add web service for status

meson.build

@@ -71,7 +71,7 @@ doctest_dep=dependency('doctest')
 simplesockets_dep = dependency('simplesockets', static: true)
 # argparse_dep = dependency('argparse', version: '>=3')
 
-executable('simplomon', 'simplomon.cc', 'notifiers.cc', 'minicurl.cc', 'dnsmon.cc', 'record-types.cc', 'dnsmessages.cc', 'dns-storage.cc', 'netmon.cc', 'luabridge.cc',
+executable('simplomon', 'simplomon.cc', 'notifiers.cc', 'minicurl.cc', 'dnsmon.cc', 'record-types.cc', 'dnsmessages.cc', 'dns-storage.cc', 'netmon.cc', 'luabridge.cc', 'webservice.cc',
 	dependencies: [json_dep, fmt_dep, cpphttplib, 
 	simplesockets_dep, lua_dep, curl_dep])
 

simplomon.cc

@@ -91,6 +91,8 @@ try
     fmt::print("Did not configure a notifier, can't notify anything\n");
   }
 
+  startWebService();
+
   CheckResultFilter crf;
   auto prevFiltered = crf.getFilteredResults(); // should be none
   for(;;) {

simplomon.hh

@@ -173,3 +173,4 @@ void checkLuaTable(sol::table data,
                    const std::set<std::string>& mandatory,
                    const std::set<std::string>& opt = std::set<std::string>());
 
+void startWebService();

webservice.cc

@@ -0,0 +1,35 @@
+#include "simplomon.hh"
+#include <nlohmann/json.hpp>
+#include "httplib.h"
+
+
+static void webserverThread(std::unique_ptr<httplib::Server> svr)
+{
+  if(svr->listen("0.0.0.0", 8080)) {
+    cout<<"Error launching server: "<<strerror(errno)<<endl;
+    exit(EXIT_FAILURE);
+  }
+}
+
+void startWebService()
+{
+  auto svr = make_unique<httplib::Server>();
+
+  svr->set_socket_options([](socket_t sock) {
+    int yes = 1;
+    setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
+               reinterpret_cast<const void *>(&yes), sizeof(yes));
+  });
+
+  svr->Get("/health", [](const httplib::Request &, httplib::Response &res) {
+    nlohmann::json j;
+    j["health"]="ok";
+    res.set_content(j.dump(), "application/json");
+  });
+
+  std::thread t(webserverThread, std::move(svr));
+  t.detach();
+
+
+}
+