Fix: handle new streams in live mode in relayd
authorJulien Desfossez <jdesfossez@efficios.com>
Wed, 15 Jan 2014 15:32:44 +0000 (10:32 -0500)
committerDavid Goulet <dgoulet@efficios.com>
Fri, 7 Feb 2014 20:27:33 +0000 (15:27 -0500)
Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
src/bin/lttng-relayd/live.c
src/bin/lttng-relayd/lttng-relayd.h
src/bin/lttng-relayd/lttng-viewer.h
src/bin/lttng-relayd/main.c

index 1a691a849c11e972fee17059df4d5c7068846f01..69e2eb3b286c2f54cad19fefbdbe1e5f2bb93492 100644 (file)
@@ -852,6 +852,166 @@ error:
        return ret;
 }
 
+/*
+ * Send the viewer the list of current sessions.
+ */
+static
+int viewer_get_new_streams(struct relay_command *cmd,
+               struct lttng_ht *sessions_ht)
+{
+       int ret, send_streams = 0;
+       uint32_t nb_streams = 0;
+       struct lttng_viewer_new_streams_request request;
+       struct lttng_viewer_new_streams_response response;
+       struct lttng_viewer_stream send_stream;
+       struct relay_stream *stream;
+       struct relay_viewer_stream *viewer_stream;
+       struct lttng_ht_node_ulong *node;
+       struct lttng_ht_iter iter;
+       struct relay_session *session;
+
+       assert(cmd);
+       assert(sessions_ht);
+
+       DBG("Get new streams received");
+
+       if (cmd->version_check_done == 0) {
+               ERR("Trying to get streams before version check");
+               ret = -1;
+               goto end_no_session;
+       }
+
+       health_code_update();
+
+       ret = cmd->sock->ops->recvmsg(cmd->sock, &request, sizeof(request), 0);
+       if (ret < 0 || ret != sizeof(request)) {
+               if (ret == 0) {
+                       /* Orderly shutdown. Not necessary to print an error. */
+                       DBG("Socket %d did an orderly shutdown", cmd->sock->fd);
+               } else {
+                       ERR("Relay failed to receive the command parameters.");
+               }
+               ret = -1;
+               goto error;
+       }
+
+       health_code_update();
+
+       rcu_read_lock();
+       lttng_ht_lookup(sessions_ht,
+                       (void *)((unsigned long) be64toh(request.session_id)), &iter);
+       node = lttng_ht_iter_get_node_ulong(&iter);
+       if (node == NULL) {
+               DBG("Relay session %" PRIu64 " not found",
+                               be64toh(request.session_id));
+               response.status = htobe32(VIEWER_NEW_STREAMS_ERR);
+               goto send_reply;
+       }
+
+       session = caa_container_of(node, struct relay_session, session_n);
+       if (cmd->session_id == session->id) {
+               /* We confirmed the viewer is asking for the same session. */
+               send_streams = 1;
+               response.status = htobe32(VIEWER_NEW_STREAMS_OK);
+       } else {
+               send_streams = 0;
+               response.status = htobe32(VIEWER_NEW_STREAMS_ERR);
+               goto send_reply;
+       }
+
+       /*
+        * Fill the viewer_streams_ht to count the number of streams ready to be
+        * sent and avoid concurrency issues on the relay_streams_ht and don't rely
+        * on a total session stream count.
+        */
+       pthread_mutex_lock(&session->viewer_ready_lock);
+       cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, stream,
+                       stream_n.node) {
+               struct relay_viewer_stream *vstream;
+
+               health_code_update();
+
+               /*
+                * Don't send stream if no ctf_trace, wrong session or if the stream is
+                * not ready for the viewer.
+                */
+               if (stream->session != cmd->session ||
+                               !stream->ctf_trace || !stream->viewer_ready) {
+                       continue;
+               }
+
+               vstream = live_find_viewer_stream_by_id(stream->stream_handle);
+               if (!vstream) {
+                       ret = init_viewer_stream(stream, 0);
+                       if (ret < 0) {
+                               pthread_mutex_unlock(&session->viewer_ready_lock);
+                               goto end_unlock;
+                       }
+                       nb_streams++;
+               } else if (!vstream->sent_flag) {
+                       nb_streams++;
+               }
+       }
+       pthread_mutex_unlock(&session->viewer_ready_lock);
+
+       response.streams_count = htobe32(nb_streams);
+
+send_reply:
+       health_code_update();
+       ret = cmd->sock->ops->sendmsg(cmd->sock, &response, sizeof(response), 0);
+       if (ret < 0) {
+               ERR("Relay sending viewer attach response");
+               goto end_unlock;
+       }
+       health_code_update();
+
+       /*
+        * Unknown or empty session, just return gracefully, the viewer knows what
+        * is happening.
+        */
+       if (!send_streams || !nb_streams) {
+               ret = 0;
+               goto end_unlock;
+       }
+
+       /* We should only be there if we have a session to attach to. */
+       cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, viewer_stream,
+                       stream_n.node) {
+               health_code_update();
+
+               /* Don't send back if session does not match or already sent. */
+               if (viewer_stream->session_id != cmd->session->id ||
+                               viewer_stream->sent_flag) {
+                       continue;
+               }
+
+               send_stream.id = htobe64(viewer_stream->stream_handle);
+               send_stream.ctf_trace_id = htobe64(viewer_stream->ctf_trace->id);
+               send_stream.metadata_flag = htobe32(viewer_stream->metadata_flag);
+               strncpy(send_stream.path_name, viewer_stream->path_name,
+                               sizeof(send_stream.path_name));
+               strncpy(send_stream.channel_name, viewer_stream->channel_name,
+                               sizeof(send_stream.channel_name));
+
+               ret = cmd->sock->ops->sendmsg(cmd->sock, &send_stream,
+                               sizeof(send_stream), 0);
+               if (ret < 0) {
+                       ERR("Relay sending stream %" PRIu64, viewer_stream->stream_handle);
+                       goto end_unlock;
+               }
+               DBG("Sent stream %" PRIu64 " to viewer", viewer_stream->stream_handle);
+               viewer_stream->sent_flag = 1;
+       }
+
+       ret = 0;
+
+end_unlock:
+       rcu_read_unlock();
+end_no_session:
+error:
+       return ret;
+}
+
 /*
  * Send the viewer the list of current sessions.
  */
@@ -860,7 +1020,7 @@ int viewer_attach_session(struct relay_command *cmd,
                struct lttng_ht *sessions_ht)
 {
        int ret, send_streams = 0;
-       uint32_t nb_streams = 0, nb_streams_ready = 0;
+       uint32_t nb_streams = 0;
        struct lttng_viewer_attach_session_request request;
        struct lttng_viewer_attach_session_response response;
        struct lttng_viewer_stream send_stream;
@@ -954,6 +1114,7 @@ int viewer_attach_session(struct relay_command *cmd,
                 * ready to be sent and avoid concurrency issues on the
                 * relay_streams_ht and don't rely on a total session stream count.
                 */
+               pthread_mutex_lock(&session->viewer_ready_lock);
                cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, node, node) {
                        struct relay_viewer_stream *vstream;
 
