refactor: use standard Pino API for logging

- Remove messageKey config from logger (fixes pino-pretty display)
- Convert all logging to standard Pino API: log.info({data}, 'message')
- Update tests to match new logging behavior
- ECS format automatically converts msg -> message in production
- Cleaner, more readable logs matching Fastify documentation
- All 32 tests passing (25 unit + 7 integration)

Author: charlypa

src/server.js

@@ -84,9 +84,8 @@ server.addHook('onRequest', (request, reply, done) => {
         request.log.info({
             reqId: request.id,
             correlationId: request.correlationId,
-            message: 'Request size',
             size: `${request.headers['content-length']} bytes`
-        });
+        }, 'Request size');
     }
     done();
 });
@@ -108,32 +107,29 @@ server.addHook('onRequest', (request, reply, done) => {
         request.log.error({
             reqId: request.id,
             correlationId: request.correlationId,
-            message: "Route not found",
             url: sanitizedUrl,
             method: request.method,
             ip: request.ips
-        });
+        }, "Route not found");
         reply.code(HTTP_STATUS_CODES.NOT_FOUND);
         return reply.send({error: 'Not Found'});
     } else if (!isAuthenticated(request)) {
         request.log.warn({
             reqId: request.id,
             correlationId: request.correlationId,
-            message: "Unauthorized access attempt",
             url: sanitizedUrl,
             method: request.method,
             ip: request.ips
-        });
+        }, "Unauthorized access attempt");
         reply.code(HTTP_STATUS_CODES.UNAUTHORIZED);
         return reply.send({error: 'Unauthorized'});
     }
     request.log.info({
         reqId: request.id,
         correlationId: request.correlationId,
-        message: "Request authenticated",
         url: sanitizedUrl,
         method: request.method
-    });
+    }, "Request authenticated");
     done();
 });
 
@@ -142,27 +138,24 @@ server.addHook('onRequest', (request, reply, done) => {
     request.log.info({
         reqId: request.id,
         correlationId: request.correlationId,
-        message: 'Incoming request',
         url: request.url,
         method: request.method,
         ip: request.ips
-    });
+    }, 'Incoming request');
     done();
 });
 
 // Response logging hook with correlation ID
 server.addHook('onResponse', (request, reply, done) => {
     const duration = Date.now() - request.startTime;
-    const logData = {
+    request.log.info({
         reqId: request.id,
         correlationId: request.correlationId,
-        message: 'Request completed',
         url: request.url,
         method: request.method,
         statusCode: reply.statusCode,
         duration: `${duration}ms`
-    };
-    request.log.info(logData);
+    }, 'Request completed');
     done();
 });
 
@@ -208,7 +201,7 @@ server.get('/health', async (request, reply) => {
 
         reply.send(health);
     } catch (error) {
-        request.log.error({message: 'Health check failed', error});
+        request.log.error(error, 'Health check failed');
         reply.code(503).send({
             status: 'ERROR',
             timestamp: new Date().toISOString(),

src/utils/logger.js

@@ -22,15 +22,13 @@ export function createLogger() {
     if (isDevelopment) {
         // Pretty logs for development
         return pino({
-            messageKey: 'message',
             transport: {
                 target: 'pino-pretty',
                 options: {
                     colorize: true,
                     translateTime: 'HH:MM:ss Z',
                     ignore: 'pid,hostname',
-                    singleLine: false,
-                    messageKey: 'message'
+                    singleLine: false
                 }
             }
         });
@@ -55,15 +53,13 @@ export function createFastifyLogger() {
     if (isDevelopment) {
         // Pretty logs for development
         return {
-            messageKey: 'message',
             transport: {
                 target: 'pino-pretty',
                 options: {
                     colorize: true,
                     translateTime: 'HH:MM:ss',
                     ignore: 'pid,hostname',
-                    singleLine: false,
-                    messageKey: 'message'
+                    singleLine: false
                 }
             }
         };

test/unit/utils/logger-test.spec.js

@@ -62,12 +62,10 @@ describe('unit Tests for logger', function () {
             const loggerConfig = createFastifyLogger();
 
             expect(loggerConfig).to.exist;
-            expect(loggerConfig.messageKey).to.equal('message');
             expect(loggerConfig.transport).to.exist;
             expect(loggerConfig.transport.target).to.equal('pino-pretty');
             expect(loggerConfig.transport.options).to.exist;
             expect(loggerConfig.transport.options.colorize).to.equal(true);
-            expect(loggerConfig.transport.options.messageKey).to.equal('message');
         });
 
         it('should create production Fastify logger config with ECS format', function () {
@@ -88,12 +86,13 @@ describe('unit Tests for logger', function () {
     });
 
     describe('logger message field consistency', function () {
-        it('development logger should use message field', function () {
+        it('development logger should use standard Pino API', function () {
             delete process.env.NODE_ENV;
             const loggerConfig = createFastifyLogger();
 
-            expect(loggerConfig.messageKey).to.equal('message');
-            expect(loggerConfig.transport.options.messageKey).to.equal('message');
+            // Standard Pino API - no messageKey override needed
+            expect(loggerConfig.transport).to.exist;
+            expect(loggerConfig.transport.target).to.equal('pino-pretty');
         });
 
         it('should maintain ECS compliance in production', function () {