base/docker_pull.bzl

# Copyright 2016 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Quick and not really nice docker_pull rules based on the docker daemon."""

def _impl(repository_ctx):
  repository_ctx.file("BUILD", """
load("@io_bazel_rules_docker//docker:docker.bzl", "docker_build")

docker_build(
    name = "image",
    base = ":base.tar",
    visibility = ["//visibility:public"],
)
""")
  tag = repository_ctx.attr.tag
  if repository_ctx.attr.dockerfile:
    dockerfile = repository_ctx.path(repository_ctx.attr.dockerfile)
    result = repository_ctx.execute([
        "docker",
        "build",
        "-q",
        "-t",
        tag,
        "-f",
        dockerfile,
        dockerfile.dirname,
    ])
  else:
    result = repository_ctx.execute(["docker", "pull", tag])
  if result.return_code:
    fail("docker build failed with error code %s:\n%s" % (
        result.return_code,
        result.stdout + result.stderr))
  result = repository_ctx.execute([
      "docker", "save", "-o", repository_ctx.path("base.tar"), tag])
  if result.return_code:
    fail("docker save failed with error code %s:\n%s" % (
        result.return_code,
        result.stderr))

docker_pull = repository_rule(
    implementation = _impl,
    attrs = {
        "tag": attr.string(mandatory=True),
        "dockerfile": attr.label(default=None),
    },
)