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Make transitions optional
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Transitions, introduced in bazelbuild#1963 can now be disabled by calling bazel with `--@io_bazel_rules_docker//transitions:enable=no`.
Added tests to verify the behaviour.
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laurynaslubys committed Apr 24, 2022
1 parent 6ea707b commit 3af18bd
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10 changes: 8 additions & 2 deletions README.md
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Expand Up @@ -208,6 +208,12 @@ like:
Unable to load package for //:WORKSPACE: BUILD file not found in any of the following directories.
```

* rules_docker uses transitions to build your containers using toolchains the correct
architecture and operating system. If you run into issues with toolchain resolutions,
you can disable this behaviour, by adding this to your .bazelrc:
```
build --@io_bazel_rules_docker//transitions:enable=false
```
## Using with Docker locally.

Suppose you have a `container_image` target `//my/image:helloworld`:
Expand Down Expand Up @@ -635,7 +641,7 @@ nodejs_image(
name = "nodejs_image",
entry_point = "@your_workspace//path/to:file.js",
# npm deps will be put into their own layer
data = [":file.js", "@npm//some-npm-dep"],
data = [":file.js", "@npm//some-npm-dep"],
...
)
```
Expand Down Expand Up @@ -1150,7 +1156,7 @@ load("@io_bazel_rules_docker//toolchains/docker:toolchain.bzl",

docker_toolchain_configure(
name = "docker_config",
# Replace this with a Bazel label to the config.json file. Note absolute or relative
# Replace this with a Bazel label to the config.json file. Note absolute or relative
# paths are not supported. Docker allows you to specify custom authentication credentials
# in the client configuration JSON file.
# See https://docs.docker.com/engine/reference/commandline/cli/#configuration-files
Expand Down
17 changes: 14 additions & 3 deletions container/image.bzl
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Expand Up @@ -770,7 +770,15 @@ _outputs["config_digest"] = "%{name}.json.sha256"
_outputs["build_script"] = "%{name}.executable"

def _image_transition_impl(settings, attr):
return dicts.add(settings, {
if not settings["//transitions:enable"]:
# Once bazel < 5.0 is not supported we can return an empty dict here
return {
"//command_line_option:platforms": settings["//command_line_option:platforms"],
"@io_bazel_rules_docker//platforms:image_transition_cpu": "//plaftorms:image_transition_cpu_unset",
"@io_bazel_rules_docker//platforms:image_transition_os": "//plaftorms:image_transition_os_unset",
}

return {
"//command_line_option:platforms": "@io_bazel_rules_docker//platforms:image_transition",
"@io_bazel_rules_docker//platforms:image_transition_cpu": "@platforms//cpu:" + {
# Architecture aliases.
Expand All @@ -779,11 +787,14 @@ def _image_transition_impl(settings, attr):
"ppc64le": "ppc",
}.get(attr.architecture, attr.architecture),
"@io_bazel_rules_docker//platforms:image_transition_os": "@platforms//os:" + attr.operating_system,
})
}

_image_transition = transition(
implementation = _image_transition_impl,
inputs = [],
inputs = [
"//transitions:enable",
"//command_line_option:platforms",
],
outputs = [
"//command_line_option:platforms",
"@io_bazel_rules_docker//platforms:image_transition_cpu",
Expand Down
82 changes: 82 additions & 0 deletions tests/container/BUILD
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Expand Up @@ -30,6 +30,7 @@ load("//contrib:test.bzl", "container_test")
load(":apple.bzl", "create_banana_directory")
load(":empty_layers.bzl", "empty_layers")
load(":pull_info_validation_test.bzl", "pull_info_validation_test")
load(":transitions.bzl", "templated_file", "transition_test")

package(default_visibility = ["//visibility:public"])

Expand Down Expand Up @@ -999,3 +1000,84 @@ container_bundle(
"localhost:5000/image4:latest": "//testdata:with_double_label",
},
)

genrule(
name = "got_os",
outs = ["got_os.txt"],
cmd = select({
"@platforms//os:windows": "echo windows > \"$@\"",
"@platforms//os:linux": "echo linux > \"$@\"",
"@platforms//os:macos": "echo macos > \"$@\"",
}),
)

genrule(
name = "got_arch",
outs = ["got_arch.txt"],
cmd = select({
"@platforms//cpu:arm64": "echo arm64 > \"$@\"",
"@platforms//cpu:aarch64": "echo arm64 > \"$@\"",
"@platforms//cpu:x86_64": "echo x86_64 > \"$@\"",
"@platforms//cpu:arm": "echo arm > \"$@\"",
}),
)

container_image(
name = "transitioned_image",
architecture = "arm64",
files = [
":got_arch",
":got_os",
],
operating_system = "windows",
)

