Introducing a logger for common use

packages/common/package.json

@@ -50,6 +50,7 @@
     "google-proto-files": "^0.8.0",
     "grpc": "^1.0.0",
     "is": "^3.0.1",
+    "log-driver": "^1.2.5",
     "methmeth": "^1.0.0",
     "modelo": "^4.2.0",
     "request": "^2.70.0",

packages/common/src/index.js

@@ -32,6 +32,12 @@ exports.GrpcService = require('./grpc-service.js');
  */
 exports.GrpcServiceObject = require('./grpc-service-object.js');
 
+/**
+ * @type {module:common/logger}
+ * @private
+ */
+exports.logger = require('./logger.js');
+
 /**
  * @type {module:common/operation}
  * @private

packages/common/src/logger.js

@@ -0,0 +1,68 @@
+/*!
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+ 'use strict';
+
+/*!
+ * @module common/logger
+ */
+
+var format = require('string-format-obj');
+var is = require('is');
+var logDriver = require('log-driver');
+
+/**
+ * Create a logger to print output to the console.
+ *
+ * @param {string=|object=} options - Configuration object. If a string, it is
+ *     treated as `options.level`.
+ * @param {string=} options.level - The minimum log level that will print to the
+ *     console. (Default: `error`)
+ * @param {string=} options.tag - A tag to use in log messages.
+ */
+function logger(options) {
+  if (is.string(options)) {
+    options = {
+      level: options
+    };
+  }
+
+  options = options || {};
+
+  return logDriver({
+    levels: [
+      'error',
+      'warn',
+      'info',
+      'debug',
+      'silly'
+    ],
+
+    level: options.level || 'error',
+
+    format: function() {
+      var args = [].slice.call(arguments);
+
+      return format('{level}{tag} {message}', {
+        level: args.shift().toUpperCase(),
+        tag: options.tag ? ':' + options.tag + ':' : '',
+        message: args.join(' ')
+      });
+    }
+  });
+}
+
+module.exports = logger;

packages/common/test/index.js

@@ -22,6 +22,7 @@ var proxyquire = require('proxyquire');
 var fakeGrpcOperation = {};
 var fakeGrpcService = {};
 var fakeGrpcServiceObject = {};
+var fakeLogger = {};
 var fakeOperation = {};
 var fakePaginator = {};
 var fakeService = {};
@@ -36,6 +37,7 @@ describe('common', function() {
       './grpc-operation.js': fakeGrpcOperation,
       './grpc-service.js': fakeGrpcService,
       './grpc-service-object.js': fakeGrpcServiceObject,
+      './logger.js': fakeLogger,
       './operation.js': fakeOperation,
       './paginator.js': fakePaginator,
       './service.js': fakeService,
@@ -49,10 +51,11 @@ describe('common', function() {
       GrpcOperation: fakeGrpcOperation,
       GrpcService: fakeGrpcService,
       GrpcServiceObject: fakeGrpcServiceObject,
+      logger: fakeLogger,
       Operation: fakeOperation,
+      paginator: fakePaginator,
       Service: fakeService,
       ServiceObject: fakeServiceObject,
-      paginator: fakePaginator,
       util: fakeUtil
     });
   });

packages/common/test/logger.js

@@ -0,0 +1,81 @@
+/*!
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+var assert = require('assert');
+var proxyquire = require('proxyquire');
+
+function fakeLogDriver(config) {
+  return config;
+}
+
+describe('logger base-functionality', function() {
+  var logger;
+
+  before(function() {
+    logger = proxyquire('../src/logger.js', {
+      'log-driver': fakeLogDriver
+    });
+  });
+
+  it('should create a logger with the correct levels', function() {
+    assert.deepEqual(logger().levels, [
+      'error',
+      'warn',
+      'info',
+      'debug',
+      'silly'
+    ]);
+  });
+
+  it('should use a specified level', function() {
+    var level = 'level';
+    assert.strictEqual(logger({ level: level }).level, level);
+  });
+
+  it('should treat a single arguments as the level', function() {
+    var level = 'level';
+    assert.strictEqual(logger(level).level, level);
+  });
+
+  it('should default level to error', function() {
+    assert.strictEqual(logger().level, 'error');
+  });
+
+  describe('formatting', function() {
+    var LEVEL = 'level-name';
+    var TAG = 'tag-name';
+    var MESSAGES = [
+      'message-1',
+      'message-2'
+    ];
+
+    it('should correctly format without a tag', function() {
+      var formatted = logger().format(LEVEL, MESSAGES[0], MESSAGES[1]);
+
+      assert.strictEqual(formatted, 'LEVEL-NAME message-1 message-2');
+    });
+
+    it('should correctly format with a tag', function() {
+      var formatted = logger({
+        tag: TAG
+      }).format(LEVEL, MESSAGES[0], MESSAGES[1]);
+
+      assert.strictEqual(formatted, 'LEVEL-NAME:tag-name: message-1 message-2');
+    });
+  });
+});