✨ v3: rewrite to work the same as kubernetes code-generator

.gitignore

@@ -4,7 +4,7 @@
 *.dll
 *.so
 *.dylib
-/bin
+/_build
 
 # Test binary, built with `go test -c`
 *.test
@@ -14,17 +14,7 @@
 
 # Dependency directories
 vendor/
+hack/tools/
 
 # IDE files
 .idea
-
-hack/tools
-
-examples/bin/applyconfiguration-gen
-examples/bin/client-gen
-examples/bin/conversion-gen
-examples/bin/deepcopy-gen
-examples/bin/defaulter-gen
-examples/bin/informer-gen
-examples/bin/lister-gen
-examples/bin/openapi-gen

.golangci.yaml

@@ -10,11 +10,11 @@ linters:
   - bidichk
   - bodyclose
   - containedctx
+  - copyloopvar
   - dupword
   - durationcheck
   - errcheck
   - errchkjson
-  - exportloopref
   - gocritic
   - godot
   - gofmt
@@ -29,10 +29,17 @@ linters:
   - noctx
   - nolintlint
   - nosprintfhostport
-  - prealloc
   - revive
   - staticcheck
   - unconvert
   - unused
   - usestdlibvars
   - whitespace
+
+linters-settings:
+  revive:
+    rules:
+    # That is just how the Kubernetes code-generators are written.
+    # We'd rather stay closer to upstream than fixing this.
+    - name: unexported-return
+      disabled: true

Makefile

@@ -1,4 +1,4 @@
-# Copyright 2022 The KCP Authors.
+# Copyright 2025 The KCP Authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -15,38 +15,18 @@
 SHELL := /usr/bin/env bash
 
 GO_INSTALL = ./hack/go-install.sh
+BUILD_DEST ?= _build
+BUILDFLAGS ?=
+CMD ?= $(notdir $(wildcard ./cmd/*))
 
 TOOLS_DIR=hack/tools
 GOBIN_DIR := $(abspath $(TOOLS_DIR))
 TMPDIR := $(shell mktemp -d)
 
-CONTROLLER_GEN_VER := v0.17.0
-CONTROLLER_GEN_BIN := controller-gen
-CONTROLLER_GEN := $(GOBIN_DIR)/$(CONTROLLER_GEN_BIN)-$(CONTROLLER_GEN_VER)
-export CONTROLLER_GEN
-
 GOLANGCI_LINT_VER := v1.62.2
 GOLANGCI_LINT_BIN := golangci-lint
 GOLANGCI_LINT := $(GOBIN_DIR)/$(GOLANGCI_LINT_BIN)-$(GOLANGCI_LINT_VER)
 
-KUBE_CLIENT_GEN_VER := v0.32.3
-KUBE_CLIENT_GEN_BIN := client-gen
-KUBE_LISTER_GEN_VER := v0.32.3
-KUBE_LISTER_GEN_BIN := lister-gen
-KUBE_INFORMER_GEN_VER := v0.32.3
-KUBE_INFORMER_GEN_BIN := informer-gen
-KUBE_APPLYCONFIGURATION_GEN_VER := v0.32.3
-KUBE_APPLYCONFIGURATION_GEN_BIN := applyconfiguration-gen
-
-KUBE_CLIENT_GEN := $(GOBIN_DIR)/$(KUBE_CLIENT_GEN_BIN)-$(KUBE_CLIENT_GEN_VER)
-export KUBE_CLIENT_GEN
-KUBE_LISTER_GEN := $(GOBIN_DIR)/$(KUBE_LISTER_GEN_BIN)-$(KUBE_LISTER_GEN_VER)
-export KUBE_LISTER_GEN
-KUBE_INFORMER_GEN := $(GOBIN_DIR)/$(KUBE_INFORMER_GEN_BIN)-$(KUBE_INFORMER_GEN_VER)
-export KUBE_INFORMER_GEN
-KUBE_APPLYCONFIGURATION_GEN := $(GOBIN_DIR)/$(KUBE_APPLYCONFIGURATION_GEN_BIN)-$(KUBE_APPLYCONFIGURATION_GEN_VER)
-export KUBE_APPLYCONFIGURATION_GEN
-
 OPENSHIFT_GOIMPORTS_VER := c70783e636f2213cac683f6865d88c5edace3157
 OPENSHIFT_GOIMPORTS_BIN := openshift-goimports
 OPENSHIFT_GOIMPORTS := $(TOOLS_DIR)/$(OPENSHIFT_GOIMPORTS_BIN)-$(OPENSHIFT_GOIMPORTS_VER)
@@ -60,30 +40,26 @@ imports: $(OPENSHIFT_GOIMPORTS)
 	$(OPENSHIFT_GOIMPORTS) --path ./examples -m acme.corp
 .PHONY: imports
 
