add serviceId to server description; reject non load balanced connections

Author: kevinAlbs

src/libmongoc/doc/errors.rst

@@ -31,6 +31,8 @@ Many C Driver functions report errors by returning ``false`` or -1 and filling o
 +-----------------------------------------+---------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
 |                                         | ``MONGOC_ERROR_CLIENT_INVALID_ENCRYPTION_STATE``                                                                                | Failure related to Client-Side Field Level Encryption.                                                                                                                                                                                                                                                                                     |
 +-----------------------------------------+---------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+|                                         | ``MONGOC_ERROR_CLIENT_INVALID_LOAD_BALANCER``                                                                                   | You attempted to connect to a MongoDB server behind a load balancer, but the server does not advertise load balanced support.                                                                                                                                                                                                              |
++-----------------------------------------+---------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
 | ``MONGOC_ERROR_STREAM``                 | ``MONGOC_ERROR_STREAM_NAME_RESOLUTION``                                                                                         | DNS failure.                                                                                                                                                                                                                                                                                                                               |
 +-----------------------------------------+---------------------------------------------------------------------------------------------------------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
 |                                         | ``MONGOC_ERROR_STREAM_SOCKET``                                                                                                  | Timeout communicating with server, or connection closed.                                                                                                                                                                                                                                                                                   |

src/libmongoc/src/mongoc/mongoc-cluster.c

@@ -2281,6 +2281,24 @@ _mongoc_cluster_stream_for_server (mongoc_cluster_t *cluster,
    }
 
    // LBTODO: if this is a load balanced topology and the server stream does not have a service id, disconnect and return an error.
+   bson_mutex_lock (&topology->mutex);
+   if (topology->description.type == MONGOC_TOPOLOGY_LOAD_BALANCED) {
+      bson_oid_t service_id;
+
+      if (!mongoc_server_description_service_id (server_stream->sd,
+                                                 &service_id)) {
+         bson_set_error (error,
+                         MONGOC_ERROR_CLIENT,
+                         MONGOC_ERROR_CLIENT_INVALID_LOAD_BALANCER,
+                         "Driver attempted to initialize in load balancing "
+                         "mode, but the server does not support this mode.");
+         mongoc_server_stream_cleanup (server_stream);
+         mongoc_cluster_disconnect_node (cluster, server_id);
+         bson_mutex_unlock (&topology->mutex);
+         return NULL;
+      }
+   }
+   bson_mutex_unlock (&topology->mutex);
 
    RETURN (server_stream);
 }

src/libmongoc/src/mongoc/mongoc-error.h

@@ -131,7 +131,9 @@ typedef enum {
    MONGOC_ERROR_CLIENT_API_ALREADY_SET,
    MONGOC_ERROR_CLIENT_API_FROM_POOL,
    MONGOC_ERROR_POOL_API_ALREADY_SET,
-   MONGOC_ERROR_POOL_API_TOO_LATE
+   MONGOC_ERROR_POOL_API_TOO_LATE,
+
+   MONGOC_ERROR_CLIENT_INVALID_LOAD_BALANCER,
 } mongoc_error_code_t;
 
 MONGOC_EXPORT (bool)

src/libmongoc/src/mongoc/mongoc-server-description-private.h

@@ -112,6 +112,7 @@ struct _mongoc_server_description_t {
    pre-4.2 server.
    */
    uint32_t generation;
+   bson_oid_t service_id;
 };
 
 void
@@ -183,4 +184,10 @@ void
 mongoc_server_description_set_topology_version (mongoc_server_description_t *sd,
                                                 const bson_t *tv);
 
+/* If a service_id is set on the topology description, copies it to @oid and returns true.
+ * Otherwise returns false and zeros out oid.
+ */
+bool
+mongoc_server_description_service_id (const mongoc_server_description_t *description, bson_oid_t *oid);
+
 #endif

src/libmongoc/src/mongoc/mongoc-server-description.c

@@ -92,6 +92,7 @@ mongoc_server_description_reset (mongoc_server_description_t *sd)
    sd->current_primary = NULL;
    sd->set_version = MONGOC_NO_SET_VERSION;
    bson_oid_copy_unsafe (&kObjectIdZero, &sd->election_id);
+   bson_oid_copy_unsafe (&kObjectIdZero, &sd->service_id);
 }
 
 /*
@@ -723,8 +724,11 @@ mongoc_server_description_handle_hello (mongoc_server_description_t *sd,
          mongoc_server_description_set_topology_version (
             sd, &incoming_topology_version);
          bson_destroy (&incoming_topology_version);
+      } else if (strcmp ("serviceId", bson_iter_key (&iter)) == 0) {
+          if (!BSON_ITER_HOLDS_OID (&iter))
+            goto failure;
+         bson_oid_copy_unsafe (bson_iter_oid (&iter), &sd->service_id);
       }
-      // LBTODO: process serviceID
    }
 
    if (is_shard) {
@@ -799,6 +803,7 @@ mongoc_server_description_new_copy (
    bson_init (&copy->tags);
    bson_init (&copy->compressors);
    bson_copy_to (&description->topology_version, &copy->topology_version);
+   bson_oid_copy (&description->service_id, &copy->service_id);
 
