Add start of reloading client settings

Added new client settings paramter 'settingsReloadDelayInMinutes'
to handle how often the client settings are updated.
Added scheduler to call a new 'reloadClientSettings' method when
it's time to reload client settings.

CHANGELOG.md

@@ -6,6 +6,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Added
+- [2020-07-13] Added reloading client setting without stopping client by [@radonbark]
 
 ### Changed
 

src/main/kotlin/mdnet/base/Main.kt

@@ -19,25 +19,12 @@ along with this MangaDex@Home.  If not, see <http://www.gnu.org/licenses/>.
 package mdnet.base
 
 import ch.qos.logback.classic.LoggerContext
-import com.fasterxml.jackson.core.JsonParser
-import com.fasterxml.jackson.core.JsonProcessingException
-import com.fasterxml.jackson.databind.ObjectMapper
-import com.fasterxml.jackson.databind.SerializationFeature
-import com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException
-import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
-import com.fasterxml.jackson.module.kotlin.readValue
-import java.io.FileReader
-import java.io.FileWriter
-import java.io.IOException
-import java.util.regex.Pattern
 import kotlin.system.exitProcess
 import mdnet.BuildInfo
-import mdnet.base.settings.ClientSettings
 import org.slf4j.LoggerFactory
 
 object Main {
     private val LOGGER = LoggerFactory.getLogger(Main::class.java)
-    private val JACKSON: ObjectMapper = jacksonObjectMapper().enable(SerializationFeature.INDENT_OUTPUT).configure(JsonParser.Feature.ALLOW_COMMENTS, true)
 
     @JvmStatic
     fun main(args: Array<String>) {
@@ -68,25 +55,7 @@ object Main {
             dieWithError("Expected one argument: path to config file, or nothing")
         }
 
-        val settings = try {
-            JACKSON.readValue<ClientSettings>(FileReader(file))
-        } catch (e: UnrecognizedPropertyException) {
-            dieWithError("'${e.propertyName}' is not a valid setting")
-        } catch (e: JsonProcessingException) {
-            dieWithError(e)
-        } catch (ignored: IOException) {
-            ClientSettings().also {
-                LOGGER.warn("Settings file {} not found, generating file", file)
-                try {
-                    FileWriter(file).use { writer -> JACKSON.writeValue(writer, it) }
-                } catch (e: IOException) {
-                    dieWithError(e)
-                }
-            }
-        }.apply(::validateSettings)
-
-            LOGGER.info { "Client settings loaded: $settings" }
-        val client = MangaDexClient(settings)
+        val client = MangaDexClient(file)
         Runtime.getRuntime().addShutdownHook(Thread { client.shutdown() })
         client.runLoop()
     }
@@ -103,39 +72,4 @@ object Main {
         (LoggerFactory.getILoggerFactory() as LoggerContext).stop()
         exitProcess(1)
     }
-
-    private fun validateSettings(settings: ClientSettings) {
-        if (!isSecretValid(settings.clientSecret)) dieWithError("Config Error: API Secret is invalid, must be 52 alphanumeric characters")
-        if (settings.clientPort == 0) {
-            dieWithError("Config Error: Invalid port number")
-        }
-        if (settings.clientPort in Constants.RESTRICTED_PORTS) {
-            dieWithError("Config Error: Unsafe port number")
-        }
-        if (settings.maxCacheSizeInMebibytes < 1024) {
-            dieWithError("Config Error: Invalid max cache size, must be >= 1024 MiB (1GiB)")
-        }
-        if (settings.threads < 4) {
-            dieWithError("Config Error: Invalid number of threads, must be >= 4")
-        }
-        if (settings.maxMebibytesPerHour < 0) {
-            dieWithError("Config Error: Max bandwidth must be >= 0")
-        }
-        if (settings.maxKilobitsPerSecond < 0) {
-            dieWithError("Config Error: Max burst rate must be >= 0")
-        }
-        if (settings.gracefulShutdownWaitSeconds < 15) {
-            dieWithError("Config Error: Graceful shutdown wait be >= 15")
-        }
-        if (settings.webSettings != null) {
-            if (settings.webSettings.uiPort == 0) {
-                dieWithError("Config Error: Invalid UI port number")
-            }
-        }
-    }
-
-    private const val CLIENT_KEY_LENGTH = 52
-    private fun isSecretValid(clientSecret: String): Boolean {
-        return Pattern.matches("^[a-zA-Z0-9]{$CLIENT_KEY_LENGTH}$", clientSecret)
-    }
 }

