istio.io/istio@v0.0.0-20240520182934-d79c90f27776/pilot/cmd/pilot-agent/app/wait.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 app
    16  
    17  import (
    18  	"fmt"
    19  	"io"
    20  	"net/http"
    21  	"time"
    22  
    23  	"github.com/spf13/cobra"
    24  
    25  	"istio.io/istio/pkg/log"
    26  )
    27  
    28  var (
    29  	timeoutSeconds       int
    30  	requestTimeoutMillis int
    31  	periodMillis         int
    32  	url                  string
    33  
    34  	waitCmd = &cobra.Command{
    35  		Use:   "wait",
    36  		Short: "Waits until the Envoy proxy is ready",
    37  		RunE: func(c *cobra.Command, args []string) error {
    38  			client := &http.Client{
    39  				Timeout: time.Duration(requestTimeoutMillis) * time.Millisecond,
    40  			}
    41  			log.Infof("Waiting for Envoy proxy to be ready (timeout: %d seconds)...", timeoutSeconds)
    42  
    43  			var err error
    44  			timeout := time.After(time.Duration(timeoutSeconds) * time.Second)
    45  
    46  			for {
    47  				select {
    48  				case <-timeout:
    49  					return fmt.Errorf("timeout waiting for Envoy proxy to become ready. Last error: %v", err)
    50  				case <-time.After(time.Duration(periodMillis) * time.Millisecond):
    51  					err = checkIfReady(client, url)
    52  					if err == nil {
    53  						log.Infof("Envoy is ready!")
    54  						return nil
    55  					}
    56  					log.Debugf("Not ready yet: %v", err)
    57  				}
    58  			}
    59  		},
    60  	}
    61  )
    62  
    63  func checkIfReady(client *http.Client, url string) error {
    64  	req, err := http.NewRequest(http.MethodGet, url, nil)
    65  	if err != nil {
    66  		return err
    67  	}
    68  	resp, err := client.Do(req)
    69  	if err != nil {
    70  		return err
    71  	}
    72  	defer resp.Body.Close()
    73  	_, err = io.ReadAll(resp.Body)
    74  	if err != nil {
    75  		return err
    76  	}
    77  	if resp.StatusCode != http.StatusOK {
    78  		return fmt.Errorf("HTTP status code %v", resp.StatusCode)
    79  	}
    80  	return nil
    81  }
    82  
    83  func init() {
    84  	waitCmd.PersistentFlags().IntVar(&timeoutSeconds, "timeoutSeconds", 60, "maximum number of seconds to wait for Envoy to be ready")
    85  	waitCmd.PersistentFlags().IntVar(&requestTimeoutMillis, "requestTimeoutMillis", 500, "number of milliseconds to wait for response")
    86  	waitCmd.PersistentFlags().IntVar(&periodMillis, "periodMillis", 500, "number of milliseconds to wait between attempts")
    87  	waitCmd.PersistentFlags().StringVar(&url, "url", "http://localhost:15021/healthz/ready", "URL to use in requests")
    88  }