server: More concise error messages.

On the CNI request failure, multus-cni prints out cmdArgs.  In all
cases, except for debug printing, this is done with %s and a special
printing function.  However, the handleCNIRequest is an exception for
some reason.  That leads to unintelligible error messages in case
of CNI request failures (severely abridged):

 CmdAdd (shim): CNI request failed with status 400:
 '&{ContainerID:<id> Netns:/var/run/netns/<uuid> IfName:eth0
    Args:<args> Path: StdinData:[125 121 111 117 114 32 97 100 118
    101 114 116 105 115 101 109 101 110 116 32 99 111 117 108 100
    32 98 101 32 104 101 114 101 125 ... another 650 numbers ]}
 ContainerID:"<id>" Netns:"/var/run/netns/<uuid>" IfName:"eth0"
 Args:"<args>" Path:"" ERRORED: error configuring pod ...

printCmdArgs() should be used for this case as well to avoid huge
hardly readable logs.

At the same time, the content of cniCmdArgs is always appended to
the error twice as seen in the example above.  The first time by the
HandleCNIRequest and another time by the handleCNIRequest.  Same for
the HandleDelegateRequest path.

Just removing the prefixing from the lower level handlers while
keeping higher level ones.  The 'ERRORED' part migrated to the higher
level handler functions to preserve the overall look of the error.

Signed-off-by: Ilya Maximets <[email protected]>

pkg/server/server.go

@@ -99,11 +99,7 @@ func (s *Server) HandleCNIRequest(cmd string, k8sArgs *types.K8sArgs, cniCmdArgs
 		return []byte(""), fmt.Errorf("unknown cmd type: %s", cmd)
 	}
 	logging.Verbosef("%s finished CNI request %s, result: %q, err: %v", cmd, printCmdArgs(cniCmdArgs), string(result), err)
-	if err != nil {
-		// Prefix errors with request info for easier failure debugging
-		return nil, fmt.Errorf("%s ERRORED: %v", printCmdArgs(cniCmdArgs), err)
-	}
-	return result, nil
+	return result, err
 }
 
 // HandleDelegateRequest is the CNI server handler function; it is invoked whenever
@@ -129,11 +125,7 @@ func (s *Server) HandleDelegateRequest(cmd string, k8sArgs *types.K8sArgs, cniCm
 		return []byte(""), fmt.Errorf("unknown cmd type: %s", cmd)
 	}
 	logging.Verbosef("%s finished Delegate request %s, result: %q, err: %v", cmd, printCmdArgs(cniCmdArgs), string(result), err)
-	if err != nil {
-		// Prefix errors with request info for easier failure debugging
-		return nil, fmt.Errorf("%s ERRORED: %v", printCmdArgs(cniCmdArgs), err)
-	}
-	return result, nil
+	return result, err
 }
 
 // GetListener creates a listener to a unix socket located in `socketPath`
@@ -415,7 +407,7 @@ func (s *Server) handleCNIRequest(r *http.Request) ([]byte, error) {
 	result, err := s.HandleCNIRequest(cmdType, k8sArgs, cniCmdArgs)
 	if err != nil {
 		// Prefix error with request information for easier debugging
-		return nil, fmt.Errorf("%+v %v", cniCmdArgs, err)
+		return nil, fmt.Errorf("%s ERRORED: %v", printCmdArgs(cniCmdArgs), err)
 	}
 	return result, nil
 }
@@ -442,7 +434,7 @@ func (s *Server) handleDelegateRequest(r *http.Request) ([]byte, error) {
 	result, err := s.HandleDelegateRequest(cmdType, k8sArgs, cniCmdArgs, cr.InterfaceAttributes)
 	if err != nil {
 		// Prefix error with request information for easier debugging
-		return nil, fmt.Errorf("%s %v", printCmdArgs(cniCmdArgs), err)
+		return nil, fmt.Errorf("%s ERRORED: %v", printCmdArgs(cniCmdArgs), err)
 	}
 	return result, nil
 }