src/main/kotlin/mdnet/base/MangaDexClient.kt

@@ -20,10 +20,14 @@ along with this MangaDex@Home.  If not, see <http://www.gnu.org/licenses/>.
 package mdnet.base
 
 import ch.qos.logback.classic.LoggerContext
+import com.fasterxml.jackson.core.JsonProcessingException
 import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException
 import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
 import com.fasterxml.jackson.module.kotlin.readValue
 import java.io.File
+import java.io.FileReader
+import java.io.FileWriter
 import java.io.IOException
 import java.time.Instant
 import java.util.*
@@ -32,6 +36,7 @@ import java.util.concurrent.Executors
 import java.util.concurrent.TimeUnit
 import java.util.concurrent.atomic.AtomicBoolean
 import java.util.concurrent.atomic.AtomicReference
+import java.util.regex.Pattern
 import mdnet.base.Main.dieWithError
 import mdnet.base.data.Statistics
 import mdnet.base.server.getServer
@@ -43,23 +48,28 @@ import mdnet.cache.HeaderMismatchException
 import org.http4k.server.Http4kServer
 import org.slf4j.LoggerFactory
 
+private const val CLIENT_KEY_LENGTH = 52
+
+// Exception class to handle when Client Settings have invalid values
+class ClientSettingsException(message: String) : Exception(message)
+
 sealed class State
 // server is not running
-object Uninitialized : State()
+data class Uninitialized(val clientSettings: ClientSettings) : State()
 // server has shut down
 object Shutdown : State()
 // server is in the process of shutting down
-data class GracefulShutdown(val lastRunning: Running, val counts: Int = 0, val nextState: State = Uninitialized, val action: () -> Unit = {}) : State()
+data class GracefulShutdown(val lastRunning: Running, val counts: Int = 0, val nextState: State = Uninitialized(lastRunning.clientSettings), val action: () -> Unit = {}) : State()
 // server is currently running
-data class Running(val server: Http4kServer, val settings: ServerSettings) : State()
-
-class MangaDexClient(private val clientSettings: ClientSettings) {
+data class Running(val server: Http4kServer, val settings: ServerSettings, val clientSettings: ClientSettings) : State()
+// clientSettings must only be accessed from the thread on the executorService
+class MangaDexClient(private val clientSettingsFile: String) {
     // this must remain singlethreaded because of how the state mechanism works
     private val executorService = Executors.newSingleThreadScheduledExecutor()
     // state must only be accessed from the thread on the executorService
-    private var state: State = Uninitialized
+    private var state: State
 
-    private val serverHandler: ServerHandler = ServerHandler(clientSettings)
+    private var serverHandler: ServerHandler
     private val statsMap: MutableMap<Instant, Statistics> = Collections
         .synchronizedMap(object : LinkedHashMap<Instant, Statistics>(240) {
             override fun removeEldestEntry(eldest: Map.Entry<Instant, Statistics>): Boolean {
@@ -74,6 +84,32 @@ class MangaDexClient(private val clientSettings: ClientSettings) {
     private val cache: DiskLruCache
 
