[FAB-8548] Fix CA started with wrong cert path

Although CA cert file was specified in arguments and it was
the wrong path, key and certification files were generated
and fabric-ca-server starts successfully.
This patch informs the cert file path does not exist.

Change-Id: I1ea8aab95f61024233d904c695b8af19279c9860
Signed-off-by: Nao Nishijima <[email protected]>

lib/ca.go

@@ -249,6 +249,7 @@ func (ca *CA) initKeyMaterial(renew bool) error {
 			}
 			return nil
 		}
+		log.Warning(newServerError(ErrCACertFileNotFound, "The specified CA certificate file %s does not exist", certFile))
 	}
 
 	// Get the CA cert

lib/servererror.go

@@ -167,6 +167,8 @@ const (
 	ErrGettingCert = 67
 	// Error occurred parsing variable as an integer
 	ErrParsingIntEnvVar = 68
+	// CA certificate file is not found warning message
+	ErrCACertFileNotFound = 69
 )
 
 // Construct a new HTTP error.
@@ -243,19 +245,33 @@ func (he *httpErr) writeResponse(w http.ResponseWriter) error {
 	return nil
 }
 
-type fatalErr struct {
+type serverErr struct {
 	code int
 	msg  string
 }
 
-func newFatalError(code int, format string, args ...interface{}) *fatalErr {
+type fatalErr struct {
+	serverErr
+}
+
+func newServerError(code int, format string, args ...interface{}) *serverErr {
 	msg := fmt.Sprintf(format, args...)
-	return &fatalErr{
+	return &serverErr{
 		code: code,
 		msg:  msg,
 	}
 }
 
+func newFatalError(code int, format string, args ...interface{}) *fatalErr {
+	msg := fmt.Sprintf(format, args...)
+	return &fatalErr{
+		serverErr{
+			code: code,
+			msg:  msg,
+		},
+	}
+}
+
 func (fe *fatalErr) Error() string {
 	return fe.String()
 }