Implement support for logger provider.

This allows the users of 'unleash-server' to programatically
change the logger implemnentation. #175

docs/getting-started.md

@@ -37,4 +37,37 @@ Available unleash options includes:
 
 - databaseUrl 
 - port
-- logLevel - ('INFO', 'ERROR',)
+
+## How do I configure the log output?
+ 
+By default, `unleash` uses [log4js](https://github.com/nomiddlename/log4js-node) to log important information. It is possible to swap out the logger provider (only when using Unleash programatically). This enables filtering of log levels and easy redirection of output streams.
+ 
+### What is a logger provider?
+ 
+A logger provider is a function which takes the name of a logger and returns a logger implementation. For instance, the following code snippet shows how a logger provider for the global `console` object could be written:
+ 
+```javascript
+function consoleLoggerProvider (name) {
+  // do something with the name
+  return {
+    debug: console.debug.bind(console),
+    info: console.info.bind(console),
+    warn: console.warn.bind(console),
+    error: console.error.bind(console)
+  };
+}
+```
+ 
+The logger interface with its `debug`, `info`, `warn` and `error` methods expects format string support as seen in `debug` or the JavaScript `console` object. Many commonly used logging implementations cover this API, e.g. bunyan, pino or winston.
+ 
+### How do I set a logger provider?
+ 
+Custom logger providers need to be set *before requiring the `unleash-server` module*. The following example shows how this can be done:
+ 
+```javascript
+// first configure the logger provider
+const unleashLogger = require('unleash-server/logger');
+unleashLogger.setLoggerProvider(consoleLoggerProvider);
+ 
+// then require unleash-server and continue as normal
+const unleash = require('unleash-server');

lib/app.js

@@ -6,8 +6,7 @@ const bodyParser = require('body-parser');
 const cookieParser = require('cookie-parser');
 const validator = require('express-validator');
 const responseTime = require('response-time');
-const log4js = require('log4js');
+const logger = require('./logger')('app.js');
-const logger = require('./logger');
 const routes = require('./routes');
 const path = require('path');
 const errorHandler = require('errorhandler');
@@ -56,12 +55,10 @@ module.exports = function(config) {
     app.use(bodyParser.json({ strict: false }));
 
     if (config.enableRequestLogger) {
-        app.use(
+        app.use((req, res, next) => {
-            log4js.connectLogger(logger, {
+            next();
-                format: ':status :method :url :response-timems',
+            logger.info(`${res.statusCode} ${req.method} ${req.path}`);
-                level: 'auto', // 3XX=WARN, 4xx/5xx=ERROR
+        });
-            })
-        );
     }
 
     if (typeof config.preRouterHook === 'function') {

lib/db/client-instance-store.js

@@ -1,7 +1,7 @@
 /* eslint camelcase: "off" */
 'use strict';
 
-const logger = require('../logger');
+const logger = require('../logger')('client-instance-store.js');
 const COLUMNS = [
     'app_name',
     'instance_id',

lib/db/client-metrics-db.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const logger = require('../logger');
+const logger = require('../logger')('client-metrics-db.js');
 
 const METRICS_COLUMNS = ['id', 'created_at', 'metrics'];
 const TABLE = 'client_metrics';

lib/db/client-metrics-store.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const logger = require('../logger');
+const logger = require('../logger')('client-metrics-store.js');
 
 const { EventEmitter } = require('events');
 

lib/db/feature-toggle-store.js

@@ -6,7 +6,7 @@ const {
     FEATURE_ARCHIVED,
     FEATURE_REVIVED,
 } = require('../event-type');
-const logger = require('../logger');
+const logger = require('../logger')('client-toggle-store.js');
 const NotFoundError = require('../error/notfound-error');
 const FEATURE_COLUMNS = [
     'name',

lib/db/strategy-store.js

@@ -5,7 +5,7 @@ const {
     STRATEGY_DELETED,
     STRATEGY_UPDATED,
 } = require('../event-type');
-const logger = require('../logger');
+const logger = require('../logger')('strategy-store.js');
 const NotFoundError = require('../error/notfound-error');
 const STRATEGY_COLUMNS = ['name', 'description', 'parameters', 'built_in'];
 const TABLE = 'strategies';

lib/event-differ.test.js

@@ -3,11 +3,6 @@
 const { test } = require('ava');
 const eventDiffer = require('./event-differ');
 const { FEATURE_CREATED, FEATURE_UPDATED } = require('./event-type');
-const logger = require('./logger');
-
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
 
 test('fails if events include an unknown event type', t => {
     const events = [

lib/logger.js

@@ -1,19 +1,33 @@
 'use strict';
 
 const log4js = require('log4js');
-log4js.configure({
-    appenders: [{ type: 'console' }],
-});
 
