Code cleanup and tests

.travis.yml

@@ -20,7 +20,9 @@ before_install:
     - git --version
 after_success:
     - coveralls
-sudo: false
+sudo: required
+services:
+    - docker
 cache:
     directories:
         - $HOME/.cache/pip

CONTRIBUTING.md

@@ -2,7 +2,7 @@
 
 ## Local development
 
-- The tests depend on having at least the following installed (possibly not
+- The complete test suite depends on having at least the following installed (possibly not
   a complete list)
   - git (A sufficiently newer version is required to run pre-push tests)
   - python
@@ -10,6 +10,7 @@
   - python3.5 (Required by a test which checks different python versions)
   - tox (or virtualenv)
   - ruby + gem
+  - docker
 
 ### Setting up an environemnt
 
@@ -63,7 +64,7 @@ function_call(
 ```
 
 Some notable features:
-- The intial parenthese is at the end of the line
+- The initial parenthesis is at the end of the line
 - Parameters are indented one indentation level further than the function name
 - The last parameter contains a trailing comma (This helps make `git blame`
   more accurate and reduces merge conflicts when adding / removing parameters).

pre_commit/languages/docker.py

@@ -1,8 +1,10 @@
+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 clean_path_on_failure
 from pre_commit.util import mkdirp
@@ -10,12 +12,11 @@ from pre_commit.xargs import xargs
 
 
 ENVIRONMENT_DIR = 'docker'
+PRE_COMMIT_LABEL = 'PRE_COMMIT'
 
 
 def md5(s):
-    m = hashlib.md5()
+    return five.to_text(hashlib.md5(s).hexdigest())
-    m.update(s)
-    return m.hexdigest()
 
 
 def docker_tag(repo_cmd_runner):
@@ -24,39 +25,62 @@ def docker_tag(repo_cmd_runner):
     ).lower()
 
 
+def docker_is_running():
+    return xargs(('docker',), ['ps'])[0] == 0
+
+
+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')
+    assert repo_cmd_runner.exists('Dockerfile'), (
-    # I don't know of anybody trying to juggle multiple docker installations
+        'No Dockerfile was found in the hook repository'
-    # so this seems sufficient
+    )
+    assert version == 'default', (
+        'Pre-commit does not support language_version for docker '
+    )
+    assert_docker_available()
+
     directory = helpers.environment_dir(ENVIRONMENT_DIR, 'default')
     mkdirp(os.path.join(repo_cmd_runner.path(), directory))
 
-    cmd = (
-        'docker', 'build', '--pull',
-        '--tag', docker_tag(repo_cmd_runner),
-        '.'
-    )
-
     # 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):
-        helpers.run_setup_cmd(repo_cmd_runner, cmd)
+        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)
+    # the docker lib doesn't return stdout on non-zero exit codes,
+    # so we run the container directly on the command line
     cmd = (
         'docker', 'run',
-        '-t',
+        '--rm',
         '-v', '{}:/src'.format(os.getcwd()),
         '--workdir', '/src',
+        '--entrypoint', hook['entry'],
         docker_tag(repo_cmd_runner)
     )
-
+    return xargs(cmd + tuple(hook['args']), file_args)
-    return xargs(
-        cmd + (hook['entry'],) + tuple(hook['args']), file_args,
-    )

testing/resources/docker_hooks_repo/Dockerfile

@@ -0,0 +1,3 @@
+FROM cogniteev/echo
+
+CMD ["echo", "This is overwritten by the hooks.yaml 'entry'"]

testing/resources/docker_hooks_repo/hooks.yaml

@@ -0,0 +1,11 @@
+-   id: docker-hook
+    name: Docker test hook
+    entry: echo
+    language: docker
+    files: \.txt$
+
+-   id: docker-hook-failing
+    name: Docker test hook with nonzero exit code
+    entry: bork
+    language: docker
+    files: \.txt$

testing/util.py

@@ -6,6 +6,7 @@ import shutil
 import jsonschema
 import pytest
 
+from pre_commit.languages.docker import docker_is_running
 from pre_commit.util import cmd_output
 from pre_commit.util import cwd
 
@@ -57,6 +58,11 @@ def cmd_output_mocked_pre_commit_home(*args, **kwargs):
     return cmd_output(*args, env=env, **kwargs)
 
 
+skipif_cant_run_docker = pytest.mark.skipif(
+    docker_is_running() is False,
+    reason='Docker isn\'t running or can\'t  be accessed'
+)
+
 skipif_slowtests_false = pytest.mark.skipif(
     os.environ.get('slowtests') == 'false',
     reason='slowtests=false',

tests/repository_test.py

@@ -29,6 +29,7 @@ from testing.fixtures import git_dir
 from testing.fixtures import make_config_from_repo
 from testing.fixtures import make_repo
 from testing.fixtures import modify_manifest
+from testing.util import skipif_cant_run_docker
 from testing.util import skipif_slowtests_false
 from testing.util import xfailif_no_pcre_support
 from testing.util import xfailif_windows_no_node
@@ -129,6 +130,29 @@ def test_versioned_python_hook(tempdir_factory, store):
     )
 
 
+@skipif_slowtests_false
+@skipif_cant_run_docker
+@pytest.mark.integration
+def test_run_a_docker_hook(tempdir_factory, store):
+    _test_hook_repo(
+        tempdir_factory, store, 'docker_hooks_repo',
+        'docker-hook',
+        ['Hello World from docker'], b'Hello World from docker\n',
+    )
+
+
+@skipif_slowtests_false
+@skipif_cant_run_docker
+@pytest.mark.integration
+def test_run_a_failing_docker_hook(tempdir_factory, store):
+    _test_hook_repo(
+        tempdir_factory, store, 'docker_hooks_repo',
+        'docker-hook-failing',
+        ['Hello World from docker'], b'',
+        expected_return_code=1
+    )
+
+
 @skipif_slowtests_false
 @xfailif_windows_no_node
 @pytest.mark.integration