     init {
+        // Read ClientSettings
+        val clientSettings = try {
+            readClientSettings()
+        } catch (e: UnrecognizedPropertyException) {
+            dieWithError("'${e.propertyName}' is not a valid setting")
+        } catch (e: JsonProcessingException) {
+            dieWithError(e)
+        } catch (ignored: IOException) {
+            ClientSettings().also {
+                LOGGER.warn { "Settings file $clientSettingsFile not found, generating file" }
+                try {
+                    FileWriter(clientSettingsFile).use { writer -> JACKSON.writeValue(writer, it) }
+                } catch (e: IOException) {
+                    dieWithError(e)
+                }
+            }
+        } catch (e: ClientSettingsException) {
+            dieWithError(e)
+        }
+
+        // Initialize things that depend on Client Settings
+        LOGGER.info { "Client settings loaded: $clientSettings" }
+        state = Uninitialized(clientSettings)
+        serverHandler = ServerHandler(clientSettings)
+
+        // Initialize everything else
         try {
             cache = DiskLruCache.open(
                 File("cache"), 1, 1,
@@ -94,11 +130,7 @@ class MangaDexClient(private val clientSettings: ClientSettings) {
     fun runLoop() {
         loginAndStartServer()
         statsMap[Instant.now()] = statistics.get()
-
-        if (clientSettings.webSettings != null) {
-            webUi = getUiServer(clientSettings.webSettings, statistics, statsMap)
-            webUi!!.start()
-        }
+        startWebUi()
         LOGGER.info { "Mangadex@Home Client initialized. Starting normal operation." }
 
         executorService.scheduleAtFixedRate({
@@ -140,11 +172,11 @@ class MangaDexClient(private val clientSettings: ClientSettings) {
             }
         }, 1, 1, TimeUnit.HOURS)
 
-        val timesToWait = clientSettings.gracefulShutdownWaitSeconds / 15
         executorService.scheduleAtFixedRate({
             try {
                 val state = this.state
                 if (state is GracefulShutdown) {
+                    val timesToWait = state.lastRunning.clientSettings.gracefulShutdownWaitSeconds / 15
                     when {
                         state.counts == 0 -> {
                             LOGGER.info { "Starting graceful shutdown" }
@@ -174,7 +206,7 @@ class MangaDexClient(private val clientSettings: ClientSettings) {
                     }
                 }
             } catch (e: Exception) {
-                LOGGER.warn("Main loop failed", e)
+                LOGGER.warn(e) { "Main loop failed" }
             }
         }, 15, 15, TimeUnit.SECONDS)
 
@@ -183,7 +215,7 @@ class MangaDexClient(private val clientSettings: ClientSettings) {
                 val state = this.state
                 if (state is Running) {
                     val currentBytesSent = statistics.get().bytesSent - lastBytesSent
-                    if (clientSettings.maxMebibytesPerHour != 0L && clientSettings.maxMebibytesPerHour * 1024 * 1024 /* MiB to bytes */ < currentBytesSent) {
+                    if (state.clientSettings.maxMebibytesPerHour != 0L && state.clientSettings.maxMebibytesPerHour * 1024 * 1024 /* MiB to bytes */ < currentBytesSent) {
                         LOGGER.info { "Shutting down server as hourly bandwidth limit reached" }
 
                         this.state = GracefulShutdown(lastRunning = state)
@@ -195,6 +227,18 @@ class MangaDexClient(private val clientSettings: ClientSettings) {
                 LOGGER.warn(e) { "Graceful shutdown checker failed" }
             }
         }, 45, 45, TimeUnit.SECONDS)
+
+        // Check every minute to see if client settings have changed
+        executorService.scheduleWithFixedDelay({
+            try {
+                val state = this.state
+                if (state is Running) {
+                        reloadClientSettings()
+                }
+            } catch (e: Exception) {
+                LOGGER.warn(e) { "Reload of ClientSettings failed" }
+            }
+        }, 60, 60, TimeUnit.SECONDS)
     }
 
     private fun pingControl() {
@@ -223,11 +267,11 @@ class MangaDexClient(private val clientSettings: ClientSettings) {
     }
 
     private fun loginAndStartServer() {
-        this.state as Uninitialized
+        val state = this.state as Uninitialized
 
         val serverSettings = serverHandler.loginToControl()
             ?: dieWithError("Failed to get a login response from server - check API secret for validity")
-        val server = getServer(cache, serverSettings, clientSettings, statistics, isHandled).start()
+        val server = getServer(cache, serverSettings, state.clientSettings, statistics, isHandled).start()
 
         if (serverSettings.latestBuild > Constants.CLIENT_BUILD) {
             LOGGER.warn {
@@ -235,7 +279,7 @@ class MangaDexClient(private val clientSettings: ClientSettings) {
             }
         }
 