-const logger = log4js.getLogger('unleash');
+let loggerProvider = getDefaultLogProvider();
 
-// TODO: make level configurable
+module.exports = exports = function getLogger(name) {
+    return loggerProvider(name);
+};
+
+exports.setLoggerProvider = function setLoggerProvider(provider) {
+    loggerProvider = provider;
+};
+
+function getDefaultLogProvider() {
+    let level;
     if (process.env.NODE_ENV === 'production') {
-    logger.setLevel(log4js.levels.ERROR);
+        level = log4js.levels.ERROR;
     } else if (process.env.NODE_ENV === 'test') {
-    logger.setLevel(log4js.levels.ERROR);
+        level = log4js.levels.FATAL;
     } else {
-    logger.setLevel(log4js.levels.DEBUG);
+        level = log4js.levels.DEBUG;
     }
 
-module.exports = logger;
+    log4js.configure({
+        appenders: [{ type: 'console' }],
+        levels: {
+            '[all]': level,
+        },
+    });
+
+    return log4js.getLogger;
+}

lib/logger.test.js

@@ -0,0 +1,22 @@
+'use strict';
+
+const { test } = require('ava');
+const createLogger = require('./logger');
+const logger = require('../logger');
+const sinon = require('sinon');
+
+test('should expose a setLoggerProvider function', t => {
+    t.true(logger.setLoggerProvider instanceof Function);
+});
+
+test('should create logger via custom logger provider', t => {
+    const provider = sinon.stub();
+    const loggerName = 'test';
+    const loggerImpl = {};
+    provider.withArgs(loggerName).returns(loggerImpl);
+    logger.setLoggerProvider(provider);
+
+    const log = createLogger(loggerName);
+
+    t.is(log, loggerImpl);
+});

lib/routes/admin-api/applications.test.js

@@ -3,16 +3,11 @@
 const { test } = require('ava');
 const store = require('./../../../test/fixtures/store');
 const supertest = require('supertest');
-const logger = require('../../logger');
 const getApp = require('../../app');
 
 const { EventEmitter } = require('events');
 const eventBus = new EventEmitter();
 
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
-
 function getSetup() {
     const stores = store.createStores();
     const app = getApp({

lib/routes/admin-api/archive.js

@@ -2,7 +2,7 @@
 
 const { Router } = require('express');
 
-const logger = require('../../logger');
+const logger = require('../../logger')('/admin-api/archive.js');
 const { FEATURE_REVIVED } = require('../../event-type');
 const ValidationError = require('../../error/validation-error');
 const validateRequest = require('../../error/validate-request');

lib/routes/admin-api/events.test.js

@@ -4,7 +4,6 @@ const { test } = require('ava');
 
 const store = require('./../../../test/fixtures/store');
 const supertest = require('supertest');
-const logger = require('../../logger');
 const getApp = require('../../app');
 
 const { EventEmitter } = require('events');
@@ -22,10 +21,6 @@ function getSetup() {
     return { base, eventStore: stores.eventStore, request: supertest(app) };
 }
 
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
-
 test('should get empty events list via admin', t => {
     t.plan(1);
     const { request, base } = getSetup();

lib/routes/admin-api/feature.js

@@ -3,7 +3,7 @@
 const { Router } = require('express');
 const joi = require('joi');
 
-const logger = require('../../logger');
+const logger = require('../../logger')('/admin-api/feature.js');
 const {
     FEATURE_CREATED,
     FEATURE_UPDATED,

lib/routes/admin-api/feature.test.js

@@ -3,16 +3,11 @@
 const { test } = require('ava');
 const store = require('./../../../test/fixtures/store');
 const supertest = require('supertest');
-const logger = require('../../logger');
 const getApp = require('../../app');
 
 const { EventEmitter } = require('events');
 const eventBus = new EventEmitter();
 
