feat: support optional container removal before start in upstart/systemd

Author: solarchad

docker/files/service_file.jinja

@@ -8,6 +8,7 @@
 {%- set stopoptions = stopoptions|join(' ') %}
 {%- set args = args|join(' ') %}
 
+{%- set docker_prestart_remove_command = "rm -f %s"|format(name) %}
 {%- set docker_start_command = "run %s --name=%s %s %s %s"|format(runoptions, name, container.image, cmd, args)  %}
 {%- set docker_stop_command = "stop %s %s"|format(stopoptions, name) %}
 {%- set docker_poststop_command = "rm -f %s"|format(name) %}
@@ -16,4 +17,4 @@
 {%- include 'docker/files/systemd.conf' %}
 {%- elif grains['init'] == 'upstart' %}
 {%- include 'docker/files/upstart.conf' %}
-{%- endif %}
+{%- endif %}

docker/files/systemd.conf

@@ -5,13 +5,17 @@ After=docker.service
 
 {%- set remove_on_stop = container.get("remove_on_stop", False) %}
 {%- set pull_before_start = container.get("pull_before_start") or False %}
+{%- set remove_before_start = container.get("remove_before_start") or False %}
 
 [Service]
 Restart=always
 {%- if pull_before_start %}
 ExecStartPre=/usr/bin/docker pull {{ container.image }}
 {%- endif %}
 
+{%- if remove_before_start %}
+ExecStartPre=-/usr/bin/docker {{ docker_prestart_remove_command }}
+{%- endif %}
 ExecStart=/usr/bin/docker {{ docker_start_command }}
 ExecStop=/usr/bin/docker {{ docker_stop_command }}
 {%- if remove_on_stop %}

docker/files/upstart.conf

@@ -11,13 +11,20 @@ respawn
 {%- set cmd = container.get("cmd", "") %}
 
 {%- set pull_before_start = container.get("pull_before_start") or False %}
+{%- set remove_before_start = container.get("remove_before_start") or False %}
 
 {%- if pull_before_start %}
 pre-start script
   /usr/bin/docker pull {{ container.image }}
 end script
 {%- endif %}
 
+{%- if remove_before_start %}
+pre-start script
+  /usr/bin/docker rm -f {{ name }}
+end script
+{%- endif %}
+
 script
   exec docker {{ docker_start_command }}
 end script

pillar.example

@@ -14,6 +14,8 @@ docker-containers:
       # Pull image on service restart
       # (useful if you override the same tag.  example: latest)
       pull_before_start: true
+      # Remove container on service start
+      remove_before_start: false
       # Do not force container removal on stop (unless true)
       remove_on_stop: false
       runoptions:
@@ -38,6 +40,8 @@ docker-containers:
       # Pull image on service restart
       # (useful if you override the same tag. example: latest)
       pull_before_start: true
+      # Remove container on service start
+      remove_before_start: false
       # Do not force container removal on stop (unless true)
       remove_on_stop: false
       runoptions: