adding ComponentConfig type and Options parsing

Signed-off-by: Chris Hein <me@chrishein.com>

Author: christopherhein

.golangci.yml

@@ -28,7 +28,6 @@ linters:
   - unparam
   - ineffassign
   - nakedret
-  - interfacer
   - gocyclo
   - lll
   - dupl

Makefile

@@ -39,6 +39,7 @@ TOOLS_DIR := hack/tools
 TOOLS_BIN_DIR := $(TOOLS_DIR)/bin
 GOLANGCI_LINT := $(abspath $(TOOLS_BIN_DIR)/golangci-lint)
 GO_APIDIFF := $(TOOLS_BIN_DIR)/go-apidiff
+CONTROLLER_GEN := $(TOOLS_BIN_DIR)/controller-gen
 
 # The help will print out all targets with their descriptions organized bellow their categories. The categories are represented by `##@` and the target descriptions by `##`.
 # The awk commands is responsible to read the entire set of makefiles included in this invocation, looking for lines of the file as xyz: ## something, and then pretty-format the target and help. Then, if there's a line with ##@ something, that gets pretty-printed as a category.
@@ -66,6 +67,9 @@ $(GOLANGCI_LINT): $(TOOLS_DIR)/go.mod # Build golangci-lint from tools folder.
 $(GO_APIDIFF): $(TOOLS_DIR)/go.mod # Build go-apidiff from tools folder.
 	cd $(TOOLS_DIR) && go build -tags=tools -o bin/go-apidiff github.com/joelanford/go-apidiff
 
+$(CONTROLLER_GEN): $(TOOLS_DIR)/go.mod # Build controller-gen from tools folder.
+	cd $(TOOLS_DIR) && go build -tags=tools -o bin/controller-gen sigs.k8s.io/controller-tools/cmd/controller-gen
+
 ## --------------------------------------
 ## Linting
 ## --------------------------------------
@@ -83,6 +87,10 @@ modules: ## Runs go mod to ensure modules are up to date.
 	go mod tidy
 	cd $(TOOLS_DIR); go mod tidy
 
+.PHONY: generate
+generate: $(CONTROLLER_GEN) ## Runs controller-gen for internal types for config file
+	$(CONTROLLER_GEN) object paths="./pkg/config/v1alpha1/...;./examples/configfile/custom/v1alpha1/..."
+
 ## --------------------------------------
 ## Cleanup / Verification
 ## --------------------------------------

designs/component-config.md

@@ -53,7 +53,7 @@ This change is important because:
 
 - Provide an interface for pulling configuration data out of exposed `ComponentConfig` types (see below for implementation)
 - Provide a new `ctrl.NewFromComponentConfig()` function for initializing a manager
-- Provide an embeddable `ControllerConfiguration` type for easily authoring `ComponentConfig` types
+- Provide an embeddable `ControllerManagerConfiguration` type for easily authoring `ComponentConfig` types
 - Provide an `DefaultControllerConfig` to make the switching easier for clients
 
 ### Non-Goals/Future Work
@@ -137,8 +137,8 @@ import (
 	configv1alpha1 "k8s.io/component-base/config/v1alpha1"
 )
 
-// ControllerConfiguration defines the embedded RuntimeConfiguration for controller-runtime clients.
-type ControllerConfiguration struct {
+// ControllerManagerConfiguration defines the embedded RuntimeConfiguration for controller-runtime clients.
+type ControllerManagerConfiguration struct {
 	Namespace string `json:"namespace,omitempty"` 
 
 	SyncPeriod *time.Duration `json:"syncPeriod,omitempty"`
@@ -147,16 +147,16 @@ type ControllerConfiguration struct {
 
 	MetricsBindAddress string `json:"metricsBindAddress,omitempty"`
 
-	Health ControllerConfigurationHealth `json:"health,omitempty"`
+	Health ControllerManagerConfigurationHealth `json:"health,omitempty"`
 
 	Port *int   `json:"port,omitempty"`
 	Host string `json:"host,omitempty"`
 
 	CertDir string `json:"certDir,omitempty"`
 }
 
-// ControllerConfigurationHealth defines the health configs
-type ControllerConfigurationHealth struct {
+// ControllerManagerConfigurationHealth defines the health configs
+type ControllerManagerConfigurationHealth struct {
 	HealthProbeBindAddress string `json:"healthProbeBindAddress,omitempty"`
 
