Set up rotation of logs.

main.go

@@ -7,18 +7,19 @@ import (
 	"os"
 )
 
-const logFilePath = "/tmp/frc-radio-api.log"
+const (
+	// Path of the current log file.
+	logFilePath = "/root/frc-radio-api.log"
+
+	// Path of the old log file, which is rotated when the current log file gets too big.
+	oldLogFilePath = "/root/frc-radio-api.log.old"
+
+	// Maximum size of the current log file in bytes.
+	logFileMaxSizeBytes = 3 * 1 << 19 // 1.5 MB
+)
 
 func main() {
-	// Set up logging to file.
-	logFile, err := os.OpenFile(logFilePath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0666)
-	if err == nil {
-		defer logFile.Close()
-		log.SetOutput(logFile)
-	} else {
-		log.Printf("error opening log file; logging to stdout instead: %v", err)
-	}
-	log.Println("Starting FRC Radio API...")
+	setupLogging()
 
 	radio := radio.NewRadio()
 
@@ -29,3 +30,25 @@ func main() {
 	// Run the radio event loop in the main thread.
 	radio.Run()
 }
+
+// setupLogging sets up logging to a file, or to stdout if the file can't be opened.
+func setupLogging() {
+	// Rotate the log file if the current one is too big.
+	if fileInfo, err := os.Stat(logFilePath); err == nil {
+		if fileInfo.Size() >= logFileMaxSizeBytes {
+			if err := os.Rename(logFilePath, oldLogFilePath); err != nil {
+				log.Printf("error rotating log file: %v", err)
+			}
+		}
+	}
+
+	logFile, err := os.OpenFile(logFilePath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0666)
+	if err == nil {
+		defer logFile.Close()
+		log.SetOutput(logFile)
+	} else {
+		log.Printf("error opening log file; logging to stdout instead: %v", err)
+	}
+	log.Println("Starting FRC Radio API...")
+
+}