add more logging into sidekick

main.go

@@ -21,6 +21,9 @@ import (
  "crypto/tls"
  "crypto/x509"
  "fmt"
+ "io"
+ "io/ioutil"
+ "log"
  "math/big"
  "math/rand"
  "net"
@@ -37,6 +40,8 @@ import (
  "github.com/minio/minio/pkg/ellipses"
 )
 
+const slashSeparator = "/"
+
 // Backend entity to which requests gets load balanced.
 type Backend struct {
  endpoint string
@@ -52,42 +57,47 @@ type Backend struct {
 func (b *Backend) ErrorHandler(w http.ResponseWriter, r *http.Request, err error) {
  if err != nil {
  if b.logging {
- fmt.Println(b.endpoint, err)
+ log.Printf("reverseProxy %s, error: %s\n", b.endpoint, err)
  }
  b.up = false
  }
 }
 
 // healthCheck - background routine which checks if a backend is up or down.
 func (b *Backend) healthCheck() {
- healthCheckURL := strings.TrimSuffix(b.endpoint, "/") + b.healthCheckPath
+ healthCheckURL := strings.TrimSuffix(b.endpoint, slashSeparator) + b.healthCheckPath
  for {
  req, err := http.NewRequest(http.MethodGet, healthCheckURL, nil)
  if err != nil {
  if b.logging {
- fmt.Printf("%s %s fails\n", b.endpoint, err)
+ log.Printf("%s is down, error: %s\n", b.endpoint, err)
  }
  b.up = false
  time.Sleep(time.Duration(b.healthCheckDuration) * time.Second)
  continue
  }
 
  resp, err := b.httpClient.Do(req)
- switch {
- case err == nil && b.healthCheckPath == "":
- resp.Body.Close()
- fallthrough
- case err == nil && resp.StatusCode == http.StatusOK:
- resp.Body.Close()
+ if err != nil {
+ b.httpClient.CloseIdleConnections()
+ b.up = false
  if b.logging {
- fmt.Printf("%s is up\n", b.endpoint)
+ // network error print it here
+ log.Printf("%s is down : err: %s\n", b.endpoint, err)
  }
- b.up = true
- default:
+ } else {
+ // Drain the connection.
+ io.Copy(ioutil.Discard, resp.Body)
+ resp.Body.Close()
+
+ b.up = resp.StatusCode == http.StatusOK
  if b.logging {
- fmt.Printf("%s is down : %s\n", b.endpoint, err)
+ if !b.up {
+ log.Printf("%s is down, http status: %s\n", b.endpoint, resp.Status)
+ } else {
+ log.Printf("%s is up, http status: %s\n", b.endpoint, resp.Status)
+ }
  }
- b.up = false
  }
  time.Sleep(time.Duration(b.healthCheckDuration) * time.Second)
  }
@@ -154,8 +164,8 @@ func (lb *loadBalancer) listProxy() *httputil.ReverseProxy {
 }
 
 func trimPrefixSuffixSlash(p string) string {
- p = strings.TrimPrefix(p, "/")
- p = strings.TrimSuffix(p, "/")
+ p = strings.TrimPrefix(p, slashSeparator)
+ p = strings.TrimSuffix(p, slashSeparator)
  return p
 }
 
@@ -166,7 +176,7 @@ func (lb *loadBalancer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
  var proxy *httputil.ReverseProxy
 
- if strings.Contains(p, "/") {
+ if strings.Contains(p, slashSeparator) {
  // Object calls get distributed across the backends.
  proxy = lb.nextProxy()
  } else {
@@ -273,8 +283,8 @@ func sidekickMain(ctx *cli.Context) {
  addr := ctx.GlobalString("address")
  logging := ctx.GlobalBool("logging")
 
- if !strings.HasPrefix(healthCheckPath, "/") {
- healthCheckPath = "/" + healthCheckPath
+ if !strings.HasPrefix(healthCheckPath, slashSeparator) {
+ healthCheckPath = slashSeparator + healthCheckPath
  }
 
  var endpoints []string
@@ -298,7 +308,7 @@ func sidekickMain(ctx *cli.Context) {
 
  var backends []*Backend
  for _, endpoint := range endpoints {
- endpoint = strings.TrimSuffix(endpoint, "/")
+ endpoint = strings.TrimSuffix(endpoint, slashSeparator)
  target, err := url.Parse(endpoint)
  if err != nil {
  console.Fatalln(fmt.Errorf("Unable to parse input arg %s: %s", endpoint, err))