[ADDED] natsOptions_SetFailRequestsOnDisconnect() option

src/conn.c

@@ -1203,6 +1203,7 @@ natsConn_disposeRespInfo(natsConnection *nc, respInfo *resp, bool needsLock)
             natsConn_Lock(nc);
 
         resp->closed = false;
+        resp->closedSts = NATS_OK;
         resp->removed = false;
         resp->msg = NULL;
 
@@ -1360,7 +1361,7 @@ natsConn_initResp(natsConnection *nc, natsMsgHandler cb)
 // This will clear any pending Request calls.
 // Lock is assumed to be held by the caller.
 static void
-_clearPendingRequestCalls(natsConnection *nc)
+_clearPendingRequestCalls(natsConnection *nc, natsStatus reason)
 {
     natsStrHashIter iter;
     void            *p = NULL;
@@ -1374,6 +1375,7 @@ _clearPendingRequestCalls(natsConnection *nc)
         respInfo *val = (respInfo*) p;
         natsMutex_Lock(val->mu);
         val->closed = true;
+        val->closedSts = reason;
         val->removed = true;
         natsCondition_Signal(val->cond);
         natsMutex_Unlock(val->mu);
@@ -1410,9 +1412,6 @@ _doReconnect(void *arg)
 
     natsConn_Lock(nc);
 
-    // Kick out all calls to natsConnection_Flush[Timeout]().
-    _clearPendingFlushRequests(nc);
-
     // Clear any error.
     nc->err         = NATS_OK;
     nc->errStr[0]   = '\0';
@@ -2031,6 +2030,13 @@ _processOpError(natsConnection *nc, natsStatus s, bool initialConnect)
             nc->sockCtx.fd = NATS_SOCK_INVALID;
         }
 
+        // Fail pending flush requests.
+        if (ls == NATS_OK)
+            _clearPendingFlushRequests(nc);
+        // If option set, also fail pending requests.
+        if ((ls == NATS_OK) && nc->opts->failRequestsOnDisconnect)
+            _clearPendingRequestCalls(nc, NATS_CONNECTION_DISCONNECTED);
+
         // Create the pending buffer to hold all write requests while we try
         // to reconnect.
         if (ls == NATS_OK)
@@ -2382,7 +2388,7 @@ _close(natsConnection *nc, natsConnStatus status, bool fromPublicClose, bool doC
     _clearPendingFlushRequests(nc);
 
     // Kick out any queued and blocking requests.
-    _clearPendingRequestCalls(nc);
+    _clearPendingRequestCalls(nc, NATS_CONNECTION_CLOSED);
 
     if (nc->ptmr != NULL)
         natsTimer_Stop(nc->ptmr);

src/nats.h

@@ -1534,6 +1534,23 @@ natsOptions_SetSendAsap(natsOptions *opts, bool sendAsap);
 NATS_EXTERN natsStatus
 natsOptions_UseOldRequestStyle(natsOptions *opts, bool useOldStyle);
 
+/** \brief Fails pending requests on disconnect event.
+ *
+ * If this option is enabled, all pending #natsConnection_Request() family
+ * calls will fail with the #NATS_CONNECTION_DISCONNECTED status.
+ *
+ * \note This does not apply to requests from connections that use the
+ * old style requests.
+ *
+ * @see natsOptions_UseOldRequestStyle
+ *
+ * @param opts the pointer to the #natsOptions object.
+ * @param failRequests a boolean indicating if pending requests should fail
+ * when a disconnect event occurs.
+ */
+NATS_EXTERN natsStatus
+natsOptions_SetFailRequestsOnDisconnect(natsOptions *opts, bool failRequests);
+
 /** \brief Sets if connection receives its own messages.
  *
  * This configures whether the server will echo back messages

src/natsp.h

@@ -261,6 +261,10 @@ struct __natsOptions
     // not rely on the flusher.
     bool                    sendAsap;
 
+    // If set to true, pending requests will fail with NATS_CONNECTION_DISCONNECTED
+    // when the library detects a disconnection.
+    bool                    failRequestsOnDisconnect;
+
     // NoEcho configures whether the server will echo back messages
     // that are sent on this connection if we also have matching subscriptions.
     // Note this is supported on servers >= version 1.2. Proto 1 or greater.
@@ -451,6 +455,7 @@ typedef struct __respInfo
     natsCondition       *cond;
     natsMsg             *msg;
     bool                closed;
+    natsStatus          closedSts;
     bool                removed;
     bool                pooled;
 

src/opts.c

@@ -1077,6 +1077,16 @@ natsOptions_UseOldRequestStyle(natsOptions *opts, bool useOldStype)
     return NATS_OK;
 }
 
