bzl

README

bzl

bzl is a command-line application that makes it easier to work with multiple versions of bazel. You can install different versions and easily switch between them.

bzl is a drop-in replacement for bazel. Any commands not recognized by bzl are passed through as-is to bazel.

How is bzl pronounced?

bzl is pronounced like bezel, as in "the bezel of a watch". The name invokes it's function (a wrapper around bazel).

In the 1950s, watchmakers realized that an external bezel was the best way to add functions to a watch without complicating the movement, and so the external watch bezel was born.

Install bzl

bzl ships as a single executable go binary. Download the file directly from the Github Releases Page for the precompiled platform of your choice (or build from source).

Once downloaded chmod +x and mv bzl ~/bin/bazel and type bazel install to list the available versions.

Specify the version of bazel to use either via an environment variable or command line flag (example: BAZEL_VERSION=0.24.1; --bazel=0.19.2).

bzl commands

$ bazel --help

Show help.

$ bazel install

List or install available bazel installs.

Examples:

Command	Description
$ bazel install	List all available releases
$ bazel install 0.8.0	Install bazel release 0.8.0
$ bazel install --list 0.8.0	Show the assets bundled in install 0.8.0

$ bazel use

Print a repository rule for a github bazel repository.

Without a release tag, list available releases:

$ bazel use grpc-ecosystem/grpc-gateway 

v1.8.5        Fri Mar 15 2019
v1.8.4        Wed Mar 13 2019
v1.8.3        Mon Mar 11 2019
v1.8.2        Thu Mar 07 2019
v1.8.1        Sat Mar 02 2019

With a release tag, output an http_archive rule:

$ bazel use grpc-ecosystem/grpc-gateway v1.8.5

http_archive(
    name = "grpc_ecosystem_grpc_gateway",
    urls = ["https://github.com/grpc-ecosystem/grpc-gateway/archive/v1.8.5.tar.gz"],
    strip_prefix = "grpc-gateway-1.8.5",
    sha256 = "9d7cf2ce799002024f215d3ff2df4882c347563478093a4671b13154ba37982c",
)

The bazelbuild organization is assumed if you leave out the organization name:

$ bazel use rules_go

0.18.3    Fri Apr 12 2019
0.17.4    Fri Apr 12 2019
0.16.10   Fri Apr 12 2019
0.18.2    Sat Apr 06 2019
...

$ bazel target

Pretty-print available targets in the current workspace.

Example:

$ bazel targets

go_library        rule  //proto/bes:go_default_library
go_library        rule  //:go_default_library
go_library        rule  //command:go_default_library
go_library        rule  //command/targets:go_default_library
_gazelle_runner   rule  //:gazelle-runner
go_library        rule  //gh:go_default_library
go_proto_library  rule  //proto/bes:build_event_stream_go_proto
proto_library     rule  //proto/build:bzl_proto
proto_library     rule  //proto/bes:build_event_stream_proto
go_proto_library  rule  //proto/build:bzl_go_proto
go_library        rule  //command/release:go_default_library
sh_binary         rule  //:gazelle
go_library        rule  //command/install:go_default_library
go_library        rule  //config:go_default_library
go_test           rule  //:go_default_test
go_library        rule  //proto/build:go_default_library
go_library        rule  //bazelutil:go_default_library
go_binary         rule  //:bzl
go_library        rule  //command/use:go_default_library
_buildifier       rule  //:buildifier

$ bazel release

Publish a release for a go_binary target.

This is a simple variant of the "goreleaser" tool for go binaries built by rules_go. Here's what the command does:

1. Reads the name of a go_binary target (example: //:bzl) as the first command line argument.
2. Takes a list of platform names via the --platform argument (example: linux_amd64) it runs the equivalent of bazel build --platforms @io_bazel_rules_go//go/toolchain:linux_amd64
3. Copies the output file to {ASSET_DIR}/{LABEL_NAME}-{TAG}-{PLATFORM_NAME} (example: .assets/bzl-v0.1.3-linux-x64_64) where --asset_dir={ASSET_DIR}, --tag={TAG}, and --platform={PLATFORM}. The {PLATFORM_NAME} can be remapped to a different string via --platform_name={PLATFORM}=NAME (example: windows_amd64=windows-x64_64).
4. Reads a release notes file (example: --notes=RELEASE.md).
5. Uploads the staged assets to github. Authentication is via environment variables (example: BZL_GH_USERNAME=pcj BZL_GH_PASSWORD={PERSONAL_ACCESS_TOKEN})
6. Tags the release as --tag={TAG}.

Example:

$ bazel release \
    --owner=bzl-io \
    --repo=bzl \
    --commit=91801a92ea21cd73471e5a83ad2519d1a3f257f0 \
    --tag=v0.1.3 \
    --notes=RELEASE.md \
    --platform=linux_amd64 \
    --platform=darwin_amd64 \
    --platform=windows_amd64 \
    //:bzl