recipe_modules/docker/api.py

# Copyright 2019 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

from recipe_engine import recipe_api

from contextlib import contextmanager


class DockerApi(recipe_api.RecipeApi):
    """Provides steps to connect and run Docker images."""

    def __init__(self, luci_context, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._luci_context = luci_context

    def __call__(self, *args, **kwargs):
        """Executes specified docker command.

        Please make sure to use api.docker.login method before if specified command
        requires authentication.

        Args:
          args: arguments passed to the 'docker' command including subcommand name,
              e.g. api.docker('push', 'my_image:latest').
          kwargs: arguments passed down to api.step module.
        """
        cmd = ["docker"]
        step_name = kwargs.pop("step_name", "docker %s" % args[0])
        return self.m.step(step_name, cmd + list(args), **kwargs)

    def build(
        self, dockerfile, tags=(), build_args=(), docker_args=(), cache_from=None
    ):
        """Build docker image based on dockerfile.

        E.g.with api.context(cwd=working_dir):
              api.docker.build(dockerfile,
                               [ 'gcr.io/goma-fuchsia/fuchsia_linux/clang-r101' ],
                               'gcr.io/goma-fuchsia/fuchsia_linux/clang-r101')

            will build docker image from 'dockerfile', using
            'gcr.io/goma-fuchsia/fuchsia_linux/clang-r101' image as
            cache and tag it with 'gcr.io/goma-fuchsia/fuchsia_linux/clang-r101'
            Please note, due to limitation of docker, dockerfile must located
            within the working_dir or its subdirectories.

        Args:
          * dockerfile (str) - The path to the dockerfile.
          * tags (list(str)) - The list of tags need to be put on built image.
          * build_args (list(str)) - The list of build args.
          * cache_from (str) - The tag to the cache image. It's optional.
        """
        args = [
            "build",
            "--file=%s" % dockerfile,
        ]
        args.extend(docker_args)
        if cache_from:
            args.append("--cache-from=%s" % cache_from)
        for tag in tags:
            args.append("--tag=%s" % tag)
        for build_arg in build_args:
            args.extend(["--build-arg", build_arg])
        args.append(self.m.context.cwd)
        name = tags[0] if tags else dockerfile
        self(*args, step_name="docker build %s" % name)

    @contextmanager
    def create(self, tag, name=""):
        """Make context wrapping of creating docker container and returns the name of
        the created container.

        E.g. with create(tag, name='optional-name') as container:
               api.docker.copy(container, ['path/inside/container'], api.path)

        Args:
          * tag (str) - The tag of the docker image.
          * name (str) - Optional name of the created container.
        """
        try:
            self("pull", tag, step_name="pull docker image %s" % tag)
            args = ["create"]
            if name:
                args.extend(["--name", name])
            args.extend([tag])
            container_id = self(
                *args, stdout=self.m.raw_io.output_text()
            ).stdout.strip()
            yield container_id
        finally:
            self(
                "rm",
                "-fv",
                container_id,
                step_name="remove %s container" % container_id,
            )

    def copy(self, name, file_list, target_dir):
        """Copy files from a docker container.

        E.g. copy(
                 'gomatools',
                 ['/opt/goma/bin/setup_cmd'],
                 api.path['cleanup'])
            will copy file '/opt/goma/bin/setup_cmd' from container 'gomatools' and
            save it to api.path['cleanup'] directory.

        Args:
          * name (str) - The name of the docker container.
          * file_list (list(str)) - The list of files need to be copied.
          * target_dir (Path) - The target path.
        """
        with self.m.step.nest("copy file from container %s" % name):
            target_dir = str(target_dir)
            if not target_dir:
                target_dir = "./"
            if target_dir[-1] != "/":
                target_dir = target_dir + "/"
            for item in file_list:
                self(
                    "cp", "%s:%s" % (name, item), target_dir, step_name="copy %s" % item
                )

    def cleanup(self):
        """Clean up storage resources used by docker."""
        self("system", "prune", "-f", "-a", step_name="docker cleanup")

    def run(
        self,
        image,
        cmd_args=(),
        dir_mapping=None,
        env=None,
        cwd=None,
        inherit_luci_context=False,
        **kwargs,
    ):
        """Run a command in a Docker image as the current user:group.

        Args:
          image (str): Name of the image to run, including version tag.
          cmd_args (seq[str]): Used to specify command to run in an image as a list of
              arguments. If not specified, then the default command embedded into
              the image is executed.
          dir_mapping (seq[tuple]): List of tuples (host_dir, docker_dir) mapping host
              directories to directories in a Docker container. Directories are
              mapped as read-write.
          env (dict[str]str) : dict of env variables.
          cwd (str): Path to the working directory for the container.
          inherit_luci_context (bool): Inherit current LUCI Context (including auth).
              CAUTION: removes network isolation between the container and the
              docker host. Read more https://docs.docker.com/network/host/.
        """
        args = ["run"]

        if dir_mapping:
            for host_dir, docker_dir in dir_mapping:
                # Ensure that host paths exist, otherwise they will be created by the docker
                # command, which makes them owned by root and thus hard to remove/modify.
                if not self.m.path.exists(host_dir):
                    self.m.file.ensure_directory("host dir", host_dir)
                args.extend(
                    [
                        "--mount",
                        "type=bind,source=%s,destination=%s" % (host_dir, docker_dir),
                    ]
                )

        if env:
            for k, v in sorted((env or {}).items()):
                args.extend(["--env", "%s=%s" % (k, v)])
        if cwd:
            args.extend(
                [
                    "-w",
                    cwd,
                ]
            )
        if inherit_luci_context:
            assert self.m.platform.is_linux, "supported only on Linux"

            if not self._luci_context:  # pragma: no cover
                raise self.m.step.InfraFailure("$LUCI_CONTEXT is not set or empty")

            args.extend(
                [
                    # Map the temp file to /tmp/luci_context inside the container.
                    "--volume",
                    "%s:/tmp/luci_context:ro" % self._luci_context,
                    # Set LUCI_CONTEXT variable pointing to /tmp/luci_context.
                    "--env",
                    "LUCI_CONTEXT=/tmp/luci_context",
                    # Remove network isolation, so the container can talk to auth server.
                    "--network",
                    "host",
                ]
            )

        args.append(image)
        args.extend(cmd_args)

        return self(*args, **kwargs)