-$(CONTROLLER_GEN):
-	GOBIN=$(GOBIN_DIR) $(GO_INSTALL) sigs.k8s.io/controller-tools/cmd/$(CONTROLLER_GEN_BIN) $(CONTROLLER_GEN_BIN) $(CONTROLLER_GEN_VER)
+.PHONY: clean
+clean:
+	rm -rf $(BUILD_DEST)
+	@echo "Cleaned $(BUILD_DEST)"
 
-$(KUBE_CLIENT_GEN):
-	GOBIN=$(GOBIN_DIR) $(GO_INSTALL) k8s.io/code-generator/cmd/$(KUBE_CLIENT_GEN_BIN) $(KUBE_CLIENT_GEN_BIN) $(KUBE_CLIENT_GEN_VER)
-$(KUBE_LISTER_GEN):
-	GOBIN=$(GOBIN_DIR) $(GO_INSTALL) k8s.io/code-generator/cmd/$(KUBE_LISTER_GEN_BIN) $(KUBE_LISTER_GEN_BIN) $(KUBE_LISTER_GEN_VER)
-$(KUBE_INFORMER_GEN):
-	GOBIN=$(GOBIN_DIR) $(GO_INSTALL) k8s.io/code-generator/cmd/$(KUBE_INFORMER_GEN_BIN) $(KUBE_INFORMER_GEN_BIN) $(KUBE_INFORMER_GEN_VER)
-$(KUBE_APPLYCONFIGURATION_GEN):
-	GOBIN=$(GOBIN_DIR) $(GO_INSTALL) k8s.io/code-generator/cmd/$(KUBE_APPLYCONFIGURATION_GEN_BIN) $(KUBE_APPLYCONFIGURATION_GEN_BIN) $(KUBE_APPLYCONFIGURATION_GEN_VER)
+.PHONY: build
+build: $(CMD)
 
+.PHONY: $(CMD)
+$(CMD): %: $(BUILD_DEST)/%
 
-.PHONY: build
-build: ## Build the project
-	mkdir -p bin
-	go build -o bin
+$(BUILD_DEST)/%: cmd/%
+	go build $(BUILDFLAGS) -o $@ ./cmd/$*
 
 .PHONY: install
 install:
 	go install
 
 .PHONY: codegen
-codegen: $(CONTROLLER_GEN) $(KUBE_CLIENT_GEN) $(KUBE_LISTER_GEN) $(KUBE_INFORMER_GEN) $(KUBE_APPLYCONFIGURATION_GEN) build
+codegen: build
 	./hack/update-codegen.sh
 	$(MAKE) imports
 
@@ -124,4 +100,5 @@ $(TOOLS_DIR)/verify_boilerplate.py:
 
 .PHONY: verify-boilerplate
 verify-boilerplate: $(TOOLS_DIR)/verify_boilerplate.py
-	$(TOOLS_DIR)/verify_boilerplate.py --boilerplate-dir=hack/boilerplate
+	$(TOOLS_DIR)/verify_boilerplate.py --boilerplate-dir=hack/boilerplate --skip examples
+	$(TOOLS_DIR)/verify_boilerplate.py --boilerplate-dir=hack/boilerplate/examples examples

README.md

@@ -1,43 +1,77 @@
-## Code Generators for KCP-aware informers and listers
+## Code Generators for KCP-aware clients, informers and listers
 
-### Usage:
+This repository contains code generation tools analogous to the Kubernetes
+code-generator. It contains:
 
-```
-code-generator <command> [input-flags]
-```
-
-where `<command>` can be one of:
-- lister
-- informer
+* `cluster-client-gen` to generate a cluster-aware clientset,
+* `cluster-informer-gen` to generate cluster-aware informers and
+* `cluster-lister-gen` to do the same for listers.
 
-It is possible to run the code generation for multiple components at once `code-generator lister,informer [input-flags]`
+Note that you need to have generated the versioned Kubernetes clientset and
+applyconfiguration packages already in order to generate and use cluster-aware
+code. Single-cluster listers and informers however are optional and the
+generator here can generate the necessary interfaces itself.
 
