WEBRTC for communication between agents and browsers (#14874)

* initial webrtc setup

* missing files

* rewrite of webrtc integration

* initialization and cleanup of webrtc connections

* make it compile without libdatachannel

* add missing webrtc_initialize() function when webrtc is not enabled

* make c++17 optional

* add build/m4/ax_compiler_vendor.m4

* add ax_cxx_compile_stdcxx.m4

* added new m4 files to makefile.am

* id all webrtc connections

* show warning when webrtc is disabled

* fixed message

* moved all webrtc error checking inside webrtc.cpp

* working webrtc connection establishment and cleanup

* remove obsolete code

* rewrote webrtc code in C to remove dependency for c++17

* fixed left-over reference

* detect binary and text messages

* minor fix

* naming of webrtc threads

* added webrtc configuration

* fix for thread_get_name_np()

* smaller web_client memory footprint

* universal web clients cache

* free web clients every 100 uses

* webrtc is now enabled by default only when compiled with internal checks

* webrtc responses to /api/ requests, including LZ4 compression

* fix for binary and text messages

* web_client_cache is now global

* unification of the internal web server API, for web requests, aclk request, webrtc requests

* more cleanup and unification of web client timings

* fixed compiler warnings

* update sent and received bytes

* eliminated of almost all big buffers in web client

* registry now uses the new json generation

* cookies are now an array; fixed redirects

* fix redirects, again

* write cookies directly to the header buffer, eliminating the need for cookie structures in web client

* reset the has_cookies flag

* gathered all web client cleanup to one function

* fixes redirects

* added summary.globals in /api/v2/data response

* ars to arc in /api/v2/data

* properly handle host impersonation

* set the context of mem.numa_nodes

2 files changed, 16 insertions, 0 deletions

diff --git a/daemon/common.h b/daemon/common.h
index 428ce1cdec..66ffd4a749 100644
--- a/daemon/common.h
+++ b/daemon/common.h
@@ -59,6 +59,7 @@
 
 // the netdata API
 #include "web/server/web_client.h"
+#include "web/rtc/webrtc.h"
 
 // all data collection plugins
 #include "collectors/all.h"
diff --git a/daemon/main.c b/daemon/main.c
index 0ef8f5735e..606de128bd 100644
--- a/daemon/main.c
+++ b/daemon/main.c
@@ -309,6 +309,8 @@ static bool service_wait_exit(SERVICE_TYPE service, usec_t timeout_ut) {
         timeout = false;                                \
     }
 
+void web_client_cache_destroy(void);
+
 void netdata_cleanup_and_exit(int ret) {
     usec_t started_ut = now_monotonic_usec();
     usec_t last_ut = started_ut;
@@ -336,6 +338,10 @@ void netdata_cleanup_and_exit(int ret) {
     }
 #endif
 
+    delta_shutdown_time("close webrtc connections");
+
+    webrtc_close_all_connections();
+
     delta_shutdown_time("disable ML detection and training threads");
 
     ml_stop_threads();
@@ -380,6 +386,10 @@ void netdata_cleanup_and_exit(int ret) {
             SERVICE_MAINTENANCE
             , 3 * USEC_PER_SEC);
 
+    delta_shutdown_time("clear web client cache");
+
+    web_client_cache_destroy();
+
     delta_shutdown_time("clean rrdhost database");
 
     rrdhost_cleanup_all();
@@ -2137,6 +2147,11 @@ int main(int argc, char **argv) {
 #endif
 
     // ------------------------------------------------------------------------
+    // initialize WebRTC
+
+    webrtc_initialize();
+
+    // ------------------------------------------------------------------------
     // unblock signals
 
     signals_unblock();