-        state = Running(server, serverSettings)
+        this.state = Running(server, serverSettings, state.clientSettings)
         LOGGER.info { "Internal HTTP server was successfully started" }
     }
 
@@ -243,7 +287,7 @@ class MangaDexClient(private val clientSettings: ClientSettings) {
         serverHandler.logoutFromControl()
     }
 
-    private fun stopServer(nextState: State = Uninitialized) {
+    private fun stopServer(nextState: State) {
         val state = this.state.let {
             when (it) {
                 is Running ->
@@ -262,6 +306,32 @@ class MangaDexClient(private val clientSettings: ClientSettings) {
         this.state = nextState
     }
 
+    /**
+     * Starts the WebUI if the ClientSettings demand it.
+     * Because this method checks if the WebUI is needed,
+     * it can be safely called before checking yourself
+     */
+    private fun startWebUi() {
+        val state = this.state
+        // Grab the client settings if available
+        val clientSettings = state.let {
+            when (it) {
+                is Running ->
+                    it.clientSettings
+                is Uninitialized ->
+                    it.clientSettings
+                else ->
+                    null
+            }
+        }
+
+        // Only start the Web UI if the settings demand it
+        if (clientSettings?.webSettings != null) {
+            webUi = getUiServer(clientSettings.webSettings, statistics, statsMap)
+            webUi!!.start()
+        }
+    }
+
     fun shutdown() {
         LOGGER.info { "Mangadex@Home Client stopping" }
 
@@ -296,6 +366,126 @@ class MangaDexClient(private val clientSettings: ClientSettings) {
         (LoggerFactory.getILoggerFactory() as LoggerContext).stop()
     }
 
