webrtc: Show provide status about the RTCPeerConnection via the REST API

Signed-off-by: Steffen Vogel <steffen.vogel@opal-rt.com>

include/villas/node.hpp

@@ -106,6 +106,12 @@ protected:
 		return -1;
 	}
 
+	virtual
+	json_t * _readStatus() const
+	{
+		return nullptr;
+	}
+
 public:
 	/** Initialize node with default values */
 	Node(const uuid_t &id = {}, const std::string &name = "");

include/villas/nodes/webrtc.hpp

@@ -47,6 +47,9 @@ protected:
 	virtual
 	int _write(struct Sample *smps[], unsigned cnt);
 
+	virtual
+	json_t * _readStatus() const;
+
 public:
 	WebRTCNode(const uuid_t &id = {}, const std::string &name = "");
 

include/villas/nodes/webrtc/peer_connection.hpp

@@ -10,6 +10,7 @@
 
 #pragma once
 
+#include <jansson.h>
 #include <rtc/rtc.hpp>
 
 #include <villas/log.hpp>
@@ -31,6 +32,8 @@ public:
 	void onMessage(std::function<void(rtc::binary)> callback);
 	void sendMessage(rtc::binary msg);
 
+	json_t * readStatus() const;
+
 	void connect();
 	void disconnect();
 

lib/node.cpp

@@ -463,6 +463,10 @@ json_t * Node::toJson() const
 	if (stats)
 		json_object_set_new(json_node, "stats", stats->toJson());
 
+	auto *status = _readStatus();
+	if (status)
+		json_object_set_new(json_node, "status", status);
+
 	/* Add all additional fields of node here.
 	 * This can be used for metadata */
 	json_object_update(json_node, config);

lib/nodes/webrtc/peer_connection.cpp

@@ -10,9 +10,11 @@
 
 #include <chrono>
 #include <thread>
+
 #include <fmt/core.h>
 #include <fmt/ostream.h>
 #include <fmt/chrono.h>
+
 #include <villas/utils.hpp>
 #include <villas/exceptions.hpp>
 #include <villas/nodes/webrtc/peer_connection.hpp>
@@ -79,6 +81,31 @@ bool PeerConnection::waitForDataChannel(std::chrono::seconds timeout)
 	return startupCondition.wait_until(lock, deadline, [this](){ return this->stopStartup; });
 }
 
+json_t * PeerConnection::readStatus()
+{
+	auto *json = json_pack("{ s: I, s: I }",
+		"bytes_received", conn->bytesReceived(),
+		"bytes_sent", conn->bytesSent()
+	);
+
+	auto rtt = conn->rtt();
+	if (rtt.has_value()) {
+		auto *json_rtt = json_real(rtt.value().count() / 1e3);
+		json_object_set_new(json, "rtt", json_rtt);
+	}
+
+	rtc::Candidate local, remote;
+	if (conn->getSelectedCandidatePair(&local, &remote)) {
+		auto *json_cp = json_pack("{ s: s, s: s }",
+			"local", std::string(local).c_str(),
+			"remote", std::string(remote).c_str()
+		);
+		json_object_set_new(json, "candidate_pair", json_cp);
+	}
+
+	return json;
+}
+
 void PeerConnection::notifyStartup()
 {
 	stopStartup = true;