Add dockerfile to image, support labels, add documentation

bootstrapvz/providers/docker/README.rst

@@ -0,0 +1,53 @@
+Docker
+======
+
+The `Docker <https://www.docker.com/>`__ provider creates a docker image
+from scratch, creates a Dockerfile for it and imports the image to a repo
+specified in the manifest.
+
+In order to reduce the size of the image, it is highly recommend
+to make use of the `minimize_size <../../plugins/minimize_size>`__ plugin.
+With optimal settings a 64-bit jessie image can be whittled down to 81.95 MB
+(built on Dec 13th 2015 with ``manifests/examples/docker/minimized-jessie.yml``).
+
+
+Manifest settings
+-----------------
+
+Provider
+~~~~~~~~
+
+-  ``repository``: Repository to which the image should be imported.
+   ``required``
+
+-  ``tag``: Name with which the image should be tagged.
+   ``required``
+
+-  ``dockerfile``: Inline dockerfile that should be appended to
+   the one created by the bootstrapper.
+   ``optional``
+
+-  ``labels``: Labels that should be added to the dockerfile.
+   The image name specified at the top of the manifest
+   will be added as the label ``name``.
+   Check out the `docker docs <https://docs.docker.com/engine/userguide/labels-custom-metadata/>`__
+   for more information about custom labels.
+   `Project atomic <http://www.projectatomic.io/>`__
+   also has some `useful recommendations <https://github.com/projectatomic/ContainerApplicationGenericLabels>`__
+   for generic container labels.
+   ``optional``
+   ``manifest vars``
+
+Example:
+
+.. code:: yaml
+
+    ---
+    provider:
+      name: docker
+      repository: bootstrap-vz
+      tag: latest
+      dockerfile: >
+        CMD /bin/bash
+      labels:
+        description: Debian {system.release} {system.architecture}

bootstrapvz/providers/docker/__init__.py

@@ -25,6 +25,8 @@ def resolve_tasks(taskset, manifest):
 	taskset.update(task_groups.cleanup_group)
 
 	taskset.update([tasks.commands.AddRequiredCommands,
+	                tasks.image.PopulateDockerfileLabels,
+	                tasks.image.CreateDockerfile,
 	                tasks.image.CreateImage,
 	                ])
 

bootstrapvz/providers/docker/manifest-schema.yml

@@ -10,6 +10,21 @@ properties:
         type: string
       tag:
         type: string
+      labels:
+        type: object
+        properties:
+          # https://github.com/projectatomic/ContainerApplicationGenericLabels
+          distribution-scope:
+            type: string
+            enum:
+              - private
+              - authoritative-source-only
+              - restricted
+              - public
+          patternProperties:
+            ^.+$: {type: string}
+      dockerfile:
+        type: string
     required: [repository, tag]
   system:
     type: object

bootstrapvz/providers/docker/tasks/image.py

@@ -3,16 +3,62 @@ from bootstrapvz.common import phases
 from bootstrapvz.common.tools import log_check_call
 
 
+class PopulateDockerfileLabels(Task):
+	description = 'Populating dockerfile labels'
+	phase = phases.image_registration
+
+	@classmethod
+	def run(cls, info):
+		import pyrfc3339
+		from datetime import datetime
+		import pytz
+		labels = {}
+		labels['name'] = info.manifest.name.format(**info.manifest_vars)
+		# Inspired by https://github.com/projectatomic/ContainerApplicationGenericLabels
+		# See here for the discussion on the debian-cloud mailing list
+		# https://lists.debian.org/debian-cloud/2015/05/msg00071.html
+		labels['architecture'] = info.manifest.system['architecture']
+		labels['build-date'] = pyrfc3339.generate(datetime.utcnow().replace(tzinfo=pytz.utc))
+		if 'labels' in info.manifest.provider:
+			for label, value in info.manifest.provider['labels'].items():
+				labels[label] = value.format(**info.manifest_vars)
+		info._docker['dockerfile_labels'] = labels
+
+
+class CreateDockerfile(Task):
+	description = 'Creating dockerfile'
+	phase = phases.image_registration
+	predecessors = [PopulateDockerfileLabels]
+
+	@classmethod
+	def run(cls, info):
+		# pipes.quote converts newlines into \n rather than just prefixing
+		# it with a backslash, so we need to escape manually
+		def escape(value):
+			value = value.replace('"', '\\"')
+			value = value.replace('\n', '\\\n')
+			value = '"' + value + '"'
+			return value
+		labels = []
+		for label, value in info._docker['dockerfile_labels'].items():
+			labels.append(label + '=' + escape(value))
+		# Add some nice newlines and indentation
+		info._docker['dockerfile'] = 'LABEL ' + ' \\\n      '.join(labels) + '\n'
+		if 'dockerfile' in info.manifest.provider:
+			info._docker['dockerfile'] += info.manifest.provider['dockerfile'] + '\n'
+
+
 class CreateImage(Task):
 	description = 'Creating docker image'
 	phase = phases.image_registration
+	predecessors = [CreateDockerfile]
 
 	@classmethod
 	def run(cls, info):
 		from pipes import quote
 		tar_cmd = ['tar', '--create', '--numeric-owner',
 		           '--directory', info.volume.path, '.']
-		docker_cmd = ['docker', 'import', '-',
+		docker_cmd = ['docker', 'import', '--change', info._docker['dockerfile'], '-',
 		              info.manifest.provider['repository'] + ':' + info.manifest.provider['tag']]
 		cmd = ' '.join(map(quote, tar_cmd)) + ' | ' + ' '.join(map(quote, docker_cmd))
 		[info._docker['container_id']] = log_check_call(cmd, shell=True)

manifests/examples/docker/minimized-jessie.yml

@@ -4,6 +4,10 @@ provider:
   name: docker
   repository: bootstrap-vz
   tag: latest
+  labels:
+    description: Debian {system.release} {system.architecture}
+  dockerfile: >
+    CMD /bin/bash
 bootstrapper:
   workspace: /target
   variant: minbase

setup.py

@@ -25,6 +25,7 @@ setup(name='bootstrap-vz',
                         'pyyaml >= 3.10',
                         'boto >= 2.14.0',
                         'docopt >= 0.6.1',
+                        'pyrfc3339 >= 1.0',
                         ],
       license='Apache License, Version 2.0',
       description='Bootstrap Debian images for virtualized environments',