+    /**
+     * Reloads the client configuration and restarts the
+     * Web UI and/or the server if needed
+     */
+    private fun reloadClientSettings() {
+        val state = this.state as Running
+        LOGGER.info { "Reloading client settings" }
+        try {
+            val newSettings = readClientSettings()
+
+            if (newSettings == state.clientSettings) {
+                LOGGER.info { "Client Settings have not changed" }
+                return
+            }
+
+            // Setting loaded without issue. Figure out
+            // if there are changes that require a restart
+            val restartServer = newSettings.clientSecret != state.clientSettings.clientSecret ||
+                    newSettings.clientHostname != state.clientSettings.clientHostname ||
+                    newSettings.clientPort != state.clientSettings.clientPort ||
+                    newSettings.clientExternalPort != state.clientSettings.clientExternalPort ||
+                    newSettings.threads != state.clientSettings.threads ||
+                    newSettings.devSettings?.isDev != state.clientSettings.devSettings?.isDev
+            val stopWebUi = newSettings.webSettings != state.clientSettings.webSettings ||
+                    newSettings.webSettings?.uiPort != state.clientSettings.webSettings?.uiPort ||
+                    newSettings.webSettings?.uiHostname != state.clientSettings.webSettings?.uiHostname
+            val startWebUi = (stopWebUi && newSettings.webSettings != null)
+
+            // Stop the the WebUI if needed
+            if (stopWebUi) {
+                LOGGER.info { "Stopping WebUI to reload ClientSettings" }
+                webUi?.close()
+                webUi = null
+            }
+
+            if (restartServer) {
+                // If we are restarting the server
+                // We must do it gracefully and set
+                // the new settings later
+                LOGGER.info { "Stopping Server to reload ClientSettings" }
+
+                this.state = GracefulShutdown(state, nextState = Uninitialized(clientSettings = newSettings), action = {
+                    serverHandler = ServerHandler(newSettings)
+                    LOGGER.info { "Reloaded ClientSettings: $newSettings" }
+
+                    LOGGER.info { "Starting Server after reloading ClientSettings" }
+                    loginAndStartServer()
+
+                    // Start the WebUI if we had to stop it
+                    // and still want it
+                    if (startWebUi) {
+                        LOGGER.info { "Starting WebUI after reloading ClientSettings" }
+                        startWebUi()
+                        LOGGER.info { "Started WebUI after reloading ClientSettings" }
+                    }
+                })
+            } else {
+                // If we aren't restarting the server
+                // We can update the settings now
+                this.state = state.copy(clientSettings = newSettings)
+                serverHandler.setClientSettings(newSettings)
+                LOGGER.info { "Reloaded ClientSettings: $newSettings" }
+
+                // Start the WebUI if we had to stop it
+                // and still want it
+                if (startWebUi) {
+                    LOGGER.info { "Starting WebUI after reloading ClientSettings" }
+                    startWebUi()
+                    LOGGER.info { "Started WebUI after reloading ClientSettings" }
+                }
+            }
+        } catch (e: UnrecognizedPropertyException) {
+            LOGGER.warn { "Settings file is invalid: '$e.propertyName' is not a valid setting" }
+        } catch (e: JsonProcessingException) {
+            LOGGER.warn { "Settings file is invalid: $e.message" }
+        } catch (e: IOException) {
+            LOGGER.warn { "Settings file is could not be found: $e.message" }
+        } catch (e: ClientSettingsException) {
+            LOGGER.warn { "Can't reload client settings: $e.message" }
+        }
+    }
+
+    private fun validateSettings(settings: ClientSettings) {
+        if (!isSecretValid(settings.clientSecret)) throw ClientSettingsException("Config Error: API Secret is invalid, must be 52 alphanumeric characters")
+        if (settings.clientPort == 0) {
+            throw ClientSettingsException("Config Error: Invalid port number")
+        }
+        if (settings.clientPort in Constants.RESTRICTED_PORTS) {
+            throw ClientSettingsException("Config Error: Unsafe port number")
+        }
+        if (settings.maxCacheSizeInMebibytes < 1024) {
+            throw ClientSettingsException("Config Error: Invalid max cache size, must be >= 1024 MiB (1GiB)")
+        }
+        if (settings.threads < 4) {
+            throw ClientSettingsException("Config Error: Invalid number of threads, must be >= 4")
+        }
+        if (settings.maxMebibytesPerHour < 0) {
+            throw ClientSettingsException("Config Error: Max bandwidth must be >= 0")
+        }
+        if (settings.maxKilobitsPerSecond < 0) {
+            throw ClientSettingsException("Config Error: Max burst rate must be >= 0")
+        }
+        if (settings.gracefulShutdownWaitSeconds < 15) {
+            throw ClientSettingsException("Config Error: Graceful shutdown wait must be >= 15")
+        }
+        if (settings.webSettings != null) {
+            if (settings.webSettings.uiPort == 0) {
+                throw ClientSettingsException("Config Error: Invalid UI port number")
+            }
+        }
+    }
+
+    private fun readClientSettings(): ClientSettings {
+        return JACKSON.readValue<ClientSettings>(FileReader(clientSettingsFile)).apply(::validateSettings)
+    }
+
+    private fun isSecretValid(clientSecret: String): Boolean {
+        return Pattern.matches("^[a-zA-Z0-9]{$CLIENT_KEY_LENGTH}$", clientSecret)
+    }
+
     companion object {
         private val LOGGER = LoggerFactory.getLogger(MangaDexClient::class.java)
         private val JACKSON: ObjectMapper = jacksonObjectMapper()

src/main/kotlin/mdnet/base/ServerHandler.kt

@@ -40,7 +40,7 @@ object ServerHandlerJackson : ConfigurableJackson(
     .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
 )
 
-class ServerHandler(private val settings: ClientSettings) {
+class ServerHandler(private var settings: ClientSettings) {
     private val client = ApacheClient()
 
     fun logoutFromControl(): Boolean {
@@ -109,6 +109,10 @@ class ServerHandler(private val settings: ClientSettings) {
             SERVER_ADDRESS_DEV
     }
 
+    fun setClientSettings(clientSettings: ClientSettings) {
+        this.settings = clientSettings
+    }
+
     companion object {
         private val LOGGER = LoggerFactory.getLogger(ServerHandler::class.java)
         private val STRING_ANY_MAP_LENS = Body.auto<Map<String, Any>>().toLens()