웹 로그, DB 쿼리문과 결과 로그 출력

lib/logger.ts

@@ -0,0 +1,50 @@
+type Level = "debug" | "info" | "warn" | "error";
+
+const PRIORITY: Record<Level, number> = {
+  debug: 0,
+  info: 1,
+  warn: 2,
+  error: 3,
+};
+
+function getMinLevel(): Level {
+  const env = process.env.LOG_LEVEL as Level | undefined;
+  if (env && env in PRIORITY) return env;
+  const appEnv = process.env.APP_ENV;
+  return appEnv === "production" ? "info" : "debug";
+}
+
+function shouldLog(level: Level): boolean {
+  return PRIORITY[level] >= PRIORITY[getMinLevel()];
+}
+
+function write(
+  level: Level,
+  ctx: string,
+  message: string,
+  data?: Record<string, unknown>
+): void {
+  if (!shouldLog(level)) return;
+  const ts = new Date().toISOString();
+  const tag = level.toUpperCase().padEnd(5);
+  const line = data
+    ? `[${ts}] [${tag}] [${ctx}] ${message} ${JSON.stringify(data)}`
+    : `[${ts}] [${tag}] [${ctx}] ${message}`;
+  if (level === "warn" || level === "error") {
+    console.error(line);
+  } else {
+    console.log(line);
+  }
+}
+
+export const logger = {
+  debug: (ctx: string, message: string, data?: Record<string, unknown>) =>
+    write("debug", ctx, message, data),
+  info: (ctx: string, message: string, data?: Record<string, unknown>) =>
+    write("info", ctx, message, data),
+  warn: (ctx: string, message: string, data?: Record<string, unknown>) =>
+    write("warn", ctx, message, data),
+  error: (ctx: string, message: string, data?: Record<string, unknown>) =>
+    write("error", ctx, message, data),
+  isEnabled: (level: Level): boolean => shouldLog(level),
+};