Enhance logger API: more levels (debug, trace, error, critical), add logger_from_config, update quickstart example, add logger_debug.hpp helper

Author: mbn-code

examples/quickstart.cpp

@@ -1,9 +1,14 @@
 #include "../include/logger.hpp"
+#include "../include/logger_config.hpp"
+#include <memory>
 
 int main() {
-    Logger log; // async by default
-    log.info("app.start").kv("version", "0.1").send();
-    log.error("db.fail").kv("query", "SELECT * FROM foo").kv("code", 10).send();
-    log.set_level(Logger::Level::Warning);
-    log.warn("low.battery").kv("percent", 15).send();
+    // Load config from file if exists, fallback to default async logger
+    auto log = c_log::logger_from_config("logger.json");
+    log->info("app.start").kv("version", "0.1");
+    log->error("db.fail").kv("query", "SELECT * FROM foo").kv("code", 10);
+    log->set_level(c_log::Level::Warning);
+    log->warn("low.battery").kv("percent", 15);
+    // manual flush happens automatically at destruction
+    return 0;
 }

include/logger.hpp

@@ -65,6 +65,32 @@ class Logger {
         cur_entry_ = Entry{event, Level::Info};
         return *this;
     }
+    Logger& debug(const std::string& event) {
+        flush_if_building();
+        cur_entry_ = Entry{event, Level::Debug};
+        return *this;
+    }
+    Logger& warning(const std::string& event) {
+        flush_if_building();
+        cur_entry_ = Entry{event, Level::Warning};
+        return *this;
+    }
+    Logger& warn(const std::string& event) { return warning(event); }
+    Logger& error(const std::string& event) {
+        flush_if_building();
+        cur_entry_ = Entry{event, Level::Error};
+        return *this;
+    }
+    Logger& trace(const std::string& event) {
+        flush_if_building();
+        cur_entry_ = Entry{event, Level::Trace};
+        return *this;
+    }
+    Logger& critical(const std::string& event) {
+        flush_if_building();
+        cur_entry_ = Entry{event, Level::Critical};
+        return *this;
+    }
     Logger& kv(const std::string& key, const std::string& val) {
         cur_entry_.fields.emplace_back(key, val);
         return *this;

include/logger_debug.hpp

@@ -0,0 +1,11 @@
+#pragma once
+#include <string>
+#include <iostream>
+namespace c_log {
+// Debug helper (quick log to stderr, compile-out in release if defined)
+#ifndef CLOG_DISABLE_DEBUG
+inline void debug_log(const std::string& msg) { std::cerr << "[cLog-debug] " << msg << std::endl; }
+#else
+inline void debug_log(const std::string&) {}
+#endif
+}