ecs-service-config-getter

Pulls configuration files for services running on AWS ECS

How it works

Uses ENV vars to locate a desired config file, pulls the configuration down to a shared mounted volume. The desired service container awaits the completion, then starts up with its required configs read from the same shared volume.

Usage

Requires necessary IAM permissions to pull from configuration file source.

Example terraform service definition:

resource "aws_ecs_task_definition" "service" {
  family                   = "service"
  requires_compatibilities = ["FARGATE"]
  cpu                      = local.service_cpu
  memory                   = local.service_memory
  network_mode             = "awsvpc"
  task_role_arn            = aws_iam_role.service.arn
  execution_role_arn       = aws_iam_role.service.arn

  volume {
    name = "configs"
  }

  container_definitions = <<JSON
[
  {
    "command": [
      "--config.file=/configs/service.yml"
    ],
    "cpu": ${local.service_cpu - 128},
    "dependsOn": [
        {
            "containerName": "ecs-service-config-getter",
            "condition": "SUCCESS"
        }
    ],
    "essential": true,
    "image": "prom/service:${local.service_version}",
    "logConfiguration": {
      "logDriver": "awslogs",
      "secretOptions": null,
      "options": {
        "awslogs-group": "${aws_cloudwatch_log_group.service.name}",
        "awslogs-region": "eu-west-2",
        "awslogs-stream-prefix": "ecs"
      }
    },
    "memory": ${local.service_memory - 128},
    "mountPoints": [
      {
        "sourceVolume": "configs",
        "containerPath": "/configs"
      }
    ],
    "name": "service",
    "portMappings": [
      {
        "hostPort": ${local.service_port},
        "protocol": "tcp",
        "containerPort": ${local.service_port}
      }
    ]
  },
  {
    "cpu": 128,
    "environment": [
      {
        "name": "CONFIG_PS_ALERTMANAGER_YML",
        "value": "/monitoring/${local.name}/service_yml|/configs/service.yml"
      },
      {
        "name": "CONFIG_PS_NOTIFICATIONS_TMPL",
        "value": "/monitoring/${local.name}/notifications_tmpl|/configs/notifications.tmpl"
      }
    ],
    "essential": false,
    "image": "joeds13/ecs-service-config-getter:1.0.0",
    "logConfiguration": {
      "logDriver": "awslogs",
      "secretOptions": null,
      "options": {
        "awslogs-group": "${aws_cloudwatch_log_group.service.name}",
        "awslogs-region": "eu-west-2",
        "awslogs-stream-prefix": "ecs"
      }
    },
    "memory": 128,
    "mountPoints": [
      {
        "sourceVolume": "configs",
        "containerPath": "/configs"
      }
    ],
    "name": "ecs-service-config-getter"
  }
]
JSON

  tags = {
    Name         = "service"
    source       = "terraform"
    environment  = var.environment
  }
}