WIP: Starting to build puller/pusher instead of downloading

Author: gravypod

container/pull.bzl

@@ -12,6 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 "container_pull rule"
+
+load("@io_bazel_rules_go//go/private:common.bzl", "env_execute", "executable_extension")
+
 _DOC = """A repository rule that pulls down a Docker base image in a manner suitable for use with the `base` attribute of `container_image`.
 
 This is based on google/containerregistry using google/go-containerregistry.
@@ -81,30 +84,6 @@ _container_pull_attrs = {
     "platform_features": attr.string_list(
         doc = "Specifies platform features when pulling a multi-platform manifest list.",
     ),
-    "puller_darwin": attr.label(
-        executable = True,
-        default = Label("@go_puller_darwin//file:downloaded"),
-        cfg = "host",
-        doc = "Exposed to provide a way to test other pullers on macOS",
-    ),
-    "puller_linux_amd64": attr.label(
-        executable = True,
-        default = Label("@go_puller_linux_amd64//file:downloaded"),
-        cfg = "host",
-        doc = "Exposed to provide a way to test other pullers on Linux",
-    ),
-    "puller_linux_arm64": attr.label(
-        executable = True,
-        default = Label("@go_puller_linux_arm64//file:downloaded"),
-        cfg = "host",
-        doc = "Exposed to provide a way to test other pullers on Linux",
-    ),
-    "puller_linux_s390x": attr.label(
-        executable = True,
-        default = Label("@go_puller_linux_s390x//file:downloaded"),
-        cfg = "host",
-        doc = "Exposed to provide a way to test other pullers on Linux",
-    ),
     "registry": attr.string(
         mandatory = True,
         doc = "The registry from which we are pulling.",
@@ -136,18 +115,9 @@ def _impl(repository_ctx):
 
     import_rule_tags = "[\"{}\"]".format("\", \"".join(repository_ctx.attr.import_tags))
 
-    puller = repository_ctx.attr.puller_linux_amd64
-    if repository_ctx.os.name.lower().startswith("mac os"):
-        puller = repository_ctx.attr.puller_darwin
-    elif repository_ctx.os.name.lower().startswith("linux"):
-        arch = repository_ctx.execute(["uname", "-m"]).stdout.strip()
-        if arch == "arm64" or arch == "aarch64":
-            puller = repository_ctx.attr.puller_linux_arm64
-        elif arch == "s390x":
-            puller = repository_ctx.attr.puller_linux_s390x
-
+    puller = str(repository_ctx.path(Label("@rules_docker_repository_tools//:bin/puller{}".format(executable_extension(repository_ctx)))))
     args = [
-        repository_ctx.path(puller),
+        puller,
         "-directory",
         repository_ctx.path("image"),
         "-os",
@@ -211,7 +181,25 @@ def _impl(repository_ctx):
         else:
             fail("'%s' is invalid value for PULLER_TIMEOUT. Must be an integer." % (timeout_in_secs))
 
-    result = repository_ctx.execute(args, **kwargs)
+    env = {
+        # TODO(gravypod): Fix this later
+        #        k: v
+        #        for k, v in repository_ctx.os.environ
+        #        if k.lower() in [
+        #            "home",
+        #
+        #            # Used by the puller/pusher?
+        #            # TODO(gravypod): Validate that this is the case.
+        #            "ssh_auth_sock",
+        #            "ssl_cert_file",
+        #            "ssl_cert_dir",
+        #            "http_proxy",
+        #            "https_proxy",
+        #            "no_proxy",
+        #        ]
+    }
+
+    result = env_execute(repository_ctx, args, environment = env, **kwargs)
     if result.return_code:
         fail("Pull command failed: %s (%s)" % (result.stderr, " ".join([str(a) for a in args])))
 

