rules_kubebuilder

These bazel rules download and make available the Kubebuilder SDK for building kubernetes operators in bazel.

To use these rules, add the following to your WORKSPACE file:

load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")

git_repository(
    name = "rules_kubebuilder",
    branch = "main",
    remote = "https://github.com/ob/rules_kubebuilder.git",
)

load("@rules_kubebuilder//kubebuilder:sdk.bzl", "kubebuilder_register_sdk")

kubebuilder_register_sdk(version = "2.3.1")

load("@rules_kubebuilder//controller-gen:deps.bzl", "controller_gen_register_toolchain")

controller_gen_register_toolchain()

load("@rules_kubebuilder//kustomize:deps.bzl", "kustomize_register_toolchain")

kustomize_register_toolchain()

And in your go_test() files, add etcd as a data dependency like this:

go_test(
    name = "go_default_test",
    srcs = ["apackage_test.go"],
    data = [
        "@kubebuilder_sdk//:bin/etcd",
    ],
    embed = [":go_default_library"],
    deps = [
    ],
)

You'll need to run the test as:

bazel test --test_env=KUBEBUILDER_ASSETS=$(bazel info execution_root 2>/dev/null)/$(bazel run @kubebuilder_sdk//:pwd 2>/dev/null) //...

You can also add the following to BUILD.bazel at the root of your workspace:

load("@rules_kubebuilder//kubebuilder:def.bzl", "kubebuilder")
kubebuilder(name = "kubebuilder")

to be able to run kubebuilder like so:

bazel run //:kubebuilder -- --help

Controller-gen

In order to use controller-gen you will need to do something like the following in your api/v1alpha1 directory (essentially where the *_type.go files are):

load("@io_bazel_rules_go//go:def.bzl", "go_library")
load(
    "@rules_kubebuilder//controller-gen:controller-gen.bzl",
    "controller_gen_crd",
    "controller_gen_object",
    "controller_gen_rbac",
)

filegroup(
    name = "srcs",
    srcs = [
        "groupversion_info.go",
        # your source files here, except for zz_generated_deepcopy.go
    ],
)

DEPS = [
    "@io_k8s_api//core/v1:go_default_library",
    "@io_k8s_apimachinery//pkg/api/resource:go_default_library",
    "@io_k8s_apimachinery//pkg/apis/meta/v1:go_default_library",
    "@io_k8s_apimachinery//pkg/runtime:go_default_library",
    "@io_k8s_apimachinery//pkg/runtime/schema:go_default_library",
    "@io_k8s_sigs_controller_runtime//pkg/scheme:go_default_library",
]

controller_gen_object(
    name = "generated_sources",
    srcs = [
        ":srcs",
    ],
    deps = DEPS,
)

# keep
go_library(
    name = "go_default_library",
    srcs = [
        "generated_sources",
        "srcs",
    ],
    importpath = "yourdomain.com/your-operator/api/v1alpha1",
    visibility = ["//visibility:public"],
    deps = DEPS,
)

controller_gen_crd(
    name = "crds",
    srcs = [
        ":srcs",
    ],
    visibility = ["//visibility:public"],
    deps = DEPS,
)

Developers

The toolchain that describes controller-gen needs to be built and the binaries committed so that they can be used. Fortunately Go supports cross compiling so in order to build the controller, you'll need to get and install Go either from their download page or from homebrew by running

brew install golang

After that you can run the script in scripts/build-controller-gen.sh which will compile controller-gen for both Linux and macOS.