templated_file(
name = "transitions_on",
out = "transitions_on.yaml",
substitutions = [
"%WANT_OS%=windows",
"%WANT_ARCH%=arm64",
],
template = "//tests/container/configs:transitions.yaml.tpl",
)

templated_file(
name = "transitions_off",
out = "transitions_off.yaml",
substitutions =
select({
"@platforms//os:linux": ["%WANT_OS%=linux"],
"@platforms//os:macos": ["%WANT_OS%=macos"],
}) + select({
"@platforms//cpu:arm64": ["%WANT_ARCH%=arm64"],
"@platforms//cpu:aarch64": ["%WANT_ARCH%=arm64"],
"@platforms//cpu:x86_64": ["%WANT_ARCH%=x86_64"],
}),
template = "//tests/container/configs:transitions.yaml.tpl",
)

container_test(
name = "transition_test",
configs = select({
"//transitions:enabled": [":transitions_on"],
"//transitions:disabled": [":transitions_off"],
}),
driver = "tar",
image = ":transitioned_image",
# marked manual, because we are interested in running it with transitions
# enabled or disabled
tags = ["manual"],
)

transition_test(
name = "transitions_on_test",
actual = ":transition_test",
transitions_enabled = True,
)

transition_test(
name = "transitions_off_test",
actual = ":transition_test",
transitions_enabled = False,
)
2 changes: 1 addition & 1 deletion tests/container/configs/BUILD
Original file line number Diff line number Diff line change
Expand Up @@ -12,4 +12,4 @@
# See the License for the specific language governing permissions and
# limitations under the License.

exports_files(glob(["*.yaml"]))
exports_files(glob(["*.yaml"]) + glob(["*.yaml.tpl"]))
9 changes: 9 additions & 0 deletions tests/container/configs/transitions.yaml.tpl
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@@ -0,0 +1,9 @@
schemaVersion: 2.0.0

fileContentTests:
- name: "validate architecture"
path: "/Files/got_arch.txt"
expectedContents: ["%WANT_ARCH%"]
- name: "validate os"
path: "/Files/got_os.txt"
expectedContents: ["%WANT_OS%"]
77 changes: 77 additions & 0 deletions tests/container/transitions.bzl
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@@ -0,0 +1,77 @@
"""
Rules for running tests with a specific value of the //transitions:enabled flag
"""

def _templated_file_impl(ctx):
out = ctx.outputs.out
ctx.actions.expand_template(
template = ctx.file.template,
output = out,
substitutions = dict([s.split("=", 1) for s in ctx.attr.substitutions]),
)
return DefaultInfo(
files = depset([out]),
)

# Replaces substitutions split on `=` in the template. Substitution is a list
# so that is usable with multiple selects,
templated_file = rule(
attrs = {
"template": attr.label(
mandatory = True,
allow_single_file = True,
),
"substitutions": attr.string_list(),
"out": attr.output(),
},
implementation = _templated_file_impl,
)

def _enable_transition_impl(settings, attr):
_ = settings
return {"//transitions:enable": attr.transitions_enabled}

_enable_transition = transition(
implementation = _enable_transition_impl,
inputs = [],
outputs = [
"//transitions:enable",
],
)

def _transitioned_test(ctx):
source_info = ctx.attr.actual[DefaultInfo]

# Bazel wants the executable to be generated by this rule, let's oblige by
# just copying the actual runner.
executable = None
if source_info.files_to_run and source_info.files_to_run.executable:
executable = ctx.actions.declare_file("{}_{}".format(ctx.file.actual.basename, "on" if ctx.attr.transitions_enabled else "off"))
ctx.actions.run_shell(
command = "cp {} {}".format(source_info.files_to_run.executable.path, executable.path),
inputs = [source_info.files_to_run.executable],
outputs = [executable],
)
return [DefaultInfo(
files = depset(ctx.files.actual),
runfiles = source_info.default_runfiles.merge(source_info.data_runfiles),
executable = executable,
)]

# Defines a test that runs with a specific value of the //transitions:enable
# flag.
transition_test = rule(
attrs = {
"actual": attr.label(
mandatory = True,
allow_single_file = True,
),
"transitions_enabled": attr.bool(),
"_allowlist_function_transition": attr.label(
default = "@bazel_tools//tools/allowlists/function_transition_allowlist",
),
},
cfg = _enable_transition,
test = True,
implementation = _transitioned_test,
)
31 changes: 31 additions & 0 deletions transitions/BUILD
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@@ -0,0 +1,31 @@
# Copyright 2022 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("@bazel_skylib//rules:common_settings.bzl", "bool_flag")

package(
default_visibility = ["//visibility:public"],
)

bool_flag(name = "enable", build_setting_default=True)

config_setting(
name = "enabled",
flag_values = {"//transitions:enable": "true"}
)

config_setting(
name = "disabled",
flag_values = {"//transitions:enable": "false"}
)

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