Initial commit

vendor/sigs.k8s.io/controller-runtime/pkg/manager/internal.go

@@ -0,0 +1,291 @@
+/*
+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 manager
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/rest"
+	"k8s.io/client-go/tools/leaderelection"
+	"k8s.io/client-go/tools/leaderelection/resourcelock"
+	"k8s.io/client-go/tools/record"
+	"sigs.k8s.io/controller-runtime/pkg/cache"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/metrics"
+	"sigs.k8s.io/controller-runtime/pkg/recorder"
+	"sigs.k8s.io/controller-runtime/pkg/runtime/inject"
+	logf "sigs.k8s.io/controller-runtime/pkg/runtime/log"
+	"sigs.k8s.io/controller-runtime/pkg/webhook/admission/types"
+)
+
+var log = logf.KBLog.WithName("manager")
+
+type controllerManager struct {
+	// config is the rest.config used to talk to the apiserver.  Required.
+	config *rest.Config
+
+	// scheme is the scheme injected into Controllers, EventHandlers, Sources and Predicates.  Defaults
+	// to scheme.scheme.
+	scheme *runtime.Scheme
+	// admissionDecoder is used to decode an admission.Request.
+	admissionDecoder types.Decoder
+
+	// runnables is the set of Controllers that the controllerManager injects deps into and Starts.
+	runnables []Runnable
+
+	cache cache.Cache
+
+	// TODO(directxman12): Provide an escape hatch to get individual indexers
+	// client is the client injected into Controllers (and EventHandlers, Sources and Predicates).
+	client client.Client
+
+	// fieldIndexes knows how to add field indexes over the Cache used by this controller,
+	// which can later be consumed via field selectors from the injected client.
+	fieldIndexes client.FieldIndexer
+
+	// recorderProvider is used to generate event recorders that will be injected into Controllers
+	// (and EventHandlers, Sources and Predicates).
+	recorderProvider recorder.Provider
+
+	// resourceLock forms the basis for leader election
+	resourceLock resourcelock.Interface
+
+	// mapper is used to map resources to kind, and map kind and version.
+	mapper meta.RESTMapper
+
+	// metricsListener is used to serve prometheus metrics
+	metricsListener net.Listener
+
+	mu      sync.Mutex
+	started bool
+	errChan chan error
+
+	// internalStop is the stop channel *actually* used by everything involved
+	// with the manager as a stop channel, so that we can pass a stop channel
+	// to things that need it off the bat (like the Channel source).  It can
+	// be closed via `internalStopper` (by being the same underlying channel).
+	internalStop <-chan struct{}
+
+	// internalStopper is the write side of the internal stop channel, allowing us to close it.
+	// It and `internalStop` should point to the same channel.
+	internalStopper chan<- struct{}
+
+	startCache func(stop <-chan struct{}) error
+}
+
+// Add sets dependencies on i, and adds it to the list of runnables to start.
+func (cm *controllerManager) Add(r Runnable) error {
+	cm.mu.Lock()
+	defer cm.mu.Unlock()
+
+	// Set dependencies on the object
+	if err := cm.SetFields(r); err != nil {
+		return err
+	}
+
+	// Add the runnable to the list
+	cm.runnables = append(cm.runnables, r)
+	if cm.started {
+		// If already started, start the controller
+		go func() {
+			cm.errChan <- r.Start(cm.internalStop)
+		}()
+	}
+
+	return nil
+}
+
+func (cm *controllerManager) SetFields(i interface{}) error {
+	if _, err := inject.ConfigInto(cm.config, i); err != nil {
+		return err
+	}
+	if _, err := inject.ClientInto(cm.client, i); err != nil {
+		return err
+	}
+	if _, err := inject.SchemeInto(cm.scheme, i); err != nil {
+		return err
+	}
+	if _, err := inject.CacheInto(cm.cache, i); err != nil {
+		return err
+	}
+	if _, err := inject.InjectorInto(cm.SetFields, i); err != nil {
+		return err
+	}
+	if _, err := inject.StopChannelInto(cm.internalStop, i); err != nil {
+		return err
+	}
+	if _, err := inject.DecoderInto(cm.admissionDecoder, i); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (cm *controllerManager) GetConfig() *rest.Config {
