add feature: java agent injector

Makefile

@@ -98,7 +98,7 @@ adapter-deploy:
 
 # Generate code
 generate: controller-gen
-	$(CONTROLLER_GEN) object:headerFile="hack/boilerplate.go.txt" paths="./apis/..."
+	#$(CONTROLLER_GEN) object:headerFile="hack/boilerplate.go.txt" paths="./apis/..."
 	$(MAKE) format
 
 GO_LICENSER := $(GOBIN)/go-licenser

apis/operator/v1alpha1/javaagent_webhook.go

@@ -0,0 +1,80 @@
+// Licensed to Apache Software Foundation (ASF) under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Apache Software Foundation (ASF) licenses this file to you 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 v1alpha1
+
+import (
+	"context"
+	"net/http"
+
+	corev1 "k8s.io/api/core/v1"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	logf "sigs.k8s.io/controller-runtime/pkg/log"
+	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
+
+	"github.com/apache/skywalking-swck/pkg/operator/injector"
+)
+
+// log is for logging in this package.
+var javaagentlog = logf.Log.WithName("javaagent")
+
+// nolint: lll
+// +kubebuilder:webhook:path=/mutate-v1-pod,mutating=true,failurePolicy=fail,groups="",resources=pods,verbs=create;update,versions=v1,name=mpod.kb.io
+
+// Javaagent injects java agent into Pods
+type Javaagent struct {
+	Client  client.Client
+	decoder *admission.Decoder
+}
+
+// Handle will process every coming pod under the
+// specified namespace which labeled "swck-injection=enabled"
+func (r *Javaagent) Handle(ctx context.Context, req admission.Request) admission.Response {
+	pod := &corev1.Pod{}
+
+	err := r.decoder.Decode(req, pod)
+	if err != nil {
+		return admission.Errored(http.StatusBadRequest, err)
+	}
+
+	// set Annotations to avoid repeated judgments
+	if pod.Annotations == nil {
+		pod.Annotations = map[string]string{}
+	}
+	// initialize all annotation types that can be overridden
+	anno, err := injector.NewAnnotations()
+	if err != nil {
+		javaagentlog.Error(err, "get NewAnnotations error")
+	}
+	// initialize Annotations to store the overlaied value
+	ao := injector.NewAnnotationOverlay()
+	// initialize SidecarInjectField and get injected strategy from annotations
+	s := injector.NewSidecarInjectField()
+	// initialize InjectProcess as a call chain
+	ip := injector.NewInjectProcess(ctx, s, anno, ao, pod, req, javaagentlog, r.Client)
+	// do real injection
+	return ip.Run()
+}
+
+// Javaagent implements admission.DecoderInjector.
+// A decoder will be automatically injected.
+
+// InjectDecoder injects the decoder.
+func (r *Javaagent) InjectDecoder(d *admission.Decoder) error {
+	r.decoder = d
+	return nil
+}

cmd/manager/manager.go

@@ -23,9 +23,9 @@ import (
 
 	"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/log/zap"
+	"sigs.k8s.io/controller-runtime/pkg/webhook"
 
 	operatorv1alpha1 "github.com/apache/skywalking-swck/apis/operator/v1alpha1"
 	operatorcontroller "github.com/apache/skywalking-swck/controllers/operator"
@@ -103,6 +103,16 @@ func main() {
 		setupLog.Error(err, "unable to create controller", "controller", "Fetcher")
 		os.Exit(1)
 	}
+
+	if err = (&operatorcontroller.ConfigMapReconciler{
+		Client:   mgr.GetClient(),
+		Log:      ctrl.Log.WithName("controllers").WithName("ConfigMap"),
+		Scheme:   mgr.GetScheme(),
+		FileRepo: repo.NewRepo("injector"),
+	}).SetupWithManager(mgr); err != nil {
+		setupLog.Error(err, "unable to create controller", "controller", "ConfigMap")
+		os.Exit(1)
+	}
 	if os.Getenv("ENABLE_WEBHOOKS") != "false" {
 		if err = (&operatorv1alpha1.OAPServer{}).SetupWebhookWithManager(mgr); err != nil {
 			setupLog.Error(err, "unable to create webhook", "webhook", "OAPServer")
@@ -116,6 +126,12 @@ func main() {
 			setupLog.Error(err, "unable to create webhook", "webhook", "Fetcher")
 			os.Exit(1)
 		}
+		// register a webhook to enable the agent injector，
+		setupLog.Info("registering /mutate-v1-pod webhook")
+		mgr.GetWebhookServer().Register("/mutate-v1-pod",
+			&webhook.Admission{
+				Handler: &operatorv1alpha1.Javaagent{Client: mgr.GetClient()}})
+		setupLog.Info("/mutate-v1-pod webhook is registered")
 	}
 	// +kubebuilder:scaffold:builder