Make it possible to siphon out a single MJPEG stream.

[nageru] / shared / httpd.cpp

diff --git a/shared/httpd.cpp b/shared/httpd.cpp
index 5442e7f123f7533b9740fc244241acd9123b1703..a881919cace1abd5e2399a192f60416f39ac6dc7 100644 (file)
--- a/shared/httpd.cpp
+++ b/shared/httpd.cpp
@@ -27,6 +27,11 @@ HTTPD::HTTPD()
 {
        global_metrics.add("num_connected_clients", &metric_num_connected_clients, Metrics::TYPE_GAUGE);
        global_metrics.add("num_connected_multicam_clients", &metric_num_connected_multicam_clients, Metrics::TYPE_GAUGE);
+       for (unsigned stream_idx = 0; stream_idx < MAX_VIDEO_CARDS; ++stream_idx) {
+               global_metrics.add("num_connected_siphon_clients",
+                       {{ "card", to_string(stream_idx) }},
+                       &metric_num_connected_siphon_clients[stream_idx], Metrics::TYPE_GAUGE);
+       }
 }
 
 HTTPD::~HTTPD()
@@ -59,12 +64,24 @@ void HTTPD::stop()
        }
 }
 
-void HTTPD::add_data(StreamType stream_type, const char *buf, size_t size, bool keyframe, int64_t time, AVRational timebase)
+void HTTPD::set_header(StreamID stream_id, const string &data)
 {
        lock_guard<mutex> lock(streams_mutex);
+       header[stream_id] = data;
+       add_data_locked(stream_id, data.data(), data.size(), Stream::DATA_TYPE_HEADER, AV_NOPTS_VALUE, AVRational{ 1, 0 });
+}
+
+void HTTPD::add_data(StreamID stream_id, const char *buf, size_t size, bool keyframe, int64_t time, AVRational timebase)
+{
+       lock_guard<mutex> lock(streams_mutex);
+       add_data_locked(stream_id, buf, size, keyframe ? Stream::DATA_TYPE_KEYFRAME : Stream::DATA_TYPE_OTHER, time, timebase);
+}
+
+void HTTPD::add_data_locked(StreamID stream_id, const char *buf, size_t size, Stream::DataType data_type, int64_t time, AVRational timebase)
+{
        for (Stream *stream : streams) {
-               if (stream->get_stream_type() == stream_type) {
-                       stream->add_data(buf, size, keyframe ? Stream::DATA_TYPE_KEYFRAME : Stream::DATA_TYPE_OTHER, time, timebase);
+               if (stream->get_stream_id() == stream_id) {
+                       stream->add_data(buf, size, data_type, time, timebase);
                }
        }
 }
@@ -90,11 +107,16 @@ int HTTPD::answer_to_connection(MHD_Connection *connection,
        } else {
                framing = HTTPD::Stream::FRAMING_RAW;
        }
-       HTTPD::StreamType stream_type;
+       HTTPD::StreamID stream_id;
        if (strcmp(url, "/multicam.mp4") == 0) {
-               stream_type = HTTPD::StreamType::MULTICAM_STREAM;
+               stream_id.type = HTTPD::StreamType::MULTICAM_STREAM;
+               stream_id.index = 0;
+       } else if (strncmp(url, "/feeds/", 7) == 0) {
+               stream_id.type = HTTPD::StreamType::SIPHON_STREAM;
+               stream_id.index = atoi(url + 7);
        } else {
-               stream_type = HTTPD::StreamType::MAIN_STREAM;
+               stream_id.type = HTTPD::StreamType::MAIN_STREAM;
+               stream_id.index = 0;
        }
 
        if (strcmp(url, "/metrics") == 0) {
@@ -130,16 +152,20 @@ int HTTPD::answer_to_connection(MHD_Connection *connection,
                return ret;
        }
 
-       HTTPD::Stream *stream = new HTTPD::Stream(this, framing, stream_type);
-       stream->add_data(header[stream_type].data(), header[stream_type].size(), Stream::DATA_TYPE_HEADER, AV_NOPTS_VALUE, AVRational{ 1, 0 });
+       HTTPD::Stream *stream = new HTTPD::Stream(this, framing, stream_id);
+       const string &hdr = header[stream_id];
+       stream->add_data(hdr.data(), hdr.size(), Stream::DATA_TYPE_HEADER, AV_NOPTS_VALUE, AVRational{ 1, 0 });
        {
                lock_guard<mutex> lock(streams_mutex);
                streams.insert(stream);
        }
        ++metric_num_connected_clients;
-       if (stream_type == HTTPD::StreamType::MULTICAM_STREAM) {
+       if (stream_id.type == HTTPD::StreamType::MULTICAM_STREAM) {
                ++metric_num_connected_multicam_clients;
        }
+       if (stream_id.type == HTTPD::StreamType::SIPHON_STREAM) {
+               ++metric_num_connected_siphon_clients[stream_id.index];
+       }
        *con_cls = stream;
 
