istio.io/istio@v0.0.0-20240520182934-d79c90f27776/cni/pkg/nodeagent/healthServer.go (about)

     1  // Copyright Istio Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package nodeagent
    16  
    17  import (
    18  	"net/http"
    19  	"sync/atomic"
    20  
    21  	"istio.io/istio/cni/pkg/constants"
    22  )
    23  
    24  // StartHealthServer initializes and starts a web server that exposes liveness and readiness endpoints at port 8000.
    25  func StartHealthServer() (installReady *atomic.Value, watchReady *atomic.Value) {
    26  	router := http.NewServeMux()
    27  	installReady, watchReady = initRouter(router)
    28  
    29  	go func() {
    30  		_ = http.ListenAndServe(":"+constants.ReadinessPort, router)
    31  	}()
    32  
    33  	return
    34  }
    35  
    36  func initRouter(router *http.ServeMux) (installReady *atomic.Value, watchReady *atomic.Value) {
    37  	installReady = &atomic.Value{}
    38  	watchReady = &atomic.Value{}
    39  	installReady.Store(false)
    40  	watchReady.Store(false)
    41  
    42  	router.HandleFunc(constants.LivenessEndpoint, healthz)
    43  	router.HandleFunc(constants.ReadinessEndpoint, readyz(installReady, watchReady))
    44  
    45  	return
    46  }
    47  
    48  func healthz(w http.ResponseWriter, _ *http.Request) {
    49  	w.WriteHeader(http.StatusOK)
    50  }
    51  
    52  func readyz(installReady, watchReady *atomic.Value) http.HandlerFunc {
    53  	return func(w http.ResponseWriter, _ *http.Request) {
    54  		if !installReady.Load().(bool) || !watchReady.Load().(bool) {
    55  			http.Error(w, http.StatusText(http.StatusServiceUnavailable), http.StatusServiceUnavailable)
    56  			return
    57  		}
    58  		w.WriteHeader(http.StatusOK)
    59  	}
    60  }