feat(logging): add size-limited log rotation via lumberjack

DEVELOPMENT.md

@@ -89,7 +89,7 @@ Now edit files in `ui/src/` and see changes live in your browser!
 
 ```bash
 ssh root@192.168.1.100
-tail -f /userdata/jetkvm/last.log
+tail -f /userdata/jetkvm/app.log
 ```
 
 ---
@@ -200,11 +200,11 @@ ssh root@192.168.1.100 ps aux | grep jetkvm
 
 ### View live logs
 
-The file `/userdata/jetkvm/last.log` contains the JetKVM logs. You can view live logs with:
+The file `/userdata/jetkvm/app.log` contains the JetKVM logs. You can view live logs with:
 
 ```bash
 ssh root@192.168.1.100
-tail -f /userdata/jetkvm/last.log
+tail -f /userdata/jetkvm/app.log
 ```
 
 ### Reset everything (if stuck)
@@ -230,7 +230,7 @@ The code and GDB server will be deployed automatically.
 1. Deploy your changes: `./dev_deploy.sh -r <IP>`
 2. Open browser: `http://<IP>`
 3. Test your feature
-4. Check logs: `ssh root@<IP> tail -f /userdata/jetkvm/last.log`
+4. Check logs: `ssh root@<IP> tail -f /userdata/jetkvm/app.log`
 
 ### Automated Testing
 
@@ -425,7 +425,7 @@ export JETKVM_PROXY_URL="ws://<IP>"
 
 ## Need Help?
 
-1. **Check logs first:** `ssh root@<IP> tail -f /userdata/jetkvm/last.log`
+1. **Check logs first:** `ssh root@<IP> tail -f /userdata/jetkvm/app.log`
 2. **Search issues:** [GitHub Issues](https://github.com/jetkvm/kvm/issues)
 3. **Ask on Discord:** [JetKVM Discord](https://jetkvm.com/discord)
 4. **Read docs:** [JetKVM Documentation](https://jetkvm.com/docs)

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/coder/websocket v1.8.14
 	github.com/coreos/go-oidc/v3 v3.16.0
 	github.com/creack/pty v1.1.24
+	github.com/eclipse/paho.mqtt.golang v1.5.1
 	github.com/erikdubbelboer/gspt v0.0.0-20210805194459-ce36a5128377
 	github.com/fsnotify/fsnotify v1.9.0
 	github.com/gin-contrib/logger v1.2.6
@@ -41,6 +42,7 @@ require (
 	golang.org/x/sys v0.37.0
 	google.golang.org/grpc v1.76.0
 	google.golang.org/protobuf v1.36.10
+	gopkg.in/natefinch/lumberjack.v2 v2.2.1
 )
 
 replace github.com/pojntfx/go-nbd v0.3.2 => github.com/chemhack/go-nbd v0.0.0-20241006125820-59e45f5b1e7b
@@ -54,7 +56,6 @@ require (
 	github.com/cloudwego/base64x v0.1.6 // indirect
 	github.com/creack/goselect v0.1.2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/eclipse/paho.mqtt.golang v1.5.1 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.9 // indirect
 	github.com/gin-contrib/sse v1.1.0 // indirect
 	github.com/go-jose/go-jose/v4 v4.1.3 // indirect

go.sum

@@ -265,6 +265,8 @@ google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
+gopkg.in/natefinch/lumberjack.v2 v2.2.1 h1:bBRl1b0OH9s/DuPhuXpNl+VtCaJXFZ5/uEFST95x9zc=
+gopkg.in/natefinch/lumberjack.v2 v2.2.1/go.mod h1:YD8tP3GAjkrDg1eZH7EGmyESg/lsYskCTPBJVb9jqSc=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/logging/logger.go

@@ -4,11 +4,13 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"path/filepath"
 	"strings"
 	"sync"
 	"time"
 
 	"github.com/rs/zerolog"
+	"gopkg.in/natefinch/lumberjack.v2"
 )
 
 type Logger struct {
@@ -24,6 +26,9 @@ type Logger struct {
 
 const (
 	defaultLogLevel = zerolog.ErrorLevel
+	AppLogPath      = "/userdata/jetkvm/app.log"
+	appLogMaxSizeMB = 50
+	appLogBackups   = 1
 )
 
 type logOutput struct {
@@ -44,6 +49,22 @@ func (w *logOutput) Write(p []byte) (n int, err error) {
 	return len(p), nil
 }
 
+func newDefaultLogOutput() io.Writer {
+	writers := []io.Writer{consoleLogOutput, fileLogOutput}
+
+	dir := filepath.Dir(AppLogPath)
+	if _, err := os.Stat(dir); err == nil {
+		writers = append(writers, &lumberjack.Logger{
+			Filename:   AppLogPath,
+			MaxSize:    appLogMaxSizeMB,
+			MaxBackups: appLogBackups,
+			Compress:   false,
+		})
+	}
+
+	return zerolog.MultiLevelWriter(writers...)
+}
+
 var (
 	consoleLogOutput io.Writer = zerolog.ConsoleWriter{
 		Out:           os.Stdout,
@@ -61,7 +82,7 @@ var (
 		},
 	}
 	fileLogOutput    io.Writer = &logOutput{mu: &sync.Mutex{}}
-	defaultLogOutput           = zerolog.MultiLevelWriter(consoleLogOutput, fileLogOutput)
+	defaultLogOutput           = newDefaultLogOutput()
 