        // Does not strictly have to be equal to MUX_BUFFER_SIZE.
@@ -160,9 +186,12 @@ void HTTPD::free_stream(void *cls)
 {
        HTTPD::Stream *stream = (HTTPD::Stream *)cls;
        HTTPD *httpd = stream->get_parent();
-       if (stream->get_stream_type() == HTTPD::StreamType::MULTICAM_STREAM) {
+       if (stream->get_stream_id().type == HTTPD::StreamType::MULTICAM_STREAM) {
                --httpd->metric_num_connected_multicam_clients;
        }
+       if (stream->get_stream_id().type == HTTPD::StreamType::SIPHON_STREAM) {
+               --httpd->metric_num_connected_siphon_clients[stream->get_stream_id().index];
+       }
        {
                lock_guard<mutex> lock(httpd->streams_mutex);
                delete stream;
@@ -182,7 +211,7 @@ ssize_t HTTPD::Stream::reader_callback(uint64_t pos, char *buf, size_t max)
        unique_lock<mutex> lock(buffer_mutex);
        has_buffered_data.wait(lock, [this] { return should_quit || !buffered_data.empty(); });
        if (should_quit) {
-               return 0;
+               return -1;
        }
 
        ssize_t ret = 0;
@@ -196,6 +225,7 @@ ssize_t HTTPD::Stream::reader_callback(uint64_t pos, char *buf, size_t max)
                        buf += len;
                        ret += len;
                        max -= len;
+                       buffered_data_bytes -= s.size();
                        buffered_data.pop_front();
                        used_of_buffered_data = 0;
                } else {
@@ -213,7 +243,7 @@ ssize_t HTTPD::Stream::reader_callback(uint64_t pos, char *buf, size_t max)
 
 void HTTPD::Stream::add_data(const char *buf, size_t buf_size, HTTPD::Stream::DataType data_type, int64_t time, AVRational timebase)
 {
-       if (buf_size == 0) {
+       if (buf_size == 0 || should_quit) {
                return;
        }
        if (data_type == DATA_TYPE_KEYFRAME) {
@@ -225,6 +255,17 @@ void HTTPD::Stream::add_data(const char *buf, size_t buf_size, HTTPD::Stream::Da
 
        lock_guard<mutex> lock(buffer_mutex);
 
+       if (buffered_data_bytes + buf_size > (1ULL << 30)) {
+               // More than 1GB of backlog; the client obviously isn't keeping up,
+               // so kill it instead of going out of memory. Note that this
+               // won't kill the client immediately, but will cause the next callback
+               // to kill the client.
+               should_quit = true;
+               buffered_data.clear();
+               has_buffered_data.notify_all();
+               return;
+       }
+
        if (framing == FRAMING_METACUBE) {
                int flags = 0;
                if (data_type == DATA_TYPE_HEADER) {
@@ -249,6 +290,7 @@ void HTTPD::Stream::add_data(const char *buf, size_t buf_size, HTTPD::Stream::Da
                        hdr.csum = htons(metacube2_compute_crc(&hdr));
                        buffered_data.emplace_back((char *)&hdr, sizeof(hdr));
                        buffered_data.emplace_back((char *)&packet, sizeof(packet));
+                       buffered_data_bytes += sizeof(hdr) + sizeof(packet);
                }
 
                metacube2_block_header hdr;
@@ -257,8 +299,10 @@ void HTTPD::Stream::add_data(const char *buf, size_t buf_size, HTTPD::Stream::Da
                hdr.flags = htons(flags);
                hdr.csum = htons(metacube2_compute_crc(&hdr));
                buffered_data.emplace_back((char *)&hdr, sizeof(hdr));
+               buffered_data_bytes += sizeof(hdr);
        }
        buffered_data.emplace_back(buf, buf_size);
+       buffered_data_bytes += buf_size;
 
        // Send a Metacube2 timestamp every keyframe.
        if (framing == FRAMING_METACUBE && data_type == DATA_TYPE_KEYFRAME) {
@@ -277,6 +321,7 @@ void HTTPD::Stream::add_data(const char *buf, size_t buf_size, HTTPD::Stream::Da
                hdr.csum = htons(metacube2_compute_crc(&hdr));
                buffered_data.emplace_back((char *)&hdr, sizeof(hdr));
                buffered_data.emplace_back((char *)&packet, sizeof(packet));
+               buffered_data_bytes += sizeof(hdr) + sizeof(packet);
        }
 
        has_buffered_data.notify_all();