@@ -967,7 +1128,6 @@ int viewer_attach_session(struct relay_command *cmd,
                        if (stream->session != cmd->session) {
                                continue;
                        }
-                       nb_streams++;
 
                        /*
                         * Don't send streams with no ctf_trace, they are not
@@ -976,21 +1136,19 @@ int viewer_attach_session(struct relay_command *cmd,
                        if (!stream->ctf_trace || !stream->viewer_ready) {
                                continue;
                        }
-                       nb_streams_ready++;
 
                        vstream = live_find_viewer_stream_by_id(stream->stream_handle);
                        if (!vstream) {
                                ret = init_viewer_stream(stream, seek_last);
                                if (ret < 0) {
+                                       pthread_mutex_unlock(&session->viewer_ready_lock);
                                        goto end_unlock;
                                }
                        }
+                       nb_streams++;
                }
+               pthread_mutex_unlock(&session->viewer_ready_lock);
 
-               /* We must have the same amount of existing stream and ready stream. */
-               if (nb_streams != nb_streams_ready) {
-                       nb_streams = 0;
-               }
                response.streams_count = htobe32(nb_streams);
        }
 
@@ -1042,6 +1200,7 @@ send_reply:
                        goto end_unlock;
                }
                DBG("Sent stream %" PRIu64 " to viewer", viewer_stream->stream_handle);
+               viewer_stream->sent_flag = 1;
        }
        ret = 0;
 
