feat: add logger function

include/utils/logger.h

@@ -0,0 +1,22 @@
+#ifndef _LOG_H
+#define _LOG_H
+
+enum {
+    LOG_DEBUG,
+    LOG_INFO,
+    LOG_WARN,
+    LOG_ERROR,
+    LOG_FATAL
+};
+
+#define log_debug(...) log_printf(LOG_DEBUG, __VA_ARGS__)
+#define log_info(...) log_printf(LOG_INFO,  __VA_ARGS__)
+#define log_warn(...) log_printf(LOG_WARN,  __VA_ARGS__)
+#define log_error(...) log_printf(LOG_ERROR, __VA_ARGS__)
+#define log_fatal(...) log_printf(LOG_FATAL, __VA_ARGS__)
+
+extern int LOG_LEVEL;
+void log_perror(char *prefix);
+void log_printf(int level, const char *fmt, ...);
+
+#endif

src/utils/logger.c

@@ -0,0 +1,57 @@
+#include <time.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include "logger.h"
+
+int LOG_LEVEL = LOG_INFO; // default log level
+
+static const char *log_string[] = {
+    "[DEBUG]",
+    "[INFO]",
+    "[WARN]",
+    "[ERROR]",
+    "[FATAL]",
+};
+
+static const char *log_color[] = {
+    "\x1b[39m", // debug
+    "\x1b[32m", // info
+    "\x1b[33m", // warn
+    "\x1b[31m", // error
+    "\x1b[95m", // fatal
+};
+
+void log_printf(int level, const char *fmt, ...) {
+    if (level < LOG_LEVEL) { // skip low log level
+        return;
+    }
+    time_t t = time(NULL);
+    char time_str[20]; // YYYY-mm-dd HH:MM:SS (20 bytes)
+    time_str[strftime(time_str, 20, "%Y-%m-%d %H:%M:%S", localtime(&t))] = '\0'; // generate time str
+
+    va_list ap;
+    va_start(ap, fmt);
+    fprintf(stderr, "\x1b[36m[Bootstrap]\x1b[0m \x1b[90m%s\x1b[0m", time_str); // show log prefix
+    fprintf(stderr, " %s%s\x1b[0m ", log_color[level], log_string[level]); // show log level
+    vfprintf(stderr, fmt, ap); // output log content
+    fprintf(stderr, "\n"); // add LF after line
+    fflush(stderr);
+    va_end(ap);
+
+    if (level == LOG_FATAL) {
+        exit(1);
+    }
+}
+
+void log_perror(char *prefix) {
+    time_t t;
+    time(&t);
+    struct tm *lt = localtime(&t);
+    fprintf(stderr, "\x1b[36m[Bootstrap]\x1b[0m ");
+    fprintf(stderr, "\x1b[90m%04d-%02d-%02d %02d:%02d:%02d\x1b[0m",
+            lt->tm_year + 1900, lt->tm_mon, lt->tm_mday, lt->tm_hour, lt->tm_min, lt->tm_sec);
+    fprintf(stderr, " %s%s\x1b[0m ", log_color[3], log_string[3]); // error level
+    fflush(stderr);
+    perror(prefix);
+}