 	ReadinessEndpointName string `json:"readinessEndpointName,omitempty"`
@@ -181,11 +181,11 @@ import (
 	configv1alpha1 "sigs.k8s.io/controller-runtime/pkg/apis/config/v1alpha1"
 )
 
-// DefaultControllerConfiguration is the Schema for the DefaultControllerConfigurations API
-type DefaultControllerConfiguration struct {
+// DefaultControllerManagerConfiguration is the Schema for the DefaultControllerManagerConfigurations API
+type DefaultControllerManagerConfiguration struct {
 	metav1.TypeMeta `json:",inline"`
 
-	Spec   configv1alpha1.ControllerConfiguration   `json:"spec,omitempty"`
+	Spec   configv1alpha1.ControllerManagerConfiguration   `json:"spec,omitempty"`
 }
 ```
 
@@ -194,19 +194,19 @@ This would allow a controller author to use this struct with any config that sup
 ```yaml
 # config.yaml
 apiVersion: config.somedomain.io/v1alpha1
-kind: FoobarControllerConfiguration
+kind: FoobarControllerManagerConfiguration
 spec:
   port: 9443
   metricsBindAddress: ":8080"
   leaderElection:
     leaderElect: false
 ```
 
-Given the following config and `DefaultControllerConfiguration` we'd be able to initialize the controller using the following.
+Given the following config and `DefaultControllerManagerConfiguration` we'd be able to initialize the controller using the following.
 
 
 ```golang
-mgr, err := ctrl.NewManagerFromComponentConfig(ctrl.GetConfigOrDie(), scheme, configname, &defaultv1alpha1.DefaultControllerConfiguration{})
+mgr, err := ctrl.NewManagerFromComponentConfig(ctrl.GetConfigOrDie(), scheme, configname, &defaultv1alpha1.DefaultControllerManagerConfiguration{})
 if err != nil {
 	// ...
 }
@@ -222,8 +222,8 @@ Since this design still requires setting up the initial `ComponentConfig` type a
 ```golang
 leaderElect := true
 
-config := &defaultv1alpha1.DefaultControllerConfiguration{
-	Spec: configv1alpha1.ControllerConfiguration{
+config := &defaultv1alpha1.DefaultControllerManagerConfiguration{
+	Spec: configv1alpha1.ControllerManagerConfiguration{
 		LeaderElection: configv1alpha1.LeaderElectionConfiguration{
 			LeaderElect: &leaderElect,
 		},
@@ -250,7 +250,7 @@ import (
 ) 
 
 type ControllerNameConfigurationSpec struct {
-	configv1alpha1.ControllerConfiguration `json:",inline"`
+	configv1alpha1.ControllerManagerConfiguration `json:",inline"`
 }
 
 type ControllerNameConfiguration struct {
@@ -260,20 +260,20 @@ type ControllerNameConfiguration struct {
 }
 ```
 
-Usage of this custom `ComponentConfig` type would require then changing the `ctrl.NewFromComponentConfig()` to use the new struct vs the `DefaultControllerConfiguration`.
+Usage of this custom `ComponentConfig` type would require then changing the `ctrl.NewFromComponentConfig()` to use the new struct vs the `DefaultControllerManagerConfiguration`.
 
 ## User Stories
 
 ### Controller Author with `controller-runtime` and default type
 
 - Mount `ConfigMap`
-- Initialize `ctrl.Manager` with `NewFromComponentConfig` with config name and `DefaultControllerConfiguration` type
+- Initialize `ctrl.Manager` with `NewFromComponentConfig` with config name and `DefaultControllerManagerConfiguration` type
 - Build custom controller as usual
 
 ### Controller Author with `controller-runtime` and custom type
 
 - Implement `ComponentConfig` type
-- Embed `ControllerConfiguration` type
+- Embed `ControllerManagerConfiguration` type
 - Mount `ConfigMap`
 - Initialize `ctrl.Manager` with `NewFromComponentConfig` with config name and `ComponentConfig` type
 - Build custom controller as usual
@@ -311,9 +311,9 @@ _Provided that the controller provides manifests_
 
 - [x] 02/19/2020: Proposed idea in an issue or [community meeting]
 - [x] 02/24/2020: Proposal submitted to `controller-runtime`
-- [x] 03/02/2020: Updated with default `DefaultControllerConfiguration`
+- [x] 03/02/2020: Updated with default `DefaultControllerManagerConfiguration`
 - [x] 03/04/2020: Updated with embeddable `RuntimeConfig`
-- [x] 03/10/2020: Updated embeddable name to `ControllerConfiguration`
+- [x] 03/10/2020: Updated embeddable name to `ControllerManagerConfiguration`
 
