Add stats sender to UNIX datagram socket

1 files changed, 123 insertions, 0 deletions

diff --git a/src/StatsPublish.cpp b/src/StatsPublish.cpp
new file mode 100644
index 0000000..ccf2bb4
--- /dev/null
+++ b/src/StatsPublish.cpp
@@ -0,0 +1,123 @@
+/* ------------------------------------------------------------------
+ * Copyright (C) 2019 Matthias P. Braendli
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ * -------------------------------------------------------------------
+ */
+
+#include "config.h"
+#include "StatsPublish.h"
+#include <stdexcept>
+#include <sstream>
+#include <cstring>
+#include <cerrno>
+#include <cassert>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+using namespace std;
+
+StatsPublisher::StatsPublisher(const string& socket_path) :
+    m_socket_path(socket_path)
+{
+    // The client socket binds to a socket whose name depends on PID, and connects to
+    // `socket_path`
+
+    m_sock = socket(AF_UNIX, SOCK_DGRAM | SOCK_NONBLOCK, 0);
+    if (m_sock == -1) {
+        throw runtime_error("Stats socket creation failed: " + string(strerror(errno)));
+    }
+
+    struct sockaddr_un claddr;
+    memset(&claddr, 0, sizeof(struct sockaddr_un));
+    claddr.sun_family = AF_UNIX;
+    snprintf(claddr.sun_path, sizeof(claddr.sun_path), "/tmp/odr-audioenc.%ld", (long) getpid());
+
+    int ret = bind(m_sock, (const struct sockaddr *) &claddr, sizeof(struct sockaddr_un));
+    if (ret == -1) {
+        throw runtime_error("Stats socket bind failed " + string(strerror(errno)));
+    }
+}
+
+void StatsPublisher::update_audio_levels(int16_t audiolevel_left, int16_t audiolevel_right)
+{
+    m_audio_left = audiolevel_left;
+    m_audio_right = audiolevel_right;
+}
+
+void StatsPublisher::notify_underrun()
+{
+    m_num_underruns++;
+}
+
+void StatsPublisher::notify_overrun()
+{
+    m_num_overruns++;
+}
+
+void StatsPublisher::send_stats()
+{
+    // Manually build YAML, as it's quite easy.
+    stringstream yaml;
+    yaml << "---\n";
+    yaml << "program: " << PACKAGE_NAME << "\n";
+    yaml << "version: " <<
+#if defined(GITVERSION)
+            GITVERSION
+#else
+            PACKAGE_VERSION
+#endif
+            << "\n";
+    yaml << "audiolevels: { left: " << m_audio_left << ", right: " << m_audio_right << "}\n";
+    yaml << "driftcompensation: { underruns: " << m_num_underruns << ", overruns: " << m_num_overruns << "}\n";
+
+    const auto yamlstr = yaml.str();
+
+    struct sockaddr_un claddr;
+    memset(&claddr, 0, sizeof(struct sockaddr_un));
+    claddr.sun_family = AF_UNIX;
+    snprintf(claddr.sun_path, sizeof(claddr.sun_path), "%s", m_socket_path.c_str());
+
+    int ret = sendto(m_sock, yamlstr.data(), yamlstr.size(), 0,
+            (struct sockaddr *) &claddr, sizeof(struct sockaddr_un));
+    if (ret == -1) {
+        // This suppresses the -Wlogical-op warning
+        if (errno == EAGAIN
+#if EAGAIN != EWOULDBLOCK
+                or errno == EWOULDBLOCK
+#endif
+                or errno == ECONNREFUSED
+                or errno == ENOENT) {
+            if (m_destination_available) {
+                fprintf(stderr, "Stats destination not available at %s\n", m_socket_path.c_str());
+                m_destination_available = false;
+            }
+        }
+        else {
+            fprintf(stderr, "Statistics send failed: %s\n", strerror(errno));
+        }
+    }
+    else if (ret != yamlstr.size()) {
+        fprintf(stderr, "Statistics send incorrect length: %d bytes of %zu transmitted\n",
+                ret, yamlstr.size());
+    }
+    else if (not m_destination_available) {
+        fprintf(stderr, "Stats destination is now available at %s\n", m_socket_path.c_str());
+        m_destination_available = true;
+    }
+
+    m_audio_left = 0;
+    m_audio_right = 0;
+}