 	zerologLevels = map[string]zerolog.Level{
 		"DISABLE": zerolog.Disabled,

internal/supervisor/consts.go

@@ -6,7 +6,7 @@ const (
 	ErrorDumpDir      = "/userdata/jetkvm/crashdump" // The error dump directory is the directory where the error dumps are stored
 	ErrorDumpLastFile = "last-crash.log"             // The error dump last file is the last error dump file
 	ErrorDumpTemplate = "jetkvm-%s.log"              // The error dump template is the template for the error dump file
-	AppLogPath        = "/userdata/jetkvm/last.log"  // The application stdout/stderr log file
+	AppLogPath        = "/userdata/jetkvm/app.log"   // The application log file (managed by lumberjack)
 
 	FailsafeReasonVideoMaxRestartAttemptsReached = "failsafe::video.max_restart_attempts_reached"
 )

main.go

@@ -56,7 +56,7 @@ func Main() {
 		logger.Warn().Err(err).Msg("failed to get local version")
 	}
 
-	logger.Info().
+	logger.Log().
 		Interface("system_version", systemVersionLocal).
 		Interface("app_version", appVersionLocal).
 		Msg("starting JetKVM")

ui/e2e/global-teardown.ts

@@ -20,7 +20,7 @@ export default async function globalTeardown() {
     fs.mkdirSync(logDir, { recursive: true });
 
     const logs: Record<string, string> = {
-      "device-last.log": "cat /userdata/jetkvm/last.log",
+      "device-app.log": "cat /userdata/jetkvm/app.log",
       "device-config.json": "cat /userdata/kvm_config.json",
       "device-dmesg.txt": "dmesg | tail -200",
     };

ui/e2e/helpers.ts

@@ -732,7 +732,7 @@ export async function restartAppViaSSH(): Promise<void> {
   await sshExec("killall jetkvm_app", true);
   await new Promise(r => setTimeout(r, 500));
   await sshExec(
-    "setsid env LD_LIBRARY_PATH=/oem/usr/lib:/oem/lib /userdata/jetkvm/bin/jetkvm_app > /userdata/jetkvm/last.log 2>&1 &",
+    "setsid env LD_LIBRARY_PATH=/oem/usr/lib:/oem/lib /userdata/jetkvm/bin/jetkvm_app > /dev/null 2>&1 &",
     true,
   );
   await new Promise(r => setTimeout(r, 1000));

ui/e2e/log-rotation.spec.ts

@@ -0,0 +1,59 @@
+import { test, expect } from "@playwright/test";
+
+import { sshExec, getDeviceHost, waitForDeviceReady } from "./helpers";
+
+const APP_LOG_PATH = "/userdata/jetkvm/app.log";
+const MAX_LOG_SIZE_BYTES = 50 * 1024 * 1024; // 50 MB
+
+test.describe("Log rotation and diagnostics", () => {
+  test("app.log exists and contains version banner", async () => {
+    const ls = await sshExec(`ls -la ${APP_LOG_PATH}`);
+    expect(ls).toContain("app.log");
+
+    const appVersion = await sshExec(`grep "app_version" ${APP_LOG_PATH}`);
+    expect(appVersion.trim().length).toBeGreaterThan(0);
+
+    const systemVersion = await sshExec(`grep "system_version" ${APP_LOG_PATH}`);
+    expect(systemVersion.trim().length).toBeGreaterThan(0);
+  });
+
+  test("app.log is within the size limit", async () => {
+    const sizeStr = await sshExec(`stat -c%s ${APP_LOG_PATH}`);
+    const size = parseInt(sizeStr.trim(), 10);
+    expect(size).toBeGreaterThan(0);
+    expect(size).toBeLessThan(MAX_LOG_SIZE_BYTES);
+  });
+
+  test("diagnostics zip contains app.log", async ({ page }) => {
+    const host = getDeviceHost();
+    const resp = await page.request.get(`http://${host}/diagnostics`);
+    expect(resp.status()).toBe(200);
+
+    const body = await resp.body();
+    expect(body.length).toBeGreaterThan(0);
+
+    const zipContent = body.toString("binary");
+    expect(zipContent).toContain("app.log");
+  });
+
+  test("app.log continues growing after restart", async () => {
+    test.setTimeout(120_000);
+
+    const host = getDeviceHost();
+
+    const beforeLines = await sshExec(`wc -l < ${APP_LOG_PATH}`);
+    const lineCountBefore = parseInt(beforeLines.trim(), 10);
+
+    await sshExec("killall jetkvm_app", true);
+    await new Promise(r => setTimeout(r, 2000));
+
+    await waitForDeviceReady(host, 60000);
+
+    const afterLines = await sshExec(`wc -l < ${APP_LOG_PATH}`);
+    const lineCountAfter = parseInt(afterLines.trim(), 10);
+    expect(lineCountAfter).toBeGreaterThan(lineCountBefore);
+
+    const versionAfterRestart = await sshExec(`grep "app_version" ${APP_LOG_PATH}`);
+    expect(versionAfterRestart.trim().length).toBeGreaterThan(0);
+  });
+});