ecsrun

ecsrun

A simple, but powerful, program that can run docker images inside an ECS cluster, stream output, and clean up after itself.

How to install

go get github.com/cep21/ecsrun

What it does

This program follows these general steps:

1. Generate a task definition from .task.json
2. Store the generated task definition into ECS
3. Generate a run task definition from .run.json
4. Execute the task defined inside the generated template
5. Insect all task containers for any awslogs loggers and stream those loggers to stdout.
6. Wait for the task to end or SIGINT (ctrl+C).
7. Signal the running task to stop.
8. Delete the task definition created in step 2.

How to use

Create two files, a .run.json and .task.json. The file .task.json should look like a task definition. The file .run.json should look like an ECS run task definition.

There is an example of both inside example.run.json and example.task.json.

Each are processed as golang text templates. The task generator has access to the environment (see the example for how calling into environment variables work). The run template has access to both the environment and the generated task definition. For example, when defining the run template there is the code "TaskDefinition": "{{ .Task.TaskDefinitionArn }}", which is how we substitute the generated task definition into the run template.

Example output

Running the example (which runs ubuntu date command). Note: You can turn off verbose logging with -verbosity 0

< SUBNET=subnet-XYZ CLUSTER=cluster-XYZ LOGGROUP=loggroup-XYZ EXECUTION_ROLE=arn:aws:iam::555555555:role/task-exec-role AWS_REGION=us-west-2 ecsrun -prefix example
2018/10/11 11:07:38 Registering task definition with ECS (family=ubuntu-testing-image)
2018/10/11 11:07:38 Running task inside ECS
2018/10/11 11:07:39 Waiting for task to leave pending state
2018/10/11 11:08:10 Now streaming task output
2018/10/11 11:08:10 Streaming from us-west-2 - loggroup-XYZ - ubuntu-image/ubuntu-image/170ac788-181d-4ac5-bc97-d10054ef03f7
2018/10/11 11:08:11 Task no longer in running state
Thu Oct 11 18:08:09 UTC 2018
2018/10/11 11:08:11 waiting for task to finish and return an exit code
2018/10/11 11:08:12 Removing this task definition from ECS ubuntu-testing-image:23