[feat] Automatically provide context based on INQUIRER

Resolves #532

README.md

@@ -95,6 +95,13 @@ export class MyService {
     private readonly logger: PinoLogger
   ) {}
 
+  constructor(
+    // If InjectPinoLogger is used without argument, it will attempt to deduce context
+    // using INQUIRER injection https://github.com/nestjs/docs.nestjs.com/issues/937
+    @InjectPinoLogger()
+    private readonly logger: PinoLogger
+  ) {}
+
   foo() {
     // PinoLogger has same methods as pino instance
     this.logger.trace({ foo: 'bar' }, 'baz %s', 'qux');

__tests__/no-context.spec.ts

@@ -55,7 +55,7 @@ describe('no context', () => {
 
         const ctrlLog = logs.find((v) => v.msg === msg);
         expect(ctrlLog).toBeTruthy();
-        expect(ctrlLog).not.toHaveProperty('context');
+        expect(ctrlLog?.context).toEqual(TestController.name);
       });
     });
   }

__tests__/utils/test-case.ts

@@ -83,6 +83,7 @@ export class TestCase {
     __resetSingletons();
 
     const app = await NestFactory.create(this.module, this.adapter, {
+      abortOnError: false,
       bufferLogs: true,
     });
     app.useLogger(app.get(Logger));

src/InjectPinoLogger.ts

@@ -1,16 +1,36 @@
-import { Inject, Provider } from '@nestjs/common';
+import { Inject, Provider, Scope } from '@nestjs/common';
+import { INQUIRER } from '@nestjs/core';
 import { PinoLogger } from './PinoLogger';
 
 const decoratedTokenPrefix = 'PinoLogger:';
 
 const decoratedLoggers = new Set<string>();
+const transientToken = getLoggerToken('');
 
 export function InjectPinoLogger(context = '') {
   decoratedLoggers.add(context);
   return Inject(getLoggerToken(context));
 }
 
 function createDecoratedLoggerProvider(context: string): Provider<PinoLogger> {
+  if (context === '') {
+    return {
+      provide: transientToken,
+      useFactory: (logger: PinoLogger, inquirer: any) => {
+        if (!inquirer) {
+          return logger;
+        }
+        if (typeof inquirer === 'string') {
+          logger.setContext(inquirer);
+        } else if (typeof inquirer === 'object') {
+          logger.setContext(inquirer.constructor.name);
+        }
+        return logger;
+      },
+      inject: [PinoLogger, INQUIRER],
+      scope: Scope.TRANSIENT,
+    };
+  }
   return {
     provide: getLoggerToken(context),
     useFactory: (logger: PinoLogger) => {