Merge pull request #500 from jrbourbeau/add-labels

Add repo2docker Dockerfile labels

CHANGES.rst

@@ -5,6 +5,8 @@ Release date: the-future
 
 New features
 ------------
+- Add additional metadata to docker images about how they were built `#500`_ by
+  `@jrbourbeau`_.
 
 API changes
 -----------
@@ -99,6 +101,7 @@ Released 2017-04-14
 .. _#475: https://github.com/jupyter/repo2docker/pull/475
 .. _#478: https://github.com/jupyter/repo2docker/pull/478
 .. _#482: https://github.com/jupyter/repo2docker/pull/482
+.. _#500: https://github.com/jupyter/repo2docker/pull/500
 
 .. _@agahkarakuzu: https://github.com/agahkarakuzu
 .. _@betatim: https://github.com/betatim
@@ -107,6 +110,7 @@ Released 2017-04-14
 .. _@costrouc: https://github.com/costrouc
 .. _@dsludwig: https://github.com/dsludwig
 .. _@evertrol: https://github.com/evertrol
+.. _@jrbourbeau: https://github.com/jrbourbeau
 .. _@minrk: https://github.com/minrk
 .. _@nuest: https://github.com/nuest
 .. _@yuvipanda: https://github.com/yuvipanda

repo2docker/app.py

@@ -745,6 +745,11 @@ class Repo2Docker(Application):
                     picked_buildpack = self.default_buildpack()
 
                 picked_buildpack.appendix = self.appendix
+                # Add metadata labels
+                picked_buildpack.labels['repo2docker.version'] = self.version
+                repo_label = 'local' if os.path.isdir(self.repo) else self.repo
+                picked_buildpack.labels['repo2docker.repo'] = repo_label
+                picked_buildpack.labels['repo2docker.ref'] = self.ref
 
                 self.log.debug(picked_buildpack.render(),
                                extra=dict(phase='building'))

repo2docker/buildpacks/base.py

@@ -120,8 +120,8 @@ ENV {{item[0]}} {{item[1]}}
 # Container image Labels!
 # Put these at the end, since we don't want to rebuild everything
 # when these change! Did I mention I hate Dockerfile cache semantics?
-{% for k, v in labels.items() -%}
-LABEL {{k}}={{v}}
+{% for k, v in labels.items() %}
+LABEL {{k}}="{{v}}"
 {%- endfor %}
 
 # We always want containers to run as non-root
@@ -171,6 +171,7 @@ class BuildPack:
     def __init__(self):
         self.log = logging.getLogger('repo2docker')
         self.appendix = ''
+        self.labels = {}
         if sys.platform.startswith('win'):
             self.log.warning("Windows environment detected. Note that Windows "
                              "support is experimental in repo2docker.")
@@ -246,7 +247,7 @@ class BuildPack:
         """
         Docker labels to set on the built image.
         """
-        return {}
+        return self.labels
 
     def get_build_script_files(self):
         """

tests/test_labels.py

@@ -0,0 +1,52 @@
+"""
+Test if labels are supplied correctly to the container
+"""
+from repo2docker.app import Repo2Docker
+from repo2docker.buildpacks import BuildPack
+from repo2docker import __version__
+import pytest
+from unittest.mock import Mock
+
+
+URL = "https://github.com/binderhub-ci-repos/repo2docker-ci-clone-depth"
+
+
+def test_buildpack_labels_rendered():
+    bp = BuildPack()
+    assert 'LABEL' not in bp.render()
+    bp.labels['first_label'] = 'firstlabel'
+    assert 'LABEL first_label="firstlabel"\n' in bp.render()
+    bp.labels['second_label'] = 'anotherlabel'
+    assert 'LABEL second_label="anotherlabel"\n' in bp.render()
+
+
+@pytest.mark.parametrize('ref, repo, expected_repo_label', [
+    (None, URL, URL),
+    ('some-ref', None, 'local'),
+    (None, None, 'local'),
+])
+def test_Repo2Docker_labels(ref, repo, expected_repo_label, tmpdir):
+    if repo is None:
+        repo = str(tmpdir)
+    if ref is not None:
+        argv = ['--ref', ref, repo]
+    else:
+        argv = [repo]
+
+    app = Repo2Docker()
+    # Add mock BuildPack to app
+    mock_buildpack = Mock()
+    mock_buildpack.return_value.labels = {}
+    app.buildpacks = [mock_buildpack]
+
+    app.initialize(argv)
+    app.build = False
+    app.run = False
+    app.start()
+    expected_labels = {
+        'repo2docker.ref': ref,
+        'repo2docker.repo': expected_repo_label,
+        'repo2docker.version': __version__,
+    }
+
+    assert mock_buildpack().labels == expected_labels