-#### Input flags:
+### Usage
 
-1. `--input-dir` - The directory path where APIs are defined. Make sure that the types are defined in `<inputDir>/pkg/apis/{$GROUP}/{$VERSION}`. For example, if your input apis are defined in `types.go` inside `examples/pkg/apis/apps/v1/types.go`, the input directory should be specified as `examples/pkg`. `{$GROUP}/{$VERSION}` is appended in the input path.
-**Note**: This is the relative path to the input directory where APIs live.
+It is strongly recommended to use the provided `cluster_codegen.sh`, which works
+very much like Kubernetes' `kube_codegen.sh`. A common way to acquire it is to
+have a synthetic Go dependency on `github.com/kcp-dev/code-generator/v3/cmd/cluster-client-gen`
+(often done in a `hack/tools.go`) and then call it like so in your project:
 
-2. `--output-dir` - The directory where output clients are to be generated. It defaults to the `output` folder under current working directory.
-    - Listers are output to `<outputDir>/listers/${GROUP}/${VERSION}/${TYPE}.go`
-    - Individual informers are output to `<outputDir>/informers/externalversions/${GROUP}/${VERSION}/${TYPE}.go`
+```bash
+# Often you would want to generate both the regular Kubernetes clientset and
+# the cluster-aware clienset.
 
-3. `--clientset-api-path` - The path to where `clientset` generated by `k8s.io/code-gen` is present.
+CODEGEN_PKG="$(go list -f '{{.Dir}}' -m k8s.io/code-generator)"
+CLUSTER_CODEGEN_PKG="$(go list -f '{{.Dir}}' -m github.com/kcp-dev/code-generator/v3)"
 
-4. `--group-versions` - List of group versions in the format `group:version`. Define multiple groups by specifying the flag again. For example, the inputs can be: 
-    - `--group-version="apps:v1"`
-    - `--group-versions="rbac:v1" --group-versions="apps:v1"`
-    - `--group-version="rbac:v1,v2"`
+source "$CODEGEN_PKG/kube_codegen.sh"
+source "$CLUSTER_CODEGEN_PKG/cluster_codegen.sh"
 
-5. `--go-header-file` - Path to the header file.
+# Now you can call kube::codegen:: and cluster::codegen:: functions.
 
-Example:
-To run it locally and see how it works, use the following command:
+kube::codegen::gen_client \
+  --boilerplate hack/boilerplate/examples/boilerplate.generatego.txt \
+  --output-dir pkg/generated \
+  --output-pkg acme.corp/pkg/generated \
+  --with-applyconfig \
+  --applyconfig-name applyconfigurations \
+  --with-watch \
+  ./pkg/apis
 
+cluster::codegen::gen_client \
+  --boilerplate hack/boilerplate/examples/boilerplate.generatego.txt \
+  --output-dir pkg/clients \
+  --output-pkg acme.corp/pkg/clients \
+  --with-watch \
+  --single-cluster-versioned-clientset-pkg acme.corp/pkg/generated/clientset/versioned \
+  --single-cluster-applyconfigurations-pkg acme.corp/pkg/generated/applyconfigurations \
+  --single-cluster-listers-pkg acme.corp/pkg/generated/listers \
+  --single-cluster-informers-pkg acme.corp/pkg/generated/informers/externalversions \
+  pkg/apis
 ```
-go run main.go informer,lister --go-header-file testdata/header.txt 
-                      --clientset-api-path=github.com/kcp-dev/code-generator/testdata/pkg/generated/clientset/versioned 
-                      --input-dir testdata/pkg/apis 
-                      --output-dir testdata/pkg --group-versions example:v1
-```
 
-creates output folders in `testdata/pkg/informers` and `testdata/pkg/listers`.
+Please refer to the [cluster_codegen.sh](./cluster_codegen.sh) for more information
+on the available command line flags.
+
+## Contributing
+
+We ❤️ our contributors! If you're interested in helping us out, please check out [contributing to kcp](https://docs.kcp.io/kcp/main/contributing/).
+
+This community has a [Code of Conduct](./code-of-conduct.md). Please make sure to follow it.
+
+## Getting in touch
+
+There are several ways to communicate with us:
+
+- The [`#kcp-dev` channel](https://app.slack.com/client/T09NY5SBT/C021U8WSAFK) in the [Kubernetes Slack workspace](https://slack.k8s.io).
+- Our mailing lists:
+    - [kcp-dev](https://groups.google.com/g/kcp-dev) for development discussions.
+    - [kcp-users](https://groups.google.com/g/kcp-users) for discussions among users and potential users.
+- By joining the kcp-dev mailing list, you should receive an invite to our bi-weekly community meetings.
+- See recordings of past community meetings on [YouTube](https://www.youtube.com/channel/UCfP_yS5uYix0ppSbm2ltS5Q).
+- The next community meeting dates are available via our [CNCF community group](https://community.cncf.io/kcp/).
+- Check the [community meeting notes document](https://docs.google.com/document/d/1PrEhbmq1WfxFv1fTikDBZzXEIJkUWVHdqDFxaY1Ply4) for future and past meeting agendas.
+- Browse the [shared Google Drive](https://drive.google.com/drive/folders/1FN7AZ_Q1CQor6eK0gpuKwdGFNwYI517M?usp=sharing) to share design docs, notes, etc.
+    - Members of the kcp-dev mailing list can view this drive.