feat: add Logger

index.ts

@@ -0,0 +1,73 @@
+import Pino from "pino";
+
+const ENV_VARIABLE_NAME = "KAUAI_LOG_LEVEL";
+
+const serializers = {
+  error: Pino.stdSerializers.err,
+  request: Pino.stdSerializers.req,
+  response: Pino.stdSerializers.res,
+};
+
+const formatters = {
+  level: (label: string): { level: string } => ({ level: label }),
+};
+
+export class Logger {
+  readonly #logger: Pino.Logger;
+
+  public constructor(
+    { level = Logger.getLevel(), ...options }: Pino.LoggerOptions = {},
+    logger = Pino({ level, formatters, serializers, ...options })
+  ) {
+    this.#logger = logger;
+  }
+
+  public child(params: Pino.Bindings = {}): Logger {
+    return new Logger({}, this.#logger.child(params));
+  }
+
+  public fatal(message: string, extra: Record<string, unknown> = {}): void {
+    this.#logger.fatal(extra, message);
+  }
+
+  public error(message: string, extra: Record<string, unknown> = {}): void {
+    this.#logger.error(extra, message);
+  }
+
+  public warn(message: string, extra: Record<string, unknown> = {}): void {
+    this.#logger.warn(extra, message);
+  }
+
+  public info(message: string, extra: Record<string, unknown> = {}): void {
+    this.#logger.info(extra, message);
+  }
+
+  public debug(message: string, extra: Record<string, unknown> = {}): void {
+    this.#logger.debug(extra, message);
+  }
+
+  public trace(message: string, extra: Record<string, unknown> = {}): void {
+    this.#logger.trace(extra, message);
+  }
+
+  public static getLevel(
+    env_name = ENV_VARIABLE_NAME
+  ): Exclude<keyof Logger, "child"> | "silent" {
+    const { [env_name]: LEVEL } = process.env;
+    const level = LEVEL?.trim().toLowerCase();
+
+    switch (level) {
+      case "trace":
+      case "debug":
+      case "info":
+      case "warn":
+      case "error":
+      case "fatal":
+        return level;
+      default:
+        return "silent";
+    }
+  }
+}
+
+export default new Logger({ level: Logger.getLevel() });