Fix fetcher of newdeploy pod error out when starting up (#1210)

* Connect to k8s API server to ensure network connectivity
* Fix readiness probe path

pkg/error/network/error.go

@@ -0,0 +1,107 @@
+/*
+Copyright 2019 The Fission Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package network
+
+import (
+	"net"
+	"net/url"
+	"os"
+	"strings"
+	"syscall"
+)
+
+type (
+	Error struct {
+		err error
+	}
+)
+
+// Adapter returns an Error if the pass-in error is a network error;
+// otherwise, nil will be returned.
+func Adapter(err error) *Error {
+	if err == nil {
+		return nil
+	}
+
+	netErr, ok := err.(net.Error)
+	if !ok {
+		return nil
+	}
+
+	return &Error{err: netErr}
+}
+
+func (e Error) Error() string {
+	return e.err.Error()
+}
+
+// IsDialError returns true if its a network dial error
+func (e Error) IsDialError() bool {
+	netOpErr, ok := e.err.(*net.OpError)
+	if !ok {
+		return false
+	}
+
+	if netOpErr.Op == "dial" {
+		return true
+	}
+
+	return false
+}
+
+// IsConnRefusedError returns true if an error is a "connection refused" error
+func (e Error) IsConnRefusedError() bool {
+	urlErr, ok := e.err.(*url.Error)
+	if !ok {
+		return false
+	}
+
+	if strings.Contains(urlErr.Error(), "connection refused") {
+		return true
+	}
+
+	netOpErr, ok := e.err.(*net.OpError)
+	if !ok {
+		return false
+	}
+
+	switch t := netOpErr.Err.(type) {
+	case *os.SyscallError:
+		if errno, ok := t.Err.(syscall.Errno); ok {
+			switch errno {
+			case syscall.ECONNREFUSED:
+				return true
+			}
+		}
+	}
+
+	return false
+}
+
+// IsUnsupportedProtoScheme returns true if an error is a "unsupported protocol scheme" error
+func (e Error) IsUnsupportedProtoScheme() bool {
+	urlErr, ok := e.err.(*url.Error)
+	if !ok {
+		return false
+	}
+
+	if strings.Contains(urlErr.Error(), "unsupported protocol scheme") {
+		return true
+	}
+
+	return false
+}