FEAT: Add Deploying ECS Event Action

The new action creates an updated ECS Task definition with a new docker
tag and attaches the new task to an event target so it can be run when
the event is triggered.

* create a new directory for the action
* add an action dot yaml file with descriptions, ids, and inputs.
* add a deploy dot sh script that uses the aws cli to create a new task
  definition and put that task as the target for an event.

deploy-scheduled-ecs/action.yaml

@@ -0,0 +1,42 @@
+name: Deploy Scheduled ECS to Environment
+description: Deploy a Docker image (in ECR) to an ECS task
+
+inputs:
+  role-to-assume:
+    description: IAM role
+    required: true
+  aws-region:
+    description: AWS region to use
+    required: true
+    default: us-east-1
+  ecs-cluster:
+    description: ECS Cluster for the service being updated
+    required: true
+  ecs-service:
+    description: ECS Service containing the task being updated
+    required: true
+  ecs-task-definition:
+    description: task definition to update with new revision
+    required: true
+  docker-tag:
+    description: tag for the docker image to use in the new task definition
+    required: true
+
+runs:
+  using: composite
+  steps:
+    - name: Setup AWS Credentials
+      uses: aws-actions/configure-aws-credentials@v1
+      with:
+        role-to-assume: ${{ inputs.role-to-assume }}
+        aws-region: ${{ inputs.aws-region }}
+    - name: Deploy to ECS
+      id: deploy-ecs
+      run: ${{ github.action_path }}/deploy.sh
+      shell: bash
+      env:
+        AWS_REGION: ${{ inputs.aws-region }}
+        ECS_CLUSTER: ${{ inputs.ecs-cluster }}
+        ECS_SERVICE: ${{ inputs.ecs-service }}
+        ECS_TASK_DEF: ${{ inputs.ecs-task-definition }}
+        DOCKER_TAG: ${{ inputs.docker-tag }}

deploy-scheduled-ecs/deploy.sh

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+#!/bin/sh
+set -e -u
+
+# uncomment to debug
+# set -x
+
+# Register a new ECS Task Definition using the new Docker Image
+# Update the ECS Service with this new Task Definition
+#
+# This was based off of the deploy script in the mbta/actions/deploy-ecs
+# action.
+#
+# Required Arguments
+# - AWS_REGION: region this ecs cluster is deployed in
+# - ECS_CLUSTER: ecs cluster for service being updated
+# - ECS_SERVICE: ecs service containing task being updated
+# - ECS_TASK_DEF: task definition to update revision for
+# - DOCKER_TAG: tag for docker image to use in new task definition
+
+# set default region so we don't have to specify --region everywhere
+export AWS_DEFAULT_REGION="${AWS_REGION}"
+
+# get the contents of the template task definition from ECS 
+echo "Retrieving ${ECS_TASK_DEF}-template task definition..."
+taskdefinition="$(aws ecs describe-task-definition --task-definition "${ECS_TASK_DEF}-template")"
+
+# use retrieved task definition as basis for new revision, but replace image
+echo "Updating container image to ${DOCKER_TAG}."
+newcontainers="$(echo "${taskdefinition}" | \
+  jq '.taskDefinition.containerDefinitions' | \
+  jq --arg tag "${DOCKER_TAG}" 'map(.image="\($tag)")')"
+
+# check to make sure the secrets are included in the new container definition
+if (echo "${newcontainers}" | jq '.[0] | .secrets' | grep '^null$'); then
+  echo "Error: The container definition is missing its 'secrets' block. Deploy cannot proceed."
+  exit 1
+fi
+
+# this task uses fargate, so publish the new task definition
+echo "Publishing new Task Definition."
+aws ecs register-task-definition \
+--family "${ECS_TASK_DEF}" \
+--task-role-arn "$(echo "${taskdefinition}" | jq -r '.taskDefinition.taskRoleArn')" \
+--execution-role-arn "$(echo "${taskdefinition}" | jq -r '.taskDefinition.executionRoleArn')" \
+--network-mode "$(echo "${taskdefinition}" | jq -r '.taskDefinition.networkMode')" \
+--container-definitions "${newcontainers}" \
+--volumes "$(echo "${taskdefinition}" | jq '.taskDefinition.volumes')" \
+--placement-constraints "$(echo "${taskdefinition}" | jq '.taskDefinition.placementConstraints')" \
+--requires-compatibilities "$(echo "${taskdefinition}" | jq -r '.taskDefinition.requiresCompatibilities')" \
+--cpu "$(echo "${taskdefinition}" | jq -r '.taskDefinition.cpu')" \
+--memory "$(echo "${taskdefinition}" | jq -r '.taskDefinition.memory')"
+
+# deploy the new task to our scheduled ecs task
+#
+# inspired by https://doylew.medium.com/updating-aws-ecs-task-definition-and-scheduled-tasks-using-aws-cli-commands-through-deployment-jobs-7cef82262236
+
+# get the task definition arn for the new task definition
+newtaskdefarn="$(aws ecs describe-task-definition --task-definition "${ECS_TASK_DEF}" | \
+    jq -r '.taskDefinition.taskDefinitionArn')"
+# get the events rule for triggering the scheduled task
+eventsrule=$(aws events list-targets-by-rule --rule "run-${ECS_TASK_DEF}")
+# update the events rule json with the new task def arn
+echo $eventsrule | \
+    jq '.Targets[0].EcsParameters.TaskDefinitionArn='\"${newtaskdefarn}\" > \
+    tempEvents.json
+# update the event on aws with temp json
+aws events put-targets --rule "run-${ECS_TASK_DEF}" --cli-input-json file://tempEvents.json