[easylog]Support multiple instance (#178)

include/easylog/easylog.h

@@ -17,10 +17,12 @@
 #include "appender.hpp"
 
 namespace easylog {
+
+template <size_t Id = 0>
 class logger {
  public:
-  static logger &instance() {
+  static logger<Id> &instance() {
-    static logger instance;
+    static logger<Id> instance;
     return instance;
   }
 
@@ -110,44 +112,52 @@ class logger {
   appender *appender_ = nullptr;
 };
 
+template <size_t Id = 0>
 inline void init_log(Severity min_severity, const std::string &filename = "",
                      bool enable_console = true, size_t max_file_size = 0,
                      size_t max_files = 0, bool flush_every_time = false) {
-  logger::instance().init(min_severity, enable_console, filename, max_file_size,
+  logger<Id>::instance().init(min_severity, enable_console, filename,
-                          max_files, flush_every_time);
+                              max_file_size, max_files, flush_every_time);
 }
 
-inline void flush() { logger::instance().flush(); }
+template <size_t Id = 0>
+inline void flush() {
+  logger<Id>::instance().flush();
+}
 }  // namespace easylog
 
-#define ELOG_IMPL(severity)                                           \
+#define ELOG_IMPL(severity, Id, ...)                                  \
-  if (!easylog::logger::instance().check_severity(severity)) {        \
+  if (!easylog::logger<Id>::instance().check_severity(severity)) {    \
     ;                                                                 \
   }                                                                   \
   else                                                                \
-    easylog::logger::instance() +=                                    \
+    easylog::logger<Id>::instance() +=                                \
         easylog::record_t(std::chrono::system_clock::now(), severity, \
                           GET_STRING(__FILE__, __LINE__))             \
             .ref()
 
-#define ELOG(severity) ELOG_IMPL(Severity::severity)
+#define ELOG(severity, ...) ELOG_IMPL(Severity::severity, __VA_ARGS__, 0)
 
-#define ELOGV_IMPL(severity, fmt, ...)                                \
+#define ELOGV_IMPL(severity, Id, fmt, ...)                            \
-  if (!easylog::logger::instance().check_severity(severity)) {        \
+  if (!easylog::logger<Id>::instance().check_severity(severity)) {    \
     ;                                                                 \
   }                                                                   \
   else {                                                              \
-    easylog::logger::instance() +=                                    \
+    easylog::logger<Id>::instance() +=                                \
         easylog::record_t(std::chrono::system_clock::now(), severity, \
                           GET_STRING(__FILE__, __LINE__))             \
             .sprintf(fmt, __VA_ARGS__);                               \
     if (severity == Severity::CRITICAL) {                             \
-      easylog::flush();                                               \
+      easylog::flush<Id>();                                           \
       std::exit(EXIT_FAILURE);                                        \
     }                                                                 \
   }
 
-#define ELOGV(severity, ...) ELOGV_IMPL(Severity::severity, __VA_ARGS__, "\n")
+#define ELOGV(severity, ...) \
+  ELOGV_IMPL(Severity::severity, 0, __VA_ARGS__, "\n")
+
+#define MELOGV(severity, Id, ...) \
+  ELOGV_IMPL(Severity::severity, Id, __VA_ARGS__, "\n")
 
 #define ELOG_TRACE ELOG(INFO)
 #define ELOG_DEBUG ELOG(DEBUG)
@@ -156,9 +166,16 @@ inline void flush() { logger::instance().flush(); }
 #define ELOG_ERROR ELOG(ERROR)
 #define ELOG_CRITICAL ELOG(CRITICAL)
 
+#define MELOG_TRACE(id) ELOG(INFO, id)
+#define MELOG_DEBUG(id) ELOG(DEBUG, id)
+#define MELOG_INFO(id) ELOG(INFO, id)
+#define MELOG_WARN(id) ELOG(WARN, id)
+#define MELOG_ERROR(id) ELOG(ERROR, id)
+#define MELOG_CRITICAL(id) ELOG(CRITICAL, id)
+
 #define ELOGT ELOG_TRACE
 #define ELOGD ELOG_DEBUG
 #define ELOGI ELOG_INFO
 #define ELOGW ELOG_WARN
 #define ELOGE ELOG_ERROR
-#define ELOGC ELOG_CRITICAL
+#define ELOGC ELOG_CRITICAL

src/easylog/tests/test_easylog.cpp

@@ -61,4 +61,23 @@ TEST_CASE("test basic") {
   ELOG_DEBUG << "debug log";
   ELOGD << "debug log";
   CHECK(get_last_line(filename).rfind("debug log") != std::string::npos);
+
+  // test multiple instance
+  std::string other_filename = "other.txt";
+  std::filesystem::remove(other_filename);
+  constexpr size_t InstanceId = 2;
+  easylog::init_log<InstanceId>(Severity::DEBUG, other_filename, false);
+  ELOG(INFO, InstanceId) << "ok in other txt";
+  easylog::flush<InstanceId>();
+  CHECK(get_last_line(other_filename).rfind("ok in other txt") !=
+        std::string::npos);
+  MELOG_INFO(InstanceId) << "test in other";
+  easylog::flush<InstanceId>();
+  CHECK(get_last_line(other_filename).rfind("test in other") !=
+        std::string::npos);
+
+  MELOGV(INFO, InstanceId, "it is a test %d", 42);
+  easylog::flush<InstanceId>();
+  CHECK(get_last_line(other_filename).rfind("it is a test 42") !=
+        std::string::npos);
 }