+natsStatus
+natsOptions_SetFailRequestsOnDisconnect(natsOptions *opts, bool failRequests)
+{
+    LOCK_AND_CHECK_OPTIONS(opts, 0);
+    opts->failRequestsOnDisconnect = failRequests;
+    UNLOCK_OPTS(opts);
+
+    return NATS_OK;
+}
+
 static void
 _freeUserCreds(userCreds *uc)
 {

src/pub.c

@@ -492,7 +492,7 @@ natsConnection_RequestMsg(natsMsg **replyMsg, natsConnection *nc,
             {
                 // Set the correct error status that we return to the user
                 if (resp->closed)
-                    s = NATS_CONNECTION_CLOSED;
+                    s = resp->closedSts;
                 else
                     s = NATS_TIMEOUT;
             }

test/list.txt

@@ -78,6 +78,7 @@ IsReconnectingAndStatus
 ReconnectBufSize
 RetryOnFailedConnect
 NoPartialOnReconnect
+ReconnectFailsPendingRequests
 ErrOnConnectAndDeadlock
 ErrOnMaxPayloadLimit
 Auth

test/test.c

@@ -17121,6 +17121,70 @@ test_NoPartialOnReconnect(void)
     _stopServer(pid);
 }
 
+static void
+_stopServerInThread(void *closure)
+{
+    natsPid pid = *((natsPid*) closure);
+
+    nats_Sleep(150);
+    _stopServer(pid);
+}
+
+static void
+test_ReconnectFailsPendingRequest(void)
+{
+    natsStatus          s;
+    natsOptions         *opts = NULL;
+    natsConnection      *nc   = NULL;
+    natsSubscription    *sub  = NULL;
+    natsMsg             *msg  = NULL;
+    natsThread          *t    = NULL;
+    natsPid             pid   = NATS_INVALID_PID;
+    bool                failr = false;
+    int                 iter;
+
+    for (iter=1; iter<=2; iter++)
+    {
+        failr = (iter == 2 ? true : false);
+
+        test("Create options: ");
+        s = natsOptions_Create(&opts);
+        IFOK(s, natsOptions_SetFailRequestsOnDisconnect(opts, failr));
+        testCond(s == NATS_OK);
+
+        test("Start server: ");
+        pid = _startServer("nats://127.0.0.1:4222", "-p 4222", true);
+        CHECK_SERVER_STARTED(pid);
+        testCond(true);
+
+        test("Connect: ");
+        s = natsConnection_Connect(&nc, opts);
+        testCond(s == NATS_OK);
+
+        test("Create service provider: ");
+        s = natsConnection_SubscribeSync(&sub, nc, "requests");
+        testCond(s == NATS_OK);
+
+        test("Start thread that will stop server: ");
+        s = natsThread_Create(&t, _stopServerInThread, (void*) &pid);
+        testCond(s == NATS_OK);
+
+        test((failr ? "Fails due to disconnect: " : "Fails due to timeout: "));
+        s = natsConnection_RequestString(&msg, nc, "requests", "help", 300);
+        testCond(s == (failr ? NATS_CONNECTION_DISCONNECTED : NATS_TIMEOUT));
+
+        natsThread_Join(t);
+        natsThread_Destroy(t);
+        t = NULL;
+        natsSubscription_Destroy(sub);
+        sub = NULL;
+        natsConnection_Destroy(nc);
+        nc = NULL;
+        natsOptions_Destroy(opts);
+        opts = NULL;
+    }
+}
+
 static void
 test_HeadersNotSupported(void)
 {
@@ -20531,6 +20595,7 @@ static testInfo allTests[] =
     {"ReconnectBufSize",                test_ReconnectBufSize},
     {"RetryOnFailedConnect",            test_RetryOnFailedConnect},
     {"NoPartialOnReconnect",            test_NoPartialOnReconnect},
+    {"ReconnectFailsPendingRequests",   test_ReconnectFailsPendingRequest},
 
     {"ErrOnConnectAndDeadlock",         test_ErrOnConnectAndDeadlock},
     {"ErrOnMaxPayloadLimit",            test_ErrOnMaxPayloadLimit},