@@ -1719,6 +1878,9 @@ int process_control(struct lttng_viewer_cmd *recv_hdr,
        case VIEWER_GET_METADATA:
                ret = viewer_get_metadata(cmd);
                break;
+       case VIEWER_GET_NEW_STREAMS:
+               ret = viewer_get_new_streams(cmd, sessions_ht);
+               break;
        default:
                ERR("Received unknown viewer command (%u)", be32toh(recv_hdr->cmd));
                live_relay_unknown_command(cmd);
index ab1ccd410e06773686f2bf6f3aefcc9c15ccb362..b5e7c75fdd4b901140c9ec91088791cd1b9f599b 100644 (file)
@@ -88,6 +88,13 @@ struct relay_session {
         * viewer-side if new streams got added since the last check.
         */
        unsigned long new_streams;
+
+       /*
+        * Used to synchronize the process where we flag every streams readiness
+        * for the viewer when the streams_sent message is received and the viewer
+        * process of sending those streams.
+        */
+       pthread_mutex_t viewer_ready_lock;
 };
 
 /*
@@ -208,6 +215,8 @@ struct relay_viewer_stream {
         * it sets this flag to inform that it is a normal error.
         */
        unsigned int abort_flag:1;
+       /* Indicates if this stream has been sent to a viewer client. */
+       unsigned int sent_flag:1;
 };
 
 /*
index 1977a43b460852627bec6b8a6c1444e2da29ad83..baa8964bf78dc37236d24d0799c0111f6f80f032 100644 (file)
@@ -44,6 +44,7 @@ enum lttng_viewer_command {
        VIEWER_GET_NEXT_INDEX   = 4,
        VIEWER_GET_PACKET       = 5,
        VIEWER_GET_METADATA     = 6,
+       VIEWER_GET_NEW_STREAMS  = 7,
 };
 
 enum lttng_viewer_attach_return_code {
@@ -88,6 +89,12 @@ enum lttng_viewer_seek {
        VIEWER_SEEK_LAST        = 2,
 };
 
+enum lttng_viewer_new_streams_return_code {
+       VIEWER_NEW_STREAMS_OK           = 1, /* If new streams are being sent. */
+       VIEWER_NEW_STREAMS_NO_NEW       = 2, /* If no new streams are available. */
+       VIEWER_NEW_STREAMS_ERR          = 3, /* Error. */
+};
+
 struct lttng_viewer_session {
        uint64_t id;
        uint32_t live_timer;
@@ -198,4 +205,20 @@ struct lttng_viewer_metadata_packet {
        char data[];
 } __attribute__((__packed__));
 
+/*
+ * VIEWER_GET_NEW_STREAMS payload.
+ */
+struct lttng_viewer_new_streams_request {
+       uint64_t session_id;
+} __attribute__((__packed__));
+
+struct lttng_viewer_new_streams_response {
+       /* enum lttng_viewer_new_streams_return_code */
+       uint32_t status;
+       uint32_t streams_count;
+       /* struct lttng_viewer_stream */
+       char stream_list[];
+} __attribute__((__packed__));
+
+
 #endif /* LTTNG_VIEWER_H */
index 380b4f833042cad3dcf7809e1871016fda753506..730eaf203102886b206aa5d267afc2f8bc9e98b6 100644 (file)
@@ -1160,6 +1160,7 @@ int relay_create_session(struct lttcomm_relayd_hdr *recv_hdr,
        session->sock = cmd->sock;
        session->minor = cmd->minor;
        session->major = cmd->major;
+       pthread_mutex_init(&session->viewer_ready_lock, NULL);
        cmd->session = session;
 
        reply.session_id = htobe64(session->id);
@@ -1207,6 +1208,8 @@ void set_viewer_ready_flag(struct relay_command *cmd)
 {
        struct relay_stream_recv_handle *node, *tmp_node;
 
+       pthread_mutex_lock(&cmd->session->viewer_ready_lock);
+
        cds_list_for_each_entry_safe(node, tmp_node, &cmd->recv_head, node) {
                struct relay_stream *stream;
 
@@ -1229,6 +1232,7 @@ void set_viewer_ready_flag(struct relay_command *cmd)
                free(node);
        }
 
+       pthread_mutex_unlock(&cmd->session->viewer_ready_lock);
        return;
 }
 
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