 
 <!-- Links -->

examples/configfile/builtin/config.yaml

@@ -0,0 +1,7 @@
+apiVersion: controller-runtime.sigs.k8s.io/v1alpha1
+kind: ControllerManagerConfiguration
+cacheNamespace: default
+metrics:
+  bindAddress: :9091
+leaderElection:
+  leaderElect: false

examples/configfile/builtin/controller.go

@@ -0,0 +1,74 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+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.
+*/
+
+package main
+
+import (
+	"context"
+	"fmt"
+
+	appsv1 "k8s.io/api/apps/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/controller-runtime/pkg/reconcile"
+)
+
+// reconcileReplicaSet reconciles ReplicaSets
+type reconcileReplicaSet struct {
+	// client can be used to retrieve objects from the APIServer.
+	client client.Client
+}
+
+// Implement reconcile.Reconciler so the controller can reconcile objects
+var _ reconcile.Reconciler = &reconcileReplicaSet{}
+
+func (r *reconcileReplicaSet) Reconcile(ctx context.Context, request reconcile.Request) (reconcile.Result, error) {
+	// set up a convenient log object so we don't have to type request over and over again
+	log := log.FromContext(ctx)
+
+	// Fetch the ReplicaSet from the cache
+	rs := &appsv1.ReplicaSet{}
+	err := r.client.Get(context.TODO(), request.NamespacedName, rs)
+	if errors.IsNotFound(err) {
+		log.Error(nil, "Could not find ReplicaSet")
+		return reconcile.Result{}, nil
+	}
+
+	if err != nil {
+		return reconcile.Result{}, fmt.Errorf("could not fetch ReplicaSet: %+v", err)
+	}
+
+	// Print the ReplicaSet
+	log.Info("Reconciling ReplicaSet", "container name", rs.Spec.Template.Spec.Containers[0].Name)
+
+	// Set the label if it is missing
+	if rs.Labels == nil {
+		rs.Labels = map[string]string{}
+	}
+	if rs.Labels["hello"] == "world" {
+		return reconcile.Result{}, nil
+	}
+
+	// Update the ReplicaSet
+	rs.Labels["hello"] = "world"
+	err = r.client.Update(context.TODO(), rs)
+	if err != nil {
+		return reconcile.Result{}, fmt.Errorf("could not write ReplicaSet: %+v", err)
+	}
+
+	return reconcile.Result{}, nil
+}

examples/configfile/builtin/main.go

@@ -0,0 +1,72 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+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.
+*/
+
+package main
+
+import (
+	"os"
+
+	appsv1 "k8s.io/api/apps/v1"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
+	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client/config"
+	cfg "sigs.k8s.io/controller-runtime/pkg/config"
+	"sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/controller-runtime/pkg/log/zap"
+	"sigs.k8s.io/controller-runtime/pkg/manager/signals"
+)
+
+var scheme = runtime.NewScheme()
+
+func init() {
+	log.SetLogger(zap.New())
+	clientgoscheme.AddToScheme(scheme)
+}
+
+func main() {
+	entryLog := log.Log.WithName("entrypoint")
+
+	// Setup a Manager
+	entryLog.Info("setting up manager")
+	mgr, err := ctrl.NewManager(config.GetConfigOrDie(), ctrl.Options{
+		Scheme: scheme,
+	}.AndFromOrDie(cfg.File()))
+	if err != nil {
+		entryLog.Error(err, "unable to set up overall controller manager")
+		os.Exit(1)
+	}
+
+	// Setup a new controller to reconcile ReplicaSets
+	err = ctrl.NewControllerManagedBy(mgr).
+		For(&appsv1.ReplicaSet{}).
+		Owns(&corev1.Pod{}).
+		Complete(&reconcileReplicaSet{
+			client: mgr.GetClient(),
+		})
+	if err != nil {
+		entryLog.Error(err, "unable to create controller")
+		os.Exit(1)
+	}
+
+	entryLog.Info("starting manager")
+	if err := mgr.Start(signals.SetupSignalHandler()); err != nil {
+		entryLog.Error(err, "unable to run manager")
+		os.Exit(1)
+	}
+}

examples/configfile/custom/config.yaml

@@ -0,0 +1,8 @@
+apiVersion: examples.x-k8s.io/v1alpha1
+kind: CustomControllerManagerConfiguration
+clusterName: example-test
+cacheNamespace: default
+metrics:
+  bindAddress: :8081
+leaderElection:
+  leaderElect: false