comments, variable names, errors

Author: dwhitena

execution.go

@@ -7,14 +7,16 @@ import (
 	repl "github.com/gopherds/gophernotes/replpkg"
 )
 
-// REPLSession manages the I/O to/from the notebook
-var REPLSession *repl.Session
-var fset *token.FileSet
+var (
+	// REPLSession manages the I/O to/from the notebook.
+	REPLSession *repl.Session
+	fset        *token.FileSet
+)
 
-// ExecCounter is incremented each time we run user code in the notebook
+// ExecCounter is incremented each time we run user code in the notebook.
 var ExecCounter int
 
-// SetupExecutionEnvironment initializes the REPL session and set of tmp files
+// SetupExecutionEnvironment initializes the REPL session and set of tmp files.
 func SetupExecutionEnvironment() {
 
 	var err error
@@ -33,7 +35,7 @@ type OutputMsg struct {
 	Metadata  map[string]interface{} `json:"metadata"`
 }
 
-// ErrMsg encodes the traceback of errors output to the notebook
+// ErrMsg encodes the traceback of errors output to the notebook.
 type ErrMsg struct {
 	EName     string   `json:"ename"`
 	EValue    string   `json:"evalue"`
@@ -54,7 +56,7 @@ func HandleExecuteRequest(receipt MsgReceipt) {
 	}
 	content["execution_count"] = ExecCounter
 
-	// the compilation/execution magic happen here
+	// Do the compilation/execution magic.
 	val, err, stderr := REPLSession.Eval(code)
 
 	if err == nil {

gophernotes.go

@@ -147,13 +147,12 @@ func HandleShutdownRequest(receipt MsgReceipt) {
 	os.Exit(0)
 }
 
-// RunKernel is the main entry point to start the kernel. This is what is called by the
-// gophernotes executable.
+// RunKernel is the main entry point to start the kernel.
 func RunKernel(connectionFile string, logwriter io.Writer) {
 
 	logger = log.New(logwriter, "gophernotes ", log.LstdFlags)
 
-	// set up the "Session" with the replpkg
+	// Set up the "Session" with the replpkg.
 	SetupExecutionEnvironment()
 
 	var connInfo ConnectionInfo
@@ -166,7 +165,7 @@ func RunKernel(connectionFile string, logwriter io.Writer) {
 	}
 	logger.Printf("%+v\n", connInfo)
 
-	// Set up the ZMQ sockets through which the kernel will communicate
+	// Set up the ZMQ sockets through which the kernel will communicate.
 	sockets, err := PrepareSockets(connInfo)
 	if err != nil {
 		log.Fatalln(err)
@@ -178,8 +177,8 @@ func RunKernel(connectionFile string, logwriter io.Writer) {
 		zmq.PollItem{Socket: sockets.ControlSocket, Events: zmq.POLLIN},
 	}
 
+	// Start a message receiving loop.
 	var msgparts [][]byte
-	// Message receiving loop:
 	for {
 		if _, err = zmq.Poll(pi, -1); err != nil {
 			log.Fatalln(err)
@@ -189,17 +188,21 @@ func RunKernel(connectionFile string, logwriter io.Writer) {
 			msgparts, _ = pi[0].Socket.RecvMultipart(0)
 			msg, ids, err := WireMsgToComposedMsg(msgparts, sockets.Key)
 			if err != nil {
-				fmt.Println(err)
+				log.Println(err)
 				return
 			}
 			HandleShellMsg(MsgReceipt{msg, ids, sockets})
 		case pi[1].REvents&zmq.POLLIN != 0: // stdin socket - not implemented.
 			pi[1].Socket.RecvMultipart(0)
 		case pi[2].REvents&zmq.POLLIN != 0: // control socket - treat like shell socket.
-			msgparts, _ = pi[2].Socket.RecvMultipart(0)
+			msgparts, err = pi[2].Socket.RecvMultipart(0)
+			if err != nil {
+				log.Println(err)
+				return
+			}
 			msg, ids, err := WireMsgToComposedMsg(msgparts, sockets.Key)
 			if err != nil {
-				fmt.Println(err)
+				log.Println(err)
 				return
 			}
 			HandleShellMsg(MsgReceipt{msg, ids, sockets})

messages.go

@@ -12,7 +12,7 @@ import (
 	"github.com/pkg/errors"
 )
 
-// MsgHeader encodes header info for ZMQ messages
+// MsgHeader encodes header info for ZMQ messages.
 type MsgHeader struct {
 	MsgID    string `json:"msg_id"`
 	Username string `json:"username"`
@@ -39,15 +39,16 @@ func (e *InvalidSignatureError) Error() string {
 // WireMsgToComposedMsg translates a multipart ZMQ messages received from a socket into
 // a ComposedMsg struct and a slice of return identities. This includes verifying the
 // message signature.
-func WireMsgToComposedMsg(msgparts [][]byte, signkey []byte) (msg ComposedMsg,
-	identities [][]byte, err error) {
+func WireMsgToComposedMsg(msgparts [][]byte, signkey []byte) (ComposedMsg, [][]byte, error) {
+
 	i := 0
 	for string(msgparts[i]) != "<IDS|MSG>" {
 		i++
 	}
-	identities = msgparts[:i]
+	identities := msgparts[:i]
 
 	// Validate signature
+	var msg ComposedMsg
 	if len(signkey) != 0 {
 		mac := hmac.New(sha256.New, signkey)
 		for _, msgpart := range msgparts[i+2 : i+6] {
@@ -63,7 +64,7 @@ func WireMsgToComposedMsg(msgparts [][]byte, signkey []byte) (msg ComposedMsg,
 	json.Unmarshal(msgparts[i+3], &msg.ParentHeader)
 	json.Unmarshal(msgparts[i+4], &msg.Metadata)
 	json.Unmarshal(msgparts[i+5], &msg.Content)
-	return
+	return msg, identities, nil
 }
 
 // ToWireMsg translates a ComposedMsg into a multipart ZMQ message ready to send, and
@@ -98,7 +99,7 @@ func (msg ComposedMsg) ToWireMsg(signkey []byte) ([][]byte, error) {
 	}
 	msgparts[4] = content
 
-	// Sign the message
+	// Sign the message.
 	if len(signkey) != 0 {
 		mac := hmac.New(sha256.New, signkey)
 		for _, msgpart := range msgparts[1:] {