Require named loggers

We want to make it easy for files to create loggers that point back to
the file generating a given log.

By exposing ONLY `getLogger` method we support a cleaner for the logger
syntax for the logger (rather than importing `logger` and having to use
`childLogger` in our code, we can just import `getChildLogger` and
assign the child logger to a local `logger` value).

This also ensures that all loggers are generated with a name (I suppose
someone could choose to name with an empty string).

Author: slifty

src/app.ts

@@ -1,8 +1,9 @@
 import express from 'express';
 import pinoHttp from 'pino-http';
 import { rootRouter } from './routers';
-import { logger } from './logger';
+import { getLogger } from './logger';
 
+const logger = getLogger(__filename);
 const app = express();
 app.use(pinoHttp({
   logger,

src/handlers/canonicalFieldsHandlers.ts

@@ -1,4 +1,4 @@
-import { logger } from '../logger';
+import { getLogger } from '../logger';
 import { db } from '../database';
 import { isCanonicalFieldArray } from '../types';
 import { ValidationError } from '../errors';
@@ -7,6 +7,8 @@ import type {
   Response,
 } from 'express';
 
+const logger = getLogger(__filename);
+
 const getCanonicalFields = (req: Request, res: Response): void => {
   db.sql('canonicalFields.fetchAll')
     .then((canonicalFields) => {

src/index.ts

@@ -1,7 +1,8 @@
 import dotenv from 'dotenv';
 import { app } from './app';
-import { logger } from './logger';
+import { getLogger } from './logger';
 
+const logger = getLogger(__filename);
 dotenv.config();
 
 const port = Number(process.env.PORT ?? 3000);

src/logger.ts

@@ -1,7 +1,10 @@
 import pino from 'pino';
+import type {
+  Logger,
+} from 'pino';
 
 const logger = pino({
   level: process.env.LOG_LEVEL ?? 'silent',
 });
 
-export { logger };
+export const getLogger = (name: string): Logger => logger.child({ name });

src/scripts/migrate.ts

@@ -1,7 +1,7 @@
-import { logger as root_logger } from '../logger';
+import { getLogger } from '../logger';
 import { migrate } from '../database';
 
-const logger = root_logger.child({ source: 'migrate' });
+const logger = getLogger(__filename);
 
 logger.info('Starting migrations...');
 migrate()