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
-
 function getSetup() {
     const base = `/random${Math.round(Math.random() * 1000)}`;
     const stores = store.createStores();

lib/routes/admin-api/metrics.js

@@ -2,7 +2,7 @@
 
 const { Router } = require('express');
 
-const logger = require('../../logger');
+const logger = require('../../logger')('/admin-api/metrics.js');
 const ClientMetrics = require('../../client-metrics');
 const { catchLogAndSendErrorResponse } = require('./route-utils');
 

lib/routes/admin-api/metrics.test.js

@@ -3,16 +3,11 @@
 const { test } = require('ava');
 const store = require('./../../../test/fixtures/store');
 const supertest = require('supertest');
-const logger = require('../../logger');
 const getApp = require('../../app');
 
 const { EventEmitter } = require('events');
 const eventBus = new EventEmitter();
 
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
-
 function getSetup() {
     const stores = store.createStores();
     const app = getApp({

lib/routes/admin-api/route-utils.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const logger = require('../../logger');
+const logger = require('../../logger')('route-utils.js');
 
 const catchLogAndSendErrorResponse = (err, res) => {
     logger.error(err);

lib/routes/admin-api/strategy.js

@@ -4,7 +4,7 @@ const { Router } = require('express');
 const joi = require('joi');
 
 const eventType = require('../../event-type');
-const logger = require('../../logger');
+const logger = require('../../logger')('/admin-api/strategy.js');
 const NameExistsError = require('../../error/name-exists-error');
 const extractUser = require('../../extract-user');
 const strategySchema = require('./strategy-schema');

lib/routes/admin-api/strategy.test.js

@@ -4,7 +4,6 @@ const { test } = require('ava');
 const store = require('./../../../test/fixtures/store');
 const supertest = require('supertest');
 const getApp = require('../../app');
-const logger = require('../../logger');
 
 const { EventEmitter } = require('events');
 const eventBus = new EventEmitter();
@@ -25,10 +24,6 @@ function getSetup() {
     };
 }
 
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
-
 test('add version numbers for /stategies', t => {
     t.plan(1);
     const { request, base } = getSetup();

lib/routes/backstage.test.js

@@ -3,16 +3,11 @@
 const { test } = require('ava');
 const store = require('./../../test/fixtures/store');
 const supertest = require('supertest');
-const logger = require('../logger');
 const getApp = require('../app');
 
 const { EventEmitter } = require('events');
 const eventBus = new EventEmitter();
 
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
-
 test('should use enable prometheus', t => {
     t.plan(0);
     const stores = store.createStores();

lib/routes/client-api/feature.test.js

@@ -3,16 +3,11 @@
 const { test } = require('ava');
 const store = require('./../../../test/fixtures/store');
 const supertest = require('supertest');
-const logger = require('../../logger');
 const getApp = require('../../app');
 
 const { EventEmitter } = require('events');
 const eventBus = new EventEmitter();
 
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
-
 function getSetup() {
     const base = `/random${Math.round(Math.random() * 1000)}`;
     const stores = store.createStores();

lib/routes/client-api/metrics.js

@@ -2,7 +2,7 @@
 
 const { Router } = require('express');
 const joi = require('joi');
-const logger = require('../../logger');
+const logger = require('../../logger')('client-api/metrics.js');
 
 const { clientMetricsSchema } = require('./metrics-schema');
 

lib/routes/client-api/metrics.test.js

@@ -3,16 +3,11 @@
 const { test } = require('ava');
 const store = require('./../../../test/fixtures/store');
 const supertest = require('supertest');
-const logger = require('../../logger');
 const getApp = require('../../app');
 
 const { EventEmitter } = require('events');
 const eventBus = new EventEmitter();
 
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
-
 function getSetup() {
     const stores = store.createStores();
     const app = getApp({

lib/routes/client-api/register.js

@@ -2,7 +2,7 @@
 
 const { Router } = require('express');
 const joi = require('joi');
-const logger = require('../../logger');
+const logger = require('../../logger')('/client-api/register.js');
 
 const { clientRegisterSchema } = require('./register-schema');
 

lib/routes/client-api/register.test.js

@@ -3,16 +3,11 @@
 const { test } = require('ava');
 const store = require('./../../../test/fixtures/store');
 const supertest = require('supertest');
-const logger = require('../../logger');
 const getApp = require('../../app');
 
 const { EventEmitter } = require('events');
 const eventBus = new EventEmitter();
 
