docs.aws.amazon.com/AmazonECS/latest/developerguide/specifying-sensitive-data.html

This feature is not supported on fargate (yet)