distributary/server.cpp

#include "server.hpp"
#include <nlohmann/json.hpp>
#include <fmt/core.h>
#include <fmt/chrono.h>
#include <thread>
#include "dbc.hpp"

using namespace fmt;

FILE *run_ffmpeg(Config &config) {
  string ffmpeg_cmd = format("ffmpeg -listen 1 -i {} -bufsize 3000k",
      config.listen_at);

  for(auto &el : config.send_to) {
    SendTo send_spec = el.second;
    ffmpeg_cmd += format(" -maxrate {} -flags +global_header -c:v libx264 -preset veryfast -tune zerolatency  -g:v 60 -vb {} -c:a copy -f flv {}",
      send_spec.bitrate, send_spec.bitrate, send_spec.url);
  }

  println("RUNNING: {}", ffmpeg_cmd);

  return popen(ffmpeg_cmd.c_str(), "re");
}

bool Server::stopped() {
  return in_state(ServerState::STOP);
}

void Server::event(ServerEvent ev) {
  switch(_state) {
    FSM_STATE(ServerState, START, ev);
    FSM_STATE(ServerState, READING, ev);
    FSM_STATE(ServerState, STOP, ev);
    FSM_STATE(ServerState, ERROR, ev);
  }
}

void Server::START(ServerEvent ev) {
  handle = run_ffmpeg(config);
  if(handle == nullptr) {
    dbc::log("ERROR when launching ffmpeg");
    state(ServerState::ERROR);
  } else {
    wait_time = 200ms;
    fail_count = 0;
    state(ServerState::READING);
  }
}

void Server::READING(ServerEvent ev) {
  res = fgets(buffer, BUF_MAX, handle);

  if(res == nullptr) {
    dbc::log("STOP shutting down...");
    state(ServerState::STOP);
  } else {
    state(ServerState::READING);
  }
}

void Server::STOP(ServerEvent ev) {
  int rc = pclose(handle);
  if(rc != 0) {
    dbc::log("ERROR when calling pclose on ffmpeg");
    state(ServerState::ERROR);
  } else {
    state(ServerState::STOP);
  }
}

void Server::ERROR(ServerEvent ev) {
  fail_count++;
  if(fail_count < config.fail_max) {
    println("Error in server, waiting {}...", wait_time);
    wait_time *= 2;
    std::this_thread::sleep_for(wait_time);
    dbc::log("Attempting to run it again...");
    state(ServerState::START);
  } else {
    dbc::log("ffmpeg failed to many times, exiting.");
    state(ServerState::STOP);
  }
}