mirror of https://github.com/knative/pkg.git
110 lines
3.3 KiB
Go
110 lines
3.3 KiB
Go
/*
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Copyright 2023 The Knative Authors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package injection
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import (
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"context"
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"errors"
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"net/http"
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"strconv"
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"time"
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"knative.dev/pkg/logging"
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)
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// HealthCheckDefaultPort defines the default port number for health probes
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const HealthCheckDefaultPort = 8080
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// ServeHealthProbes sets up liveness and readiness probes.
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// If user sets no probes explicitly via the context then defaults are added.
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func ServeHealthProbes(ctx context.Context, port int) error {
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logger := logging.FromContext(ctx)
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server := http.Server{ReadHeaderTimeout: time.Minute, Handler: muxWithHandles(ctx), Addr: ":" + strconv.Itoa(port)}
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go func() {
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<-ctx.Done()
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_ = server.Shutdown(ctx)
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}()
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// start the web server on port and accept requests
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logger.Infof("Probes server listening on port %d", port)
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if err := server.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
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return err
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}
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return nil
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}
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func muxWithHandles(ctx context.Context) *http.ServeMux {
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mux := http.NewServeMux()
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readiness := getReadinessHandleOrDefault(ctx)
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liveness := getLivenessHandleOrDefault(ctx)
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mux.HandleFunc("/readiness", *readiness)
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mux.HandleFunc("/health", *liveness)
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return mux
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}
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func newDefaultProbesHandle(sigCtx context.Context) http.HandlerFunc {
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logger := logging.FromContext(sigCtx)
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return func(w http.ResponseWriter, r *http.Request) {
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f := func() error {
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select {
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// When we get SIGTERM (sigCtx done), let readiness probes start failing.
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case <-sigCtx.Done():
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logger.Info("Signal context canceled")
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return errors.New("received SIGTERM from kubelet")
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default:
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return nil
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}
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}
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if err := f(); err != nil {
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logger.Errorf("Healthcheck failed: %v", err)
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http.Error(w, err.Error(), http.StatusInternalServerError)
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} else {
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w.WriteHeader(http.StatusOK)
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}
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}
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}
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type addReadinessKey struct{}
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// AddReadiness signals to probe setup logic to add a user provided probe handler
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func AddReadiness(ctx context.Context, handlerFunc http.HandlerFunc) context.Context {
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return context.WithValue(ctx, addReadinessKey{}, &handlerFunc)
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}
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func getReadinessHandleOrDefault(ctx context.Context) *http.HandlerFunc {
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if ctx.Value(addReadinessKey{}) != nil {
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return ctx.Value(addReadinessKey{}).(*http.HandlerFunc)
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}
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defaultHandle := newDefaultProbesHandle(ctx)
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return &defaultHandle
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}
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type addLivenessKey struct{}
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// AddLiveness signals to probe setup logic to add a user provided probe handler
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func AddLiveness(ctx context.Context, handlerFunc http.HandlerFunc) context.Context {
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return context.WithValue(ctx, addLivenessKey{}, &handlerFunc)
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}
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func getLivenessHandleOrDefault(ctx context.Context) *http.HandlerFunc {
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if ctx.Value(addLivenessKey{}) != nil {
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return ctx.Value(addLivenessKey{}).(*http.HandlerFunc)
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}
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defaultHandle := newDefaultProbesHandle(ctx)
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return &defaultHandle
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}
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