use istio client-go library instead of knative (#1661)

use istio client-go library instead of knative
bump kubernetes dependency version
change code coverage to codecov

vendor/k8s.io/apiserver/pkg/server/healthz/doc.go

@@ -17,5 +17,5 @@ limitations under the License.
 // Package healthz implements basic http server health checking.
 // Usage:
 //   import "k8s.io/apiserver/pkg/server/healthz"
-//   healthz.DefaultHealthz()
+//   healthz.InstallHandler(mux)
 package healthz // import "k8s.io/apiserver/pkg/server/healthz"

vendor/k8s.io/apiserver/pkg/server/healthz/healthz.go

@@ -25,29 +25,20 @@ import (
 	"sync/atomic"
 	"time"
 
-	"k8s.io/klog"
-
 	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/apiserver/pkg/server/httplog"
+	"k8s.io/klog"
 )
 
-// HealthzChecker is a named healthz checker.
-type HealthzChecker interface {
+// HealthChecker is a named healthz checker.
+type HealthChecker interface {
 	Name() string
 	Check(req *http.Request) error
 }
 
-var defaultHealthz = sync.Once{}
-
-// DefaultHealthz installs the default healthz check to the http.DefaultServeMux.
-func DefaultHealthz(checks ...HealthzChecker) {
-	defaultHealthz.Do(func() {
-		InstallHandler(http.DefaultServeMux, checks...)
-	})
-}
-
 // PingHealthz returns true automatically when checked
-var PingHealthz HealthzChecker = ping{}
+var PingHealthz HealthChecker = ping{}
 
 // ping implements the simplest possible healthz checker.
 type ping struct{}
@@ -62,7 +53,7 @@ func (ping) Check(_ *http.Request) error {
 }
 
 // LogHealthz returns true if logging is not blocked
-var LogHealthz HealthzChecker = &log{}
+var LogHealthz HealthChecker = &log{}
 
 type log struct {
 	startOnce    sync.Once
@@ -90,7 +81,7 @@ func (l *log) Check(_ *http.Request) error {
 }
 
 // NamedCheck returns a healthz checker for the given name and function.
-func NamedCheck(name string, check func(r *http.Request) error) HealthzChecker {
+func NamedCheck(name string, check func(r *http.Request) error) HealthChecker {
 	return &healthzCheck{name, check}
 }
 
@@ -98,22 +89,38 @@ func NamedCheck(name string, check func(r *http.Request) error) HealthzChecker {
 // "/healthz" to mux. *All handlers* for mux must be specified in
 // exactly one call to InstallHandler. Calling InstallHandler more
 // than once for the same mux will result in a panic.
-func InstallHandler(mux mux, checks ...HealthzChecker) {
+func InstallHandler(mux mux, checks ...HealthChecker) {
 	InstallPathHandler(mux, "/healthz", checks...)
 }
 
+// InstallReadyzHandler registers handlers for health checking on the path
+// "/readyz" to mux. *All handlers* for mux must be specified in
+// exactly one call to InstallHandler. Calling InstallHandler more
+// than once for the same mux will result in a panic.
+func InstallReadyzHandler(mux mux, checks ...HealthChecker) {
+	InstallPathHandler(mux, "/readyz", checks...)
+}
+
+// InstallLivezHandler registers handlers for liveness checking on the path
+// "/livez" to mux. *All handlers* for mux must be specified in
+// exactly one call to InstallHandler. Calling InstallHandler more
+// than once for the same mux will result in a panic.
+func InstallLivezHandler(mux mux, checks ...HealthChecker) {
+	InstallPathHandler(mux, "/livez", checks...)
+}
+
 // InstallPathHandler registers handlers for health checking on
 // a specific path to mux. *All handlers* for the path must be
 // specified in exactly one call to InstallPathHandler. Calling
 // InstallPathHandler more than once for the same path and mux will
 // result in a panic.
-func InstallPathHandler(mux mux, path string, checks ...HealthzChecker) {
+func InstallPathHandler(mux mux, path string, checks ...HealthChecker) {
 	if len(checks) == 0 {
 		klog.V(5).Info("No default health checks specified. Installing the ping handler.")
-		checks = []HealthzChecker{PingHealthz}
+		checks = []HealthChecker{PingHealthz}
 	}
 
-	klog.V(5).Info("Installing healthz checkers:", formatQuoted(checkerNames(checks...)...))
+	klog.V(5).Infof("Installing health checkers for (%v): %v", path, formatQuoted(checkerNames(checks...)...))
 
 	mux.Handle(path, handleRootHealthz(checks...))
 	for _, check := range checks {
@@ -126,13 +133,13 @@ type mux interface {
 	Handle(pattern string, handler http.Handler)
 }
 
-// healthzCheck implements HealthzChecker on an arbitrary name and check function.
+// healthzCheck implements HealthChecker on an arbitrary name and check function.
 type healthzCheck struct {
 	name  string
 	check func(r *http.Request) error
 }
 
-var _ HealthzChecker = &healthzCheck{}
+var _ HealthChecker = &healthzCheck{}
 
 func (c *healthzCheck) Name() string {
 	return c.name
@@ -152,7 +159,7 @@ func getExcludedChecks(r *http.Request) sets.String {
 }
 
 // handleRootHealthz returns an http.HandlerFunc that serves the provided checks.
-func handleRootHealthz(checks ...HealthzChecker) http.HandlerFunc {
+func handleRootHealthz(checks ...HealthChecker) http.HandlerFunc {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		failed := false
 		excluded := getExcludedChecks(r)
@@ -167,7 +174,7 @@ func handleRootHealthz(checks ...HealthzChecker) http.HandlerFunc {
 			if err := check.Check(r); err != nil {
 				// don't include the error since this endpoint is public.  If someone wants more detail
 				// they should have explicit permission to the detailed checks.
-				klog.V(6).Infof("healthz check %v failed: %v", check.Name(), err)
+				klog.V(4).Infof("healthz check %v failed: %v", check.Name(), err)
 				fmt.Fprintf(&verboseOut, "[-]%v failed: reason withheld\n", check.Name())
 				failed = true
 			} else {
@@ -181,10 +188,13 @@ func handleRootHealthz(checks ...HealthzChecker) http.HandlerFunc {
 		}
 		// always be verbose on failure
 		if failed {
-			http.Error(w, fmt.Sprintf("%vhealthz check failed", verboseOut.String()), http.StatusInternalServerError)
+			klog.V(2).Infof("%vhealthz check failed", verboseOut.String())
+			http.Error(httplog.Unlogged(r, w), fmt.Sprintf("%vhealthz check failed", verboseOut.String()), http.StatusInternalServerError)
 			return
 		}
 
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+		w.Header().Set("X-Content-Type-Options", "nosniff")
 		if _, found := r.URL.Query()["verbose"]; !found {
 			fmt.Fprint(w, "ok")
 			return
@@ -208,7 +218,7 @@ func adaptCheckToHandler(c func(r *http.Request) error) http.HandlerFunc {
 }
 
 // checkerNames returns the names of the checks in the same order as passed in.
-func checkerNames(checks ...HealthzChecker) []string {
+func checkerNames(checks ...HealthChecker) []string {
 	// accumulate the names of checks for printing them out.
 	checkerNames := make([]string, 0, len(checks))
 	for _, check := range checks {