add shephard to automatically update services

closes #1

ansible/playbooks/stacks.yml

@@ -15,3 +15,4 @@
     - {role: inbucket, tags: inbucket}
     - {role: kms, tags: kms}
     - {role: swarm_dashboard, tags: swarm_dashboard}
+    - {role: shephard, tags: shephard}

ansible/roles/shephard/docker-stack.yml

@@ -0,0 +1,42 @@
+version: "3"
+
+services:
+  app:
+    image: mazzolino/shepherd
+    environment:
+      TZ: 'Europe/Amsterdam'
+      FILTER_SERVICES: ''
+      IGNORELIST_SERVICES: ""
+      RUN_ONCE_AND_EXIT: "true"
+    volumes:
+      - type: bind
+        source: /var/run/docker.sock
+        target: /var/run/docker.sock
+        read_only: true
+    deploy:
+      replicas: 0
+      restart_policy:
+        condition: none
+      labels:
+        - swarm.cronjob.enable=true
+        - "swarm.cronjob.schedule=0 2 * * *"
+        - swarm.cronjob.skip-running=true
+      placement:
+        constraints:
+          - node.role == manager
+
+  scheduler:
+    image: crazymax/swarm-cronjob:latest
+    volumes:
+      - type: bind
+        source: /var/run/docker.sock
+        target: /var/run/docker.sock
+        read_only: true
+    environment:
+      - "TZ=Europe/Amsterdam"
+      - "LOG_LEVEL=info"
+      - "LOG_JSON=false"
+    deploy:
+      placement:
+        constraints:
+          - node.role == manager

ansible/roles/shephard/tasks/main.yml

@@ -0,0 +1,15 @@
+- name: Create working directory
+  file:
+    path: /srv/shephard
+    state: directory
+
+- name: Copy Docker stack file
+  copy:
+    src: "{{ role_path }}/docker-stack.yml"
+    dest: /srv/shephard/docker-stack.yml
+
+- name: Deploy Docker stack
+  docker_stack:
+    name: shephard
+    compose:
+      - /srv/shephard/docker-stack.yml