CDRIVER-798 async_cmd checks for closed socket

Detects when server closes the connection on a call to ismaster.

Author: ajdavis

src/mongoc/mongoc-async-cmd.c

@@ -316,6 +316,13 @@ _mongoc_async_cmd_phase_recv_len (mongoc_async_cmd_t *acmd)
       return MONGOC_ASYNC_CMD_ERROR;
    }
 
+   if (bytes == 0) {
+      bson_set_error (&acmd->error, MONGOC_ERROR_STREAM,
+                      MONGOC_ERROR_STREAM_SOCKET,
+                      "Server closed connection.");
+      return MONGOC_ASYNC_CMD_ERROR;
+   }
+
    acmd->bytes_to_read -= bytes;
 
    if (!acmd->bytes_to_read) {
@@ -353,6 +360,13 @@ _mongoc_async_cmd_phase_recv_rpc (mongoc_async_cmd_t *acmd)
       return MONGOC_ASYNC_CMD_ERROR;
    }
 
+   if (bytes == 0) {
+      bson_set_error (&acmd->error, MONGOC_ERROR_STREAM,
+                      MONGOC_ERROR_STREAM_SOCKET,
+                      "Server closed connection.");
+      return MONGOC_ASYNC_CMD_ERROR;
+   }
+
    acmd->bytes_to_read -= bytes;
 
    if (!acmd->bytes_to_read) {

tests/test-mongoc-client.c

@@ -572,6 +572,8 @@ test_seed_list (bool rs,
    mongoc_topology_description_t *td;
    mongoc_read_prefs_t *primary_pref;
    uint32_t discovered_nodes_len;
+   int64_t start;
+   int64_t duration_usec;
    bson_t reply;
    bson_error_t error;
    uint32_t id;
@@ -594,11 +596,11 @@ test_seed_list (bool rs,
    uri = mongoc_uri_new (uri_str);
    assert (uri);
 
-   /* TODO: CDRIVER-798 this shouldn't be needed in order to fail promptly
-    * in single-threaded case. */
-   /* must be >= minHeartbeatFrequencyMS=500 or the "reconnect"
-    * case won't have time to succeed */
-   mongoc_uri_set_option_as_int32 (uri, "serverSelectionTimeoutMS", 1000);
+   if (pooled) {
+      /* must be >= minHeartbeatFrequencyMS=500 or the "reconnect"
+       * case won't have time to succeed */
+      mongoc_uri_set_option_as_int32 (uri, "serverSelectionTimeoutMS", 1000);
+   }
 
    if (rs) {
       mock_server_auto_ismaster (server,
@@ -637,12 +639,18 @@ test_seed_list (bool rs,
    primary_pref = mongoc_read_prefs_new (MONGOC_READ_PRIMARY);
 
    if (connection_option == CONNECT || connection_option == RECONNECT) {
+      start = bson_get_monotonic_time ();
+
       /* only localhost:port responds to initial discovery. the other seeds are
        * discarded from replica set topology, but remain for sharded. */
       ASSERT_OR_PRINT (mongoc_client_command_simple (
          client, "test", tmp_bson("{'foo': 1}"),
          primary_pref, &reply, &error), error);
 
+      /* discovery should be quick despite down servers, say < 100ms */
+      duration_usec = bson_get_monotonic_time () - start;
+      ASSERT_CMPINT ((int) (duration_usec / 1000), <, 100);
+
       bson_destroy (&reply);
 
       ASSERT_CMPINT (discovered_nodes_len, ==, (int) td->servers->items_len);
@@ -675,6 +683,12 @@ test_seed_list (bool rs,
          client, "test", tmp_bson("{'foo': 1}"),
          primary_pref, &reply, &error), error);
 
+      /* client waited for min heartbeat to pass before reconnecting, then
+       * reconnected quickly despite down servers, say < 100ms later */
+      duration_usec = bson_get_monotonic_time () - start;
+      ASSERT_CMPINT ((int) (duration_usec / 1000), <,
+                     MONGOC_TOPOLOGY_MIN_HEARTBEAT_FREQUENCY_MS + 100);
+
       bson_destroy (&reply);
 
       ASSERT_CMPINT (discovered_nodes_len, ==, (int) td->servers->items_len);