set a home directory for stats output

tcp-proxy/Makefile

@@ -1,9 +1,10 @@
 CXX=$(shell which clang++ g++ c++ 2>/dev/null | head -n 1)
 
-INCLUDES?=-isystem ../ext/prometheus-cpp-lite-1.0/core/include  -isystem ../ext/prometheus-cpp-lite-1.0/simpleapi/include
+INCLUDES?=-isystem ../ext/prometheus-cpp-lite-1.0/core/include  -isystem ../ext/prometheus-cpp-lite-1.0/simpleapi/include -isystem ../ext/
 
 OBJS=Metrics.o	\
-	../node/Metrics.o 
+	../node/Metrics.o \
+	../osdep/OSUtils.o
 
 CXXFLAGS=-O3 -fno-rtti $(INCLUDES) -std=c++17 -pthread -frtti
 

tcp-proxy/tcp-proxy.cpp

@@ -42,12 +42,15 @@
 #include <vector>
 
 #include "../osdep/Phy.hpp"
+#include "../osdep/OSUtils.hpp"
 
 #include "Metrics.hpp"
 
 #define ZT_TCP_PROXY_CONNECTION_TIMEOUT_SECONDS 300
 #define ZT_TCP_PROXY_TCP_PORT 443
 
+#define HOMEDIR "/var/lib/zt-tcp-proxy"
+
 using namespace ZeroTier;
 
 /*
@@ -300,6 +303,17 @@ int main(int argc,char **argv)
 	signal(SIGHUP,SIG_IGN);
 	srand(time((time_t *)0));
 
+	if (!OSUtils::fileExists(HOMEDIR)) {
+		if (!OSUtils::mkdir(HOMEDIR)) {
+			fprintf(stderr,"%s: fatal error: unable to create %s\n",argv[0],HOMEDIR);
+			return 1;
+		}
+	}
+
+	prometheus::simpleapi::saver.set_registry(prometheus::simpleapi::registry_ptr);
+	prometheus::simpleapi::saver.set_delay(std::chrono::seconds(5));
+	prometheus::simpleapi::saver.set_out_file(HOMEDIR "/metrics.json");
+
 	TcpProxyService svc;
 	Phy<TcpProxyService *> phy(&svc,false,true);
 	svc.phy = &phy;