Unblock queues on shutdown or errors

source/tristanable/exceptions.d

@@ -10,6 +10,23 @@ import std.conv : to;
  */
 public enum ErrorType
 {
+    /**
+     * Unset
+     */
+    UNSET,
+
+    /**
+     * If the manager has already
+     * been shutdown
+     */
+    MANAGER_SHUTDOWN,
+
+    /**
+     * If the watcher has failed
+     * to stay alive
+     */
+    WATCHER_FAILED,
+
     /**
      * If the requested queue could not be found
      */

source/tristanable/manager/manager.d

@@ -93,10 +93,69 @@ public class Manager
      * Stops the management of the socket, resulting
      * in ending the updating of queues and closing
      * the underlying connection
+     *
+     * Calling this will also unblock any calls that
+     * were blocking whilst doing a `dequeue()`
      */
     public void stop()
     {
+        /* Stop with the given reason */
+        stop(ErrorType.MANAGER_SHUTDOWN);
+    }
+
+    /** 
+     * Only called by the `Watcher` and for
+     * the purpose of setting a custom error
+     * type.
+     *
+     * Called when the network read fails
+     */
+    void stop_FailedWatcher()
+    {
+        /* Stop with the given reason */
+        stop(ErrorType.WATCHER_FAILED);
+    }
+
+    /** 
+     * Stops the watcher service and then
+     * unblocks all calls to `dequeue()`
+     * by shutting down each `Queue`
+     *
+     * Params:
+     *   reason = the reason for the
+     * shutdown
+     */
+    private void stop(ErrorType reason)
+    {
+        /* Stop the watcher */
         watcher.shutdown();
+
+        /* Unblock all `dequeue()` calls */
+        shutdownAllQueues(reason);
+    }
+
+    /** 
+     * Shuts down all registered queues
+     */
+    protected void shutdownAllQueues(ErrorType reason)
+    {
+        /* Lock the queue of queues */
+        queuesLock.lock();
+
+        /* On return or error */
+        scope(exit)
+        {
+            /* Unlock the queue of queues */
+            queuesLock.unlock();
+        }
+
+        // TODO: Shutdown default queue - see mtsafety
+
+        /* Shutdown each queue */
+        foreach(Queue queue; this.queues)
+        {
+            queue.shutdownQueue(reason);
+        }
     }
 
     /**

source/tristanable/manager/watcher.d

@@ -128,6 +128,19 @@ public class Watcher : Thread
                 break;
             }
         }
+
+        version(unittest) { writeln("Exited watcher loop"); }
+
+        // NOTE: This will also be run on normal user-initiated `stop()`
+        // ... but will just try shutdown an alreayd shutdown manager
+        // ... again and try shut our already-closed river stream
+        // Shutdown and unblock all `dequeue()` calls
+
+        // TODO: A problem is user-initiated could cause this to trugger first and then throw
+        // ... actually with a WATCHER_FAILED - we should maybe use one error
+        // ... or find a smart way to have the right flow go off - split up calls
+        // ... more?
+        this.manager.stop_FailedWatcher();
     }
 
     /** 
@@ -141,17 +154,20 @@ public class Watcher : Thread
     }
 }
 
+version(unittest)
+{
+    import std.socket;
+    import std.stdio;
+    import core.thread;
+}
+
 /** 
  * Set up a server which will send some tagged messages to us (the client),
  * where we have setup a `Manager` to watch the queues with tags `42` and `69`,
  * we then dequeue some messages from both queus. Finally, we shut down the manager.
  */
 unittest
 {
-    import std.socket;
-    import std.stdio;
-    import core.thread;
-
     Address serverAddress = parseAddress("::1", 0);
     Socket server = new Socket(AddressFamily.INET6, SocketType.STREAM, ProtocolType.TCP);
     server.bind(serverAddress);
@@ -294,4 +310,224 @@ unittest
 