+	return cm.config
+}
+
+func (cm *controllerManager) GetClient() client.Client {
+	return cm.client
+}
+
+func (cm *controllerManager) GetScheme() *runtime.Scheme {
+	return cm.scheme
+}
+
+func (cm *controllerManager) GetAdmissionDecoder() types.Decoder {
+	return cm.admissionDecoder
+}
+
+func (cm *controllerManager) GetFieldIndexer() client.FieldIndexer {
+	return cm.fieldIndexes
+}
+
+func (cm *controllerManager) GetCache() cache.Cache {
+	return cm.cache
+}
+
+func (cm *controllerManager) GetRecorder(name string) record.EventRecorder {
+	return cm.recorderProvider.GetEventRecorderFor(name)
+}
+
+func (cm *controllerManager) GetRESTMapper() meta.RESTMapper {
+	return cm.mapper
+}
+
+func (cm *controllerManager) serveMetrics(stop <-chan struct{}) {
+	handler := promhttp.HandlerFor(metrics.Registry, promhttp.HandlerOpts{
+		ErrorHandling: promhttp.HTTPErrorOnError,
+	})
+	// TODO(JoelSpeed): Use existing Kubernetes machinery for serving metrics
+	mux := http.NewServeMux()
+	mux.Handle("/metrics", handler)
+	server := http.Server{
+		Handler: mux,
+	}
+	// Run the server
+	go func() {
+		if err := server.Serve(cm.metricsListener); err != nil && err != http.ErrServerClosed {
+			cm.errChan <- err
+		}
+	}()
+
+	// Shutdown the server when stop is closed
+	select {
+	case <-stop:
+		if err := server.Shutdown(context.Background()); err != nil {
+			cm.errChan <- err
+		}
+	}
+}
+
+func (cm *controllerManager) Start(stop <-chan struct{}) error {
+	// join the passed-in stop channel as an upstream feeding into cm.internalStopper
+	defer close(cm.internalStopper)
+
+	// Metrics should be served whether the controller is leader or not.
+	// (If we don't serve metrics for non-leaders, prometheus will still scrape
+	// the pod but will get a connection refused)
+	if cm.metricsListener != nil {
+		go cm.serveMetrics(cm.internalStop)
+	}
+
+	if cm.resourceLock != nil {
+		err := cm.startLeaderElection()
+		if err != nil {
+			return err
+		}
+	} else {
+		go cm.start()
+	}
+
+	select {
+	case <-stop:
+		// We are done
+		return nil
+	case err := <-cm.errChan:
+		// Error starting a controller
+		return err
+	}
+}
+
+func (cm *controllerManager) start() {
+	cm.mu.Lock()
+	defer cm.mu.Unlock()
+
+	// Start the Cache. Allow the function to start the cache to be mocked out for testing
+	if cm.startCache == nil {
+		cm.startCache = cm.cache.Start
+	}
+	go func() {
+		if err := cm.startCache(cm.internalStop); err != nil {
+			cm.errChan <- err
+		}
+	}()
+
+	// Wait for the caches to sync.
+	// TODO(community): Check the return value and write a test
+	cm.cache.WaitForCacheSync(cm.internalStop)
+
+	// Start the runnables after the cache has synced
+	for _, c := range cm.runnables {
+		// Controllers block, but we want to return an error if any have an error starting.
+		// Write any Start errors to a channel so we can return them
+		ctrl := c
+		go func() {
+			cm.errChan <- ctrl.Start(cm.internalStop)
+		}()
+	}
+
+	cm.started = true
+}
+
+func (cm *controllerManager) startLeaderElection() (err error) {
+	l, err := leaderelection.NewLeaderElector(leaderelection.LeaderElectionConfig{
+		Lock: cm.resourceLock,
+		// Values taken from: https://github.com/kubernetes/apiserver/blob/master/pkg/apis/config/v1alpha1/defaults.go
+		// TODO(joelspeed): These timings should be configurable
+		LeaseDuration: 15 * time.Second,
+		RenewDeadline: 10 * time.Second,
+		RetryPeriod:   2 * time.Second,
+		Callbacks: leaderelection.LeaderCallbacks{
+			OnStartedLeading: func(_ context.Context) {
+				cm.start()
+			},
+			OnStoppedLeading: func() {
+				// Most implementations of leader election log.Fatal() here.
+				// Since Start is wrapped in log.Fatal when called, we can just return
+				// an error here which will cause the program to exit.
+				cm.errChan <- fmt.Errorf("leader election lost")
+			},
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	// Start the leader elector process
+	go l.Run(context.Background())
+	return nil
+}