Application mutex

server/build.gradle.kts

@@ -12,7 +12,9 @@ plugins {
 }
 
 repositories {
-    mavenCentral()
+    maven {
+        url = uri("https://repo1.maven.org/maven2/")
+    }
     maven {
         url = uri("https://jitpack.io")
     }
@@ -53,7 +55,9 @@ dependencies {
 
     // api
     implementation("io.javalin:javalin:3.13.6")
-    implementation("com.fasterxml.jackson.core:jackson-databind:2.12.3")
+    // jackson version is tied to javalin, ref: `io.javalin.core.util.OptionalDependency`
+    implementation("com.fasterxml.jackson.core:jackson-databind:2.10.3")
+    implementation("com.fasterxml.jackson.module:jackson-module-kotlin:2.10.3")
 
     // Exposed ORM
     val exposedVersion = "0.31.1"

server/src/main/kotlin/ir/armor/tachidesk/server/JavalinSetup.kt

@@ -33,7 +33,7 @@ import ir.armor.tachidesk.impl.Source.getSourceList
 import ir.armor.tachidesk.impl.backup.BackupFlags
 import ir.armor.tachidesk.impl.backup.legacy.LegacyBackupExport.createLegacyBackup
 import ir.armor.tachidesk.impl.backup.legacy.LegacyBackupImport.restoreLegacyBackup
-import ir.armor.tachidesk.server.internal.About.getAbout
+import ir.armor.tachidesk.server.impl_internal.About.getAbout
 import ir.armor.tachidesk.server.util.openInBrowser
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers

server/src/main/kotlin/ir/armor/tachidesk/server/ServerSetup.kt

@@ -10,6 +10,7 @@ package ir.armor.tachidesk.server
 import ch.qos.logback.classic.Level
 import eu.kanade.tachiyomi.App
 import ir.armor.tachidesk.model.database.databaseUp
+import ir.armor.tachidesk.server.util.AppMutex.handleAppMutex
 import ir.armor.tachidesk.server.util.systemTray
 import mu.KotlinLogging
 import org.kodein.di.DI
@@ -36,7 +37,7 @@ class ApplicationDirs(
 
 val serverConfig: ServerConfig by lazy { GlobalConfigManager.module() }
 
-val systemTray by lazy { systemTray() }
+val systemTrayInstance by lazy { systemTray() }
 
 val androidCompat by lazy { AndroidCompat() }
 
@@ -66,6 +67,8 @@ fun applicationSetup() {
         ServerConfig.register(GlobalConfigManager.config)
     )
 
+    handleAppMutex()
+
     // Load config API
     DI.global.addImport(ConfigKodeinModule().create())
     // Load Android compatibility dependencies
@@ -97,7 +100,7 @@ fun applicationSetup() {
     // create system tray
     if (serverConfig.systemTrayEnabled) {
         try {
-            systemTray
+            systemTrayInstance
         } catch (e: Throwable) { // cover both java.lang.Exception and java.lang.Error
             e.printStackTrace()
         }

server/src/main/kotlin/ir/armor/tachidesk/server/impl_internal/About.kt

@@ -1,4 +1,4 @@
-package ir.armor.tachidesk.server.internal
+package ir.armor.tachidesk.server.impl_internal
 
 /*
  * Copyright (C) Contributors to the Suwayomi project

server/src/main/kotlin/ir/armor/tachidesk/server/util/AppExit.kt

@@ -0,0 +1,13 @@
+package ir.armor.tachidesk.server.util
+
+import kotlin.system.exitProcess
+
+enum class ExitCode(val code: Int) {
+    Success(0),
+    MutexCheckFailedTachideskRunning(1),
+    MutexCheckFailedAnotherAppRunning(2);
+}
+
+fun shutdownApp(exitCode: ExitCode) {
+    exitProcess(exitCode.code)
+}

server/src/main/kotlin/ir/armor/tachidesk/server/util/AppMutex.kt

@@ -0,0 +1,71 @@
+package ir.armor.tachidesk.server.util
+
+/*
+ * Copyright (C) Contributors to the Suwayomi project
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+import io.javalin.plugin.json.JavalinJackson
+import ir.armor.tachidesk.server.impl_internal.AboutDataClass
+import ir.armor.tachidesk.server.serverConfig
+import ir.armor.tachidesk.server.util.AppMutex.AppMutexStat.Clear
+import ir.armor.tachidesk.server.util.AppMutex.AppMutexStat.OtherApplicationRunning
+import ir.armor.tachidesk.server.util.AppMutex.AppMutexStat.TachideskInstanceRunning
+import mu.KotlinLogging
+import okhttp3.OkHttpClient
+import okhttp3.Request.Builder
+import java.io.IOException
+import java.util.concurrent.TimeUnit
+
+object AppMutex {
+    private val logger = KotlinLogging.logger {}
+
+    private enum class AppMutexStat(val stat: Int) {
+        Clear(0),
+        TachideskInstanceRunning(1),
+        OtherApplicationRunning(2)
+    }
+
+    private val appIP = if (serverConfig.ip == "0.0.0.0") "127.0.0.1" else serverConfig.ip
+
+    private fun checkAppMutex(): AppMutexStat {
+        val client = OkHttpClient.Builder()
+            .connectTimeout(200, TimeUnit.MILLISECONDS)
+            .build()
+
+        val request = Builder()
+            .url("http://$appIP:${serverConfig.port}/api/v1/about/")
+            .build()
+
+        val response = try {
+            client.newCall(request).execute().use { response -> response.body!!.string() }
+        } catch (e: IOException) {
+            return AppMutexStat.Clear
+        }
+
+        return try {
+            JavalinJackson.fromJson(response, AboutDataClass::class.java)
+            AppMutexStat.TachideskInstanceRunning
+        } catch (e: IOException) {
+            AppMutexStat.OtherApplicationRunning
+        }
+    }
+
+    fun handleAppMutex() {
+        when (checkAppMutex()) {
+            Clear -> {
+                logger.info("Mutex status is clear, Resuming startup.")
+            }
+            TachideskInstanceRunning -> {
+                logger.info("Another instance of Tachidesk is running on $appIP:${serverConfig.port}, Aborting.")
+                shutdownApp(ExitCode.MutexCheckFailedTachideskRunning)
+            }
+            OtherApplicationRunning -> {
+                logger.error("A non Tachidesk application is running on $appIP:${serverConfig.port}, Aborting.")
+                shutdownApp(ExitCode.MutexCheckFailedAnotherAppRunning)
+            }
+        }
+    }
+}

server/src/main/kotlin/ir/armor/tachidesk/server/util/SystemTray.kt

@@ -15,7 +15,7 @@ import dorkbox.util.Desktop
 import ir.armor.tachidesk.server.BuildConfig
 import ir.armor.tachidesk.server.ServerConfig
 import ir.armor.tachidesk.server.serverConfig
-import kotlin.system.exitProcess
+import ir.armor.tachidesk.server.util.ExitCode.Success
 
 fun openInBrowser() {
     try {
@@ -53,8 +53,7 @@ fun systemTray(): SystemTray? {
 
         mainMenu.add(
             MenuItem("Quit") {
-                systemTray.shutdown()
-                exitProcess(0)
+                shutdownApp(Success)
             }
         )