From b0274b8254dfab5bfbea855d5127e75ba59e874e Mon Sep 17 00:00:00 2001
From: "Zed A. Shaw" <zed.shaw@gmail.com>
Date: Sun, 22 Sep 2024 17:03:06 -0400
Subject: [PATCH] Have the server back off when ffmpeg fails repeatedly.

---
 config.json |  2 +-
 main.cpp    | 27 +++++++++++++++++++++------
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/config.json b/config.json
index c6da316..941059f 100644
--- a/config.json
+++ b/config.json
@@ -1,5 +1,5 @@
 {
-  "listen_at": "rtmp://192.168.254.146/",
+  "listen_at": "rtmp://192.168.254.147/",
   "bitrate": "7M",
   "send_to": "https://127.0.0.1:5001/"
 }
diff --git a/main.cpp b/main.cpp
index abfc11b..5a37742 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,13 +1,17 @@
 #define FSM_DEBUG 1
 #include <fmt/core.h>
+#include <fmt/chrono.h>
 #include <nlohmann/json.hpp>
 #include <fstream>
+#include <chrono>
+#include <thread>
 #include "dbc.hpp"
 #include "fsm.hpp"
 
 #define BUF_MAX 1024 * 10
 using namespace fmt;
 using namespace nlohmann;
+using namespace std::chrono_literals;
 
 struct Config {
   json json_config;
@@ -30,7 +34,7 @@ struct Config {
 };
 
 FILE *run_ffmpeg(Config &config) {
-  string ffmpeg_cmd = format("ffmpeg -listen 1 -i {} -bufsize 3000k  -maxrate {} -flags +global_header  -c:v libx264  -preset veryfast -tune zerolatency  -g:v 60  -vb {} -c:a copy -f flv {}",
+  string ffmpeg_cmd = format("ffmpeg -listen 1 -i {} -bufsize 3000k  -maxrate {} -flags +global_header  -c:v libx264  -preset veryfast -tune zerolatency  -g:v 60  -vb {} -c:a copy -f flv {} 2> output.log",
       config.listen_at,
       config.bitrate,
       config.bitrate,
@@ -38,7 +42,7 @@ FILE *run_ffmpeg(Config &config) {
 
   println("RUNNING: {}", ffmpeg_cmd);
 
-  return popen(ffmpeg_cmd.c_str(), "r");
+  return popen(ffmpeg_cmd.c_str(), "re");
 }
 
 
@@ -55,13 +59,14 @@ class Server : DeadSimpleFSM<ServerState, ServerEvent> {
   FILE *handle = nullptr;
   char buffer[BUF_MAX];
   char *res = nullptr;
+  std::chrono::milliseconds wait_time = 200ms;
 
 public:
 
   Server(Config &config) : config(config) {};
 
   bool stopped() {
-    return in_state(ServerState::STOP) || in_state(ServerState::ERROR);
+    return in_state(ServerState::STOP);
   }
 
   void event(ServerEvent ev) {
@@ -76,8 +81,10 @@ public:
   void START(ServerEvent ev) {
     handle = run_ffmpeg(config);
     if(handle == nullptr) {
+      dbc::log("ERROR when launching ffmpeg");
       state(ServerState::ERROR);
     } else {
+      wait_time = 200ms;
       state(ServerState::READING);
     }
   }
@@ -86,6 +93,7 @@ public:
     res = fgets(buffer, BUF_MAX, handle);
 
     if(res == nullptr) {
+      dbc::log("STOP shutting down...");
       state(ServerState::STOP);
     } else {
       state(ServerState::READING);
@@ -95,6 +103,7 @@ public:
   void 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);
@@ -102,12 +111,18 @@ public:
   }
 
   void ERROR(ServerEvent ev) {
-    state(ServerState::ERROR);
+    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);
   }
 };
 
-int main() {
-  Config config("config.json");
+int main(int argc, char *argv[]) {
+  dbc::check(argc == 2, "USAGE: distributary config.json");
+  println("Using config {}", argv[1]);
+  Config config(argv[1]);
   Server server(config);
 
   while(!server.stopped()) {