Refactor main to decouple logic from actual main()

main.go

@@ -30,7 +30,27 @@ func main() {
 	flag.Parse()
 	undo = *undoF
 
-	if *debug {
+	setupLogging(*debug)
+
+	instructions := make(chan *LinkInstruction, 1000)
+	status := make(chan error)
+
+	startInputSource(*recurse, *file, instructions, status)
+
+	go handleStatusErrors(status)
+
+	instructionsDone := processInstructions(instructions)
+
+	if instructionsDone == 0 {
+		LogInfo("No instructions were processed")
+		os.Exit(1)
+	}
+	LogInfo("All done")
+}
+
+// setupLogging configures logging based on debug flag
+func setupLogging(debug bool) {
+	if debug {
 		log.SetFlags(log.Lmicroseconds | log.Lshortfile)
 		logFile, err := os.Create(programName + ".log")
 		if err != nil {
@@ -42,19 +62,19 @@ func main() {
 	} else {
 		log.SetFlags(log.Lmicroseconds)
 	}
+}
 
-	instructions := make(chan *LinkInstruction, 1000)
+// startInputSource determines and starts the appropriate input source
-	status := make(chan error)
+func startInputSource(recurse, file string, instructions chan *LinkInstruction, status chan error) {
-
 	// Check input sources in priority order
 	switch {
-	case *recurse != "":
+	case recurse != "":
-		LogInfo("Recurse: %s", *recurse)
+		LogInfo("Recurse: %s", recurse)
-		go ReadFromFilesRecursively(*recurse, instructions, status)
+		go ReadFromFilesRecursively(recurse, instructions, status)
 
-	case *file != "":
+	case file != "":
-		LogInfo("File: %s", *file)
+		LogInfo("File: %s", file)
-		go ReadFromFile(*file, instructions, status, true)
+		go ReadFromFile(file, instructions, status, true)
 
 	case len(flag.Args()) > 0:
 		LogInfo("Reading from command line arguments")
@@ -65,6 +85,12 @@ func main() {
 	// 	go ReadFromStdin(instructions, status)
 
 	default:
+		startDefaultInputSource(instructions, status)
+	}
+}
+
+// startDefaultInputSource tries to find default sync files
+func startDefaultInputSource(instructions chan *LinkInstruction, status chan error) {
 	if _, err := os.Stat("sync"); err == nil {
 		LogInfo("Using default sync file")
 		go ReadFromFile("sync", instructions, status, true)
@@ -75,6 +101,12 @@ func main() {
 		LogInfo("Using default sync.yml file")
 		go ReadFromFile("sync.yml", instructions, status, true)
 	} else {
+		showUsageAndExit()
+	}
+}
+
+// showUsageAndExit displays usage information and exits
+func showUsageAndExit() {
 	LogInfo("No input provided")
 	LogInfo("Provide input as: ")
 	LogInfo("Arguments - %s <source>,<target>,<force?>", programName)
@@ -83,10 +115,10 @@ func main() {
 	LogInfo("Folder (finding sync files in folder recursively) - %s -r <folder>", programName)
 	LogInfo("stdin - (cat <file> | %s)", programName)
 	os.Exit(1)
-		}
+}
-	}
 
-	go func() {
+// handleStatusErrors processes status channel errors
+func handleStatusErrors(status chan error) {
 	for {
 		err, ok := <-status
 		if !ok {
@@ -96,8 +128,10 @@ func main() {
 			LogError("%v", err)
 		}
 	}
-	}()
+}
 
+// processInstructions processes all instructions from the channel
+func processInstructions(instructions chan *LinkInstruction) int32 {
 	var instructionsDone int32 = 0
 	var wg sync.WaitGroup
 	for {
@@ -118,11 +152,7 @@ func main() {
 		wg.Done()
 	}
 	wg.Wait()
-	if instructionsDone == 0 {
+	return instructionsDone
-		LogInfo("No instructions were processed")
-		os.Exit(1)
-	}
-	LogInfo("All done")
 }
 
 func IsPipeInput() bool {