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
-
 function getSetup() {
     const stores = store.createStores();
     const app = getApp({

lib/routes/health-check.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const logger = require('../logger');
+const logger = require('../logger')('health-check.js');
 const { Router } = require('express');
 
 exports.router = function(config) {

lib/routes/health-check.test.js

@@ -3,16 +3,11 @@
 const { test } = require('ava');
 const store = require('./../../test/fixtures/store');
 const supertest = require('supertest');
-const logger = require('../logger');
 const getApp = require('../app');
 
 const { EventEmitter } = require('events');
 const eventBus = new EventEmitter();
 
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
-
 function getSetup() {
     const stores = store.createStores();
     const db = stores.db;

lib/routes/index.test.js

@@ -3,16 +3,11 @@
 const { test } = require('ava');
 const store = require('./../../test/fixtures/store');
 const supertest = require('supertest');
-const logger = require('../logger');
 const getApp = require('../app');
 
 const { EventEmitter } = require('events');
 const eventBus = new EventEmitter();
 
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
-
 function getSetup() {
     const base = `/random${Math.round(Math.random() * 1000)}`;
     const stores = store.createStores();

lib/server-impl.js

@@ -2,7 +2,7 @@
 
 const { EventEmitter } = require('events');
 
-const logger = require('./logger');
+const logger = require('./logger')('server-impl.js');
 const migrator = require('../migrator');
 const getApp = require('./app');
 

logger.js

@@ -0,0 +1,5 @@
+'use strict';
+
+const logger = require('./lib/logger');
+
+exports.setLoggerProvider = logger.setLoggerProvider;

package.json

@@ -39,7 +39,7 @@
     "db-migrate": "db-migrate",
     "lint": "eslint .",
     "pretest": "npm run lint",
-    "test": "PORT=4243 ava lib/*.test.js lib/**/*.test.js lib/**/**/*.test.js lib/**/**/**/*.test.js test",
+    "test": "NODE_ENV=test PORT=4243 ava lib/*.test.js lib/**/*.test.js lib/**/**/*.test.js lib/**/**/**/*.test.js test",
     "test:docker": "./scripts/docker-postgres.sh",
     "test:watch": "npm run test -- --watch",
     "test:pg-virtualenv": "pg_virtualenv npm run test:pg-virtualenv-chai",

test/e2e/api/admin/event.e2e.test.js

@@ -2,11 +2,6 @@
 
 const { test } = require('ava');
 const { setupApp } = require('./../../helpers/test-helper');
-const logger = require('../../../../lib/logger');
-
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
 
 test.serial('returns events', async t => {
     t.plan(0);

test/e2e/api/admin/feature-archive.e2e.test.js

@@ -2,11 +2,6 @@
 
 const { test } = require('ava');
 const { setupApp } = require('./../../helpers/test-helper');
-const logger = require('../../../../lib/logger');
-
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
 
 test.serial('returns three archived toggles', async t => {
     t.plan(1);

test/e2e/api/admin/feature.e2e.test.js

@@ -2,11 +2,6 @@
 
 const { test } = require('ava');
 const { setupApp } = require('./../../helpers/test-helper');
-const logger = require('../../../../lib/logger');
-
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
 
 test.serial('returns three feature toggles', async t => {
     const { request, destroy } = await setupApp('feature_api_serial');

test/e2e/api/admin/metrics.e2e.test.js

@@ -2,11 +2,6 @@
 
 const { test } = require('ava');
 const { setupApp } = require('./../../helpers/test-helper');
-const logger = require('../../../../lib/logger');
-
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
 
 test.serial('should register client', async t => {
     t.plan(0);

test/e2e/api/admin/strategy.e2e.test.js

@@ -2,11 +2,6 @@
 
 const { test } = require('ava');
 const { setupApp } = require('./../../helpers/test-helper');
-const logger = require('../../../../lib/logger');
-
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
 
 test.serial('gets all strategies', async t => {
     t.plan(1);

test/e2e/health.e2e.test.js

@@ -2,11 +2,6 @@
 
 const { test } = require('ava');
 const { setupApp } = require('./helpers/test-helper');
-const logger = require('../../lib/logger');
-
-test.beforeEach(() => {
-    logger.setLevel('FATAL');
-});
 
 test('returns health good', async t => {
     t.plan(0);