briareus/lib/service/actions/scale-down-ecs-service.js

Briareus assists with Feature Branch deploys to ECS

'use strict'

const AWS = require('aws-sdk');
const async = require('async');

let action = module.exports = function (pipeline, payload, cb) {
  const ecs = new AWS.ECS();

  // Return if we have no ECS Service
  if (!payload.assets.ecsService) return cb(null, []);

  const describeParams = {
    services: [payload.name],
    cluster: payload.ecsClusterArn,
  };

  const updateParams = {
    service: payload.name,
    cluster: payload.ecsClusterArn,
    desiredCount: 0
  };

  const waitForParams = {
    services: [payload.name],
    cluster: payload.ecsClusterArn
  };

  async.series([
    (next) => ecs.updateService(updateParams, next),
    (next) => {
      ecs.describeServices(describeParams, (err, data) => {
        if (err) return cb(err);
        // If running count is already 0, don't wait for service to be stable. Because we'll never get that event
        if (data.services[0].runningCount === 0) return cb(null, []);
        next();
      });
    },
    (next) => {
      // wait until service is stable, ie all tasks have stopped
      ecs.waitFor('servicesStable', waitForParams, next);
    }
  ], (err) => {
    cb(null, []);
  })
}

action.waiting = 'Scaling down ECS Service';
action.done = 'ECS Service has no task running';