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ufo tasks build

Usage

ufo tasks build

Description

Build task definitions.

Summarized Example

ufo tasks build

Builds all the task defintiions. Note all the existing ufo/output generated task defintions are wiped out.

Explanation

The command ufo tasks build generates the task definitions locally and writes them to the output/ folder. There are 2 files that it uses in order to produce the raw AWS task definitions files.

  1. ufo/templates/main.json.erb
  2. ufo/task_definitions.rb

Here’s an example of each of them:

main.json.erb:

{
    "family": "<%= @family %>",
    "containerDefinitions": [
        {
            "name": "<%= @name %>",
            "image": "<%= @image %>",
            "cpu": <%= @cpu %>,
            <% if @memory %>
            "memory": <%= @memory %>,
            <% end %>
            <% if @memory_reservation %>
            "memoryReservation": <%= @memory_reservation %>,
            <% end %>
            <% if @container_port %>
            "portMappings": [
                {
                    "containerPort": "<%= @container_port %>",
                    "protocol": "tcp"
                }
            ],
            <% end %>
            "command": <%= @command.to_json %>,
            <% if @environment %>
            "environment": <%= @environment.to_json %>,
            <% end %>
            <% if @awslogs_group %>
            "logConfiguration": {
                "logDriver": "awslogs",
                "options": {
                    "awslogs-group": "<%= @awslogs_group %>",
                    "awslogs-region": "<%= @awslogs_region || 'us-east-1' %>",
                    "awslogs-stream-prefix": "<%= @awslogs_stream_prefix %>"
                }
            },
            <% end %>
            "essential": true
        }
    ]
}

task_definitions.rb:

task_definition "demo-web" do
    source "main" # will use ufo/templates/main.json.erb
    variables(
    family: task_definition_name,
    name: "web",
    container_port: helper.dockerfile_port,
    command: ["bin/web"]
  )
end

task_definition "demo-worker" do
    source "main" # will use ufo/templates/main.json.erb
    variables(
    family: task_definition_name,
    name: "worker",
    command: ["bin/worker"]
  )
end

task_definition "demo-clock" do
    source "main" # will use ufo/templates/main.json.erb
    variables(
    family: task_definition_name,
    name: "clock",
    command: ["bin/clock"]
  )
end

The shared variables are set in the variables folder:

ufo/variables/base.rb:

@image = helper.full_image_name # includes the git sha tongueroo/demo-ufo:ufo-[sha].
@cpu = 128
@memory_reservation = 256
@environment = helper.env_file(".env")

ufo/variables/production.rb:

@environment = helper.env_vars(%Q{
    RAILS_ENV=production
    SECRET_KEY_BASE=secret
})

Ufo combines the main.json.erb template, task_definitions.rb definitions, and variables in the .ufo/variables folder. It then generates the raw AWS formatted task definition in the output folder.

To build the task definitions:

ufo tasks build

You should see output similar to below:

$ ufo tasks build
Building Task Definitions...
Generating Task Definitions:
  ufo/output/demo-web.json
  ufo/output/demo-worker.json
  ufo/output/demo-clock.json
Task Definitions built in ufo/output.
$

Let’s take a look at one of the generated files: .ufo/output/demo-web.json.

{
  "family": "demo-web",
  "containerDefinitions": [
    {
      "name": "web",
      "image": "tongueroo/demo-ufo:ufo-2017-06-11T22-22-32-a18aa30",
      "cpu": 128,
      "memoryReservation": 256,
      "portMappings": [
        {
          "containerPort": "3000",
          "protocol": "tcp"
        }
      ],
      "command": [
        "bin/web"
      ],
      "environment": [
        {
          "name": "RAILS_ENV",
          "value": "staging"
        }
      ],
      "essential": true
    }
  ]
}

If you need to modify the task definition template to suite your own needs it is super simple, just edit main.json.erb. No need to dive deep into internal code that builds up the task definition with some internal structure. It is all there for you to fully control.

Options

[--image-override=IMAGE_OVERRIDE]  # Override image in task definition for quick testing

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