    if (description->has_hello_response) {
       /* calls mongoc_server_description_reset */
@@ -1243,7 +1248,11 @@ mongoc_server_description_set_topology_version (mongoc_server_description_t *sd,
 
 bool
 mongoc_server_description_service_id (const mongoc_server_description_t *description, bson_oid_t *oid) {
-   // LBTODO
-   memset (oid, 0, sizeof (bson_oid_t));
-   return false;
+   bson_oid_copy (&description->service_id, oid);
+
+   if (0 == bson_oid_compare (oid, &kObjectIdZero)) {
+      /* serviceID is unset. */
+      return false;
+   }
+   return true;
 }

src/libmongoc/src/mongoc/mongoc-server-description.h

@@ -66,10 +66,6 @@ MONGOC_EXPORT (int32_t)
 mongoc_server_description_compressor_id (
    const mongoc_server_description_t *description);
 
-// LBTODO
-MONGOC_EXPORT (bool)
-mongoc_server_description_service_id (const mongoc_server_description_t *description, bson_oid_t *oid);
-
 BSON_END_DECLS
 
 #endif

src/libmongoc/src/mongoc/mongoc-topology-scanner-private.h

@@ -83,7 +83,6 @@ typedef struct mongoc_topology_scanner_node {
    /* handshake_sd is a server description constructed from the response of the
     * initial handshake. It is bound to the lifetime of stream. */
    mongoc_server_description_t *handshake_sd;
-   bool loadbalanced;
 } mongoc_topology_scanner_node_t;
 
 typedef struct mongoc_topology_scanner {
@@ -119,6 +118,7 @@ typedef struct mongoc_topology_scanner {
    bool speculative_authentication;
 
    mongoc_server_api_t *api;
+   bool loadbalanced;
 } mongoc_topology_scanner_t;
 
 mongoc_topology_scanner_t *

src/libmongoc/src/mongoc/mongoc-topology-scanner.c

@@ -260,8 +260,6 @@ _build_handshake_cmd (mongoc_topology_scanner_t *ts)
    bson_destroy (doc);
    bson_copy_to (ts->api ? &ts->hello_cmd : &ts->legacy_hello_cmd, doc);
 
-   // LBTODO: if ts->loadbalanced, append loadBalanced: true
-
    BSON_APPEND_DOCUMENT_BEGIN (doc, HANDSHAKE_FIELD, &subdoc);
    res = _mongoc_handshake_build_doc_with_application (&subdoc, ts->appname);
    bson_append_document_end (doc, &subdoc);
@@ -280,6 +278,10 @@ _build_handshake_cmd (mongoc_topology_scanner_t *ts)
    }
    bson_append_array_end (doc, &subdoc);
 
+   if (ts->loadbalanced) {
+      BSON_APPEND_BOOL (doc, "loadBalanced", true);
+   }
+
    /* Return whether the handshake doc fit the size limit */
    return res;
 }
@@ -1402,4 +1404,4 @@ void
 _mongoc_topology_scanner_set_loadbalanced (mongoc_topology_scanner_t *ts, bool val) {
    BSON_ASSERT (bson_empty (&ts->handshake_cmd));
    ts->loadbalanced = true;
-}
+}

src/libmongoc/tests/test-mongoc-loadbalanced.c

@@ -443,10 +443,10 @@ test_loadbalanced_cooldown_is_bypassed_single (void *unused)
 
 /* Tests:
  * - loadBalanced: true is added to the handshake
- * - serviceID is set in the server description.
+ * - serviceId is set in the server description.
  */
 #define LB_HELLO                                                               \
-   "{'ismaster': true, 'maxWireVersion': 13, 'msg': 'isdbgrid', 'serviceID', " \
+   "{'ismaster': true, 'maxWireVersion': 13, 'msg': 'isdbgrid', 'serviceId': " \
    "{'$oid': 'AAAAAAAAAAAAAAAAAAAAAAAA'}}"
 static void
 test_loadbalanced_handshake_sends_loadbalanced (void)
@@ -464,6 +464,7 @@ test_loadbalanced_handshake_sends_loadbalanced (void)
 
    server = mock_server_new ();
    mock_server_run (server);
+   mock_server_auto_endsessions (server);
    uri = mongoc_uri_copy (mock_server_get_uri (server));
    mongoc_uri_set_option_as_bool (uri, MONGOC_URI_LOADBALANCED, true);
    client = mongoc_client_new_from_uri (uri);
@@ -519,6 +520,7 @@ test_loadbalanced_handshake_rejects_non_loadbalanced (void)
 
    server = mock_server_new ();
    mock_server_run (server);
+   mock_server_auto_endsessions (server);
    uri = mongoc_uri_copy (mock_server_get_uri (server));
    mongoc_uri_set_option_as_bool (uri, MONGOC_URI_LOADBALANCED, true);
    client = mongoc_client_new_from_uri (uri);
@@ -538,7 +540,7 @@ test_loadbalanced_handshake_rejects_non_loadbalanced (void)
 
    ASSERT_ERROR_CONTAINS (error,
                           MONGOC_ERROR_CLIENT,
-                          123,
+                          MONGOC_ERROR_CLIENT_INVALID_LOAD_BALANCER,
                           "Driver attempted to initialize in load balancing "
                           "mode, but the server does not support this mode");