Merge pull request #459 from bpicolo/docker_support

Docker hook support for pre-commit

pre_commit/languages/all.py

@@ -1,5 +1,6 @@
 from __future__ import unicode_literals
 
+from pre_commit.languages import docker
 from pre_commit.languages import node
 from pre_commit.languages import pcre
 from pre_commit.languages import python
@@ -40,6 +41,7 @@ from pre_commit.languages import system
 #     """
 
 languages = {
+    'docker': docker,
     'node': node,
     'pcre': pcre,
     'python': python,

pre_commit/languages/docker.py

@@ -0,0 +1,90 @@
+from __future__ import absolute_import
+from __future__ import unicode_literals
+
+import hashlib
+import os
+
+from pre_commit import five
+from pre_commit.languages import helpers
+from pre_commit.util import CalledProcessError
+from pre_commit.util import clean_path_on_failure
+from pre_commit.util import cmd_output
+from pre_commit.xargs import xargs
+
+
+ENVIRONMENT_DIR = 'docker'
+PRE_COMMIT_LABEL = 'PRE_COMMIT'
+
+
+def md5(s):
+    return hashlib.md5(five.to_bytes(s)).hexdigest()
+
+
+def docker_tag(repo_cmd_runner):
+    return 'pre-commit-{}'.format(
+        md5(os.path.basename(repo_cmd_runner.path()))
+    ).lower()
+
+
+def docker_is_running():
+    try:
+        return cmd_output('docker', 'ps')[0] == 0
+    except CalledProcessError:
+        return False
+
+
+def assert_docker_available():
+    assert docker_is_running(), (
+        'Docker is either not running or not configured in this environment'
+    )
+
+
+def build_docker_image(repo_cmd_runner):
+    cmd = (
+        'docker', 'build', '--pull',
+        '--tag', docker_tag(repo_cmd_runner),
+        '--label', PRE_COMMIT_LABEL,
+        '.'
+    )
+    helpers.run_setup_cmd(repo_cmd_runner, cmd)
+
+
+def install_environment(
+        repo_cmd_runner,
+        version='default',
+        additional_dependencies=(),
+):
+    assert repo_cmd_runner.exists('Dockerfile'), (
+        'No Dockerfile was found in the hook repository'
+    )
+    assert version == 'default', (
+        'Pre-commit does not support language_version for docker '
+    )
+    assert_docker_available()
+
+    directory = helpers.environment_dir(ENVIRONMENT_DIR, 'default')
+    os.mkdir(repo_cmd_runner.path(directory))
+
+    # Docker doesn't really have relevant disk environment, but pre-commit
+    # still needs to cleanup it's state files on failure
+    env_dir = repo_cmd_runner.path(directory)
+    with clean_path_on_failure(env_dir):
+        build_docker_image(repo_cmd_runner)
+
+
+def run_hook(repo_cmd_runner, hook, file_args):
+    assert_docker_available()
+    # Rebuild the docker image in case it has gone missing, as many people do
+    # automated cleanup of docker images.
+    build_docker_image(repo_cmd_runner)
+    cmd = (
+        'docker', 'run',
+        '--rm',
+        '-u', '{}:{}'.format(os.getuid(), os.getgid()),
+        '-v', '{}:/src:rw'.format(os.getcwd()),
+        '--workdir', '/src',
+        '--entrypoint', hook['entry'],
+        docker_tag(repo_cmd_runner)
+    )
+
+    return xargs(cmd + tuple(hook['args']), file_args)