made connection error limit into a configuration

README.md

@@ -81,6 +81,7 @@ Configurations can be set via flags or environment variables. To view available
 | Allowed hostnames | `--allowed-hostnames` | `ALLOWED_HOSTNAMES` | `"localhost"` | Comma delimited list of hostnames that are allowed to connect to the websocket |
 | Arguments | `--arguments` | `ARGUMENTS` | `"-l"` | Comma delimited list of arguments that should be passed to the target binary |
 | Command | `--command` | `COMMAND` | `"/bin/bash"` | Absolute path to the binary to run |
+| Connection error limit | `--connection-error-limit` | `CONNECTION_ERROR_LIMIT` | `10` | Number of times a connection should be re-attempted by the server to the XTerm.js frontend before the connection is considered dead and shut down |
 | Maximum buffer size in bytes | `--max-buffer-size-bytes` | `MAX_BUFFER_SIZE_BYTES` | `512` | Maximum length of input from the browser terminal |
 | Log format | `--log-format` | `LOG_FORMAT` | `"text"` | Format with which to output logs, one of `"json"` or `"text"` |
 | Log level | `--log-level` | `LOG_LEVEL` | `"debug"` | Minimum level of logs to output, one of `"trace"`, `"debug"`, `"info"`, `"warn"`, `"error"` |

cmd/cloudshell/config.go

@@ -24,6 +24,11 @@ var conf = config.Map{
 		Usage:     "absolute path to command to run",
 		Shorthand: "t",
 	},
+	"connection-error-limit": &config.Int{
+		Default:   10,
+		Usage:     "number of times a connection should be re-attempted before it's considered dead",
+		Shorthand: "l",
+	},
 	"max-buffer-size-bytes": &config.Int{
 		Default:   512,
 		Usage:     "maximum length of input from terminal",

cmd/cloudshell/main.go

@@ -38,6 +38,7 @@ func runE(_ *cobra.Command, _ []string) error {
 
 	// debug stuff
 	command := conf.GetString("command")
+	connectionErrorLimit := conf.GetInt("connection-error-limit")
 	arguments := conf.GetStringSlice("arguments")
 	allowedHostnames := conf.GetStringSlice("allowed-hostnames")
 	maxBufferSizeBytes := conf.GetInt("max-buffer-size-bytes")
@@ -62,6 +63,7 @@ func runE(_ *cobra.Command, _ []string) error {
 	log.Infof("arguments             : ['%s']", strings.Join(arguments, "', '"))
 
 	log.Infof("allowed hosts         : ['%s']", strings.Join(allowedHostnames, "', '"))
+	log.Infof("connection error limit: %v", connectionErrorLimit)
 	log.Infof("max buffer size       : %v bytes", maxBufferSizeBytes)
 	log.Infof("server address        : '%s' ", serverAddress)
 	log.Infof("server port           : %v", serverPort)
@@ -76,9 +78,10 @@ func runE(_ *cobra.Command, _ []string) error {
 
 	// this is the endpoint for xterm.js to connect to
 	xtermjsHandlerOptions := xtermjs.HandlerOpts{
-		AllowedHostnames: allowedHostnames,
-		Arguments:        arguments,
-		Command:          command,
+		AllowedHostnames:     allowedHostnames,
+		Arguments:            arguments,
+		Command:              command,
+		ConnectionErrorLimit: connectionErrorLimit,
 		CreateLogger: func(connectionUUID string, r *http.Request) xtermjs.Logger {
 			createRequestLog(r, map[string]interface{}{"connection_uuid": connectionUUID}).Infof("created logger for connection '%s'", connectionUUID)
 			return createRequestLog(nil, map[string]interface{}{"connection_uuid": connectionUUID})

pkg/xtermjs/handler_websocket.go

@@ -16,9 +16,7 @@ import (
 	"github.com/gorilla/websocket"
 )
 
-// ConnectionErrorLimit defines the number of consecutive errors that can happen
-// before a connection is considered unusable
-const ConnectionErrorLimit = 10
+const DefaultConnectionErrorLimit = 10
 
 type HandlerOpts struct {
 	// AllowedHostnames is a list of strings which will be matched to the client
@@ -28,6 +26,9 @@ type HandlerOpts struct {
 	Arguments []string
 	// Command is the path to the binary we should create a TTY for
 	Command string
+	// ConnectionErrorLimit defines the number of consecutive errors that can happen
+	// before a connection is considered unusable
+	ConnectionErrorLimit int
 	// CreateLogger when specified should return a logger that the handler will use.
 	// The string argument being passed in will be a unique identifier for the
 	// current connection. When not specified, logs will be sent to stdout
@@ -37,6 +38,10 @@ type HandlerOpts struct {
 
 func GetHandler(opts HandlerOpts) func(http.ResponseWriter, *http.Request) {
 	return func(w http.ResponseWriter, r *http.Request) {
+		connectionErrorLimit := opts.ConnectionErrorLimit
+		if connectionErrorLimit < 0 {
+			connectionErrorLimit = DefaultConnectionErrorLimit
+		}
 		maxBufferSizeBytes := opts.MaxBufferSizeBytes
 
 		connectionUUID, err := uuid.NewUUID()
@@ -98,7 +103,7 @@ func GetHandler(opts HandlerOpts) func(http.ResponseWriter, *http.Request) {
 			errorCounter := 0
 			for {
 				// consider the connection closed/errored out
-				if errorCounter > ConnectionErrorLimit {
+				if errorCounter > connectionErrorLimit {
 					waiter.Done()
 					break
 				}