go.sum

@@ -0,0 +1,111 @@
+# Copyright 2019 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.
+
+load("@io_bazel_rules_go//go/private:common.bzl", "env_execute", "executable_extension")
+load("@bazel_gazelle//internal:go_repository_cache.bzl", "read_cache_env")
+
+_RULES_DOCKER_TOOLS_BUILD_FILE = """
+package(default_visibility = ["//visibility:public"])
+
+filegroup(
+    name = "puller",
+    srcs = ["bin/puller{extension}"],
+)
+
+filegroup(
+    name = "pusher",
+    srcs = ["bin/pusher{extension}"],
+)
+
+exports_files(["ROOT"])
+"""
+
+def _rules_docker_repository_tools_impl(ctx):
+    # Create a link to the rules_docker repo. This will be our GOPATH.
+    env = read_cache_env(ctx, str(ctx.path(ctx.attr.go_cache)))
+    extension = executable_extension(ctx)
+    go_tool = env["GOROOT"] + "/bin/go" + extension
+
+    ctx.symlink(
+        ctx.path(Label("@io_bazel_rules_docker//:WORKSPACE")).dirname,
+        "src/github.com/bazelbuild/rules_docker",
+    )
+
+    env.update({
+        "GOPATH": str(ctx.path(".")),
+        # TODO(gravypod): make this more hermetic
+        "GO111MODULE": "off",
+        # workaround: avoid the Go SDK paths from leaking into the binary
+        "GOROOT_FINAL": "GOROOT",
+        # workaround: avoid cgo paths in /tmp leaking into binary
+        "CGO_ENABLED": "0",
+    })
+
+    if "PATH" in ctx.os.environ:
+        # workaround: to find gcc for go link tool on Arm platform
+        env["PATH"] = ctx.os.environ["PATH"]
+    if "GOPROXY" in ctx.os.environ:
+        env["GOPROXY"] = ctx.os.environ["GOPROXY"]
+
+    # Build the tools.
+    args = [
+        go_tool,
+        "install",
+        "-ldflags",
+        "-w -s",
+        "-gcflags",
+        "all=-trimpath=" + env["GOPATH"],
+        "-asmflags",
+        "all=-trimpath=" + env["GOPATH"],
+        "github.com/bazelbuild/rules_docker/container/go/cmd/puller",
+        "github.com/bazelbuild/rules_docker/container/go/cmd/pusher",
+    ]
+    result = env_execute(ctx, args, environment = env)
+    if result.return_code:
+        fail("failed to build tools: " + result.stderr)
+
+    # add a build file to export the tools
+    ctx.file(
+        "BUILD.bazel",
+        _RULES_DOCKER_TOOLS_BUILD_FILE.format(extension = executable_extension(ctx)),
+        False,
+    )
+    ctx.file(
+        "ROOT",
+        "",
+        False,
+    )
+
+rules_docker_repository_tools = repository_rule(
+    _rules_docker_repository_tools_impl,
+    attrs = {
+        "go_cache": attr.label(
+            mandatory = True,
+            allow_single_file = True,
+        ),
+    },
+    environ = [
+        "GOCACHE",
+        "GOPATH",
+        "GO_REPOSITORY_USE_HOST_CACHE",  # TODO(gravypod): Find out why this is here in rules_go
+    ],
+)
+"""go_repository_tools is a synthetic repository used by go_repository.
+
+
+go_repository depends on two Go binaries: fetch_repo and gazelle. We can't
+build these with Bazel inside a repository rule, and we don't want to manage
+prebuilt binaries, so we build them in here with go build, using whichever
+SDK rules_go is using.
+"""

internal/BUILD.bazel

@@ -21,6 +21,10 @@ repository.
 
 load("@bazel_gazelle//:deps.bzl", "gazelle_dependencies", "go_repository")
 load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_dependencies")
+load(
+    "//internal:rules_docker_repository_tools.bzl",
+    "rules_docker_repository_tools",
+)
 
 def go_deps():
     """Pull in external Go packages needed by Go binaries in this repo.
@@ -33,6 +37,11 @@ def go_deps():
     go_rules_dependencies()
     go_register_toolchains()
     gazelle_dependencies()
+
+    rules_docker_repository_tools(
+        name = "rules_docker_repository_tools",
+        go_cache = "@bazel_gazelle_go_repository_cache//:go.env",
+    )
     excludes = native.existing_rules().keys()
     if "com_github_google_go_containerregistry" not in excludes:
         go_repository(