     /* Stop the manager */
     manager.stop();
+}
+
+/**
+ * Setup a `Manager` and then block on a `dequeue()`
+ * but from another thread shutdown the `Manager`.
+ *
+ * This is to test the exception triggering mechanism
+ * for such a case
+ */
+unittest
+{
+    writeln("<<<<< Test 3 start >>>>>");
+
+    Address serverAddress = parseAddress("::1", 0);
+    Socket server = new Socket(AddressFamily.INET6, SocketType.STREAM, ProtocolType.TCP);
+    server.bind(serverAddress);
+    server.listen(0);
+
+    class ServerThread : Thread
+    {
+        this()
+        {
+            super(&worker);
+        }
+
+        private void worker()
+        {
+            Socket clientSocket = server.accept();
+            BClient bClient = new BClient(clientSocket);
+
+            Thread.sleep(dur!("seconds")(7));
+            writeln("Server start");
+
+            /** 
+             * Create a tagged message to send
+             *
+             * tag 42 payload Cucumber 😳️
+             */
+            TaggedMessage message = new TaggedMessage(42, cast(byte[])"Cucumber 😳️");
+            byte[] tEncoded = message.encode();
+            writeln("server send status: ", bClient.sendMessage(tEncoded));
+
+            writeln("server send [done]");
+
+            sleep(dur!("seconds")(15));
+
+            writeln("Server ending");
+        }
+    }
+
+    ServerThread serverThread = new ServerThread();
+    serverThread.start();
+
+    Socket client = new Socket(AddressFamily.INET6, SocketType.STREAM, ProtocolType.TCP);
+
+    writeln(server.localAddress);
+
+
+    Manager manager = new Manager(client);
+
+    Queue sixtyNine = new Queue(69);
+
+    manager.registerQueue(sixtyNine);
+
+
+    /* Connect our socket to the server */
+    client.connect(server.localAddress);
+
+    /* Start the manager and let it manage the socket */
+    manager.start();
+
+
+    // The failing exception
+    TristanableException failingException;
+
+    class DequeueThread : Thread
+    {
+        private Queue testQueue;
+
+        this(Queue testQueue)
+        {
+            super(&worker);
+            this.testQueue = testQueue;
+        }
+
+        public void worker()
+        {
+            try
+            {
+                writeln("dequeuThread: Before dequeue()");
+                this.testQueue.dequeue();
+                writeln("dequeueThread: After dequeue() [should not get here]");
+            }
+            catch(TristanableException e)
+            {
+                writeln("Got tristanable exception during dequeue(): "~e.toString());
+
+                // TODO: Fliup boolean is all cgood and assret it later
+                failingException = e;
+            }
+        }
+    }
+
+    DequeueThread dequeueThread = new DequeueThread(sixtyNine);
+    dequeueThread.start();
+
+    // Stop the manager
+    manager.stop();
+    writeln("drop");
+
+    // Wait for the dequeueing thread to stop
+    dequeueThread.join();
+
+    // Check condition
+    assert(failingException !is null);
+    assert(failingException.getError() == ErrorType.MANAGER_SHUTDOWN);
+}
+
+/**
+ * Setup a server which dies (kills its connection to us)
+ * midway whilst we are doing a `dequeue()`
+ *
+ * This is to test the exception triggering mechanism
+ * for such a case
+ */
+unittest
+{
+    writeln("<<<<< Test 4 start >>>>>");
+
+    Address serverAddress = parseAddress("::1", 0);
+    Socket server = new Socket(AddressFamily.INET6, SocketType.STREAM, ProtocolType.TCP);
+    server.bind(serverAddress);
+    server.listen(0);
+
+    class ServerThread : Thread
+    {
+        this()
+        {
+            super(&worker);
+        }
+
+        private void worker()
+        {
+            Socket clientSocket = server.accept();
+            BClient bClient = new BClient(clientSocket);
+
+            Thread.sleep(dur!("seconds")(7));
+            writeln("Server start");
+
+            sleep(dur!("seconds")(15));
+
+            writeln("Server ending");
+
+            // Close the connection
+            bClient.close();
+        }
+    }
+
+    ServerThread serverThread = new ServerThread();
+    serverThread.start();
+
+    Socket client = new Socket(AddressFamily.INET6, SocketType.STREAM, ProtocolType.TCP);
+
+    writeln(server.localAddress);
+
+
+    Manager manager = new Manager(client);
+
+    Queue sixtyNine = new Queue(69);
+
+    manager.registerQueue(sixtyNine);
+
+
+    /* Connect our socket to the server */
+    client.connect(server.localAddress);
+
+    /* Start the manager and let it manage the socket */
+    manager.start();
+
+
+    // The failing exception
+    TristanableException failingException;
+
+    class DequeueThread : Thread
+    {
+        private Queue testQueue;
+
+        this(Queue testQueue)
+        {
+            super(&worker);
+            this.testQueue = testQueue;
+        }
+
+        public void worker()
+        {
+            try
+            {
+                writeln("dequeuThread: Before dequeue()");
+                this.testQueue.dequeue();
+                writeln("dequeueThread: After dequeue() [should not get here]");
+            }
+            catch(TristanableException e)
+            {
+                writeln("Got tristanable exception during dequeue(): "~e.toString());
+
+                // TODO: Fliup boolean is all cgood and assret it later
+                failingException = e;
+            }
+        }
+    }
+
+    DequeueThread dequeueThread = new DequeueThread(sixtyNine);
+    dequeueThread.start();
+
+    // Wait for the dequeueing thread to stop
+    dequeueThread.join();
+
+    // Check condition
+    assert(failingException !is null);
+    assert(failingException.getError() == ErrorType.WATCHER_FAILED);
 }