express-errorlog

Express Error Log

A very simple logger for Express 4.x.

• Install and use
• Configuration
• Sample Output
• License (MIT)

Install and use

Install as usual with NPM:

npm install --save express-errorlog

Then configure as the last route of your Express app:

var errorlog = require('express-errorlog');
app.use(errorlog);

In the code, various patterns can be used:

Direct response statuses

app.route('/somewhere', function(req, res, next) {
  next(404); // Simply interrupt with a 404 not found
});

Status, message and details

app.route('/somewhere', function(req, res, next) {
  next({
    status: 404,
    message: 'This will override the message',
    details: { // This will appear in the response
      key: 'value',
      any: [ 'sort', 'of', stuff ]
    }
  });
});

Errors to be logged only

app.route('/somewhere', function(req, res, next) {
  next({
    status: 404,
    message: 'This will override the message',
    details: { // This will appear in the response
      key: 'value',
      any: [ 'sort', 'of', stuff ]
    },
    error: new Error("This will not be transmitted to the client")
  });
});

Configuration

var errorlog = require('express-errorlog');
app.use(errorlog({
  logger: function/stream,
  render: true/false
}));

• logger: A function receiving the message to be logged or a stream that will be written to with the date and error message.

• render: A boolean, if true the response will be sent to the client using Express' own render(...) function.

  For log rotation use something similar to logrotate-stream.

Sample Output

Here is some sample output derived from the tests:

2015-03-30T16:45:01.661Z - GET /test-1 (400) - Bad Request
2015-03-30T16:45:01.682Z - GET /test-2 (499) - Unknown status 499
2015-03-30T16:45:01.689Z - GET /test-3 (500) - Unknown status 999
2015-03-30T16:45:01.694Z - GET /test-4 (401) - message for test-4
2015-03-30T16:45:01.699Z - GET /test-5 (402) - Payment Required
  >>> { testname: 'test-5' }
2015-03-30T16:45:01.704Z - GET /test-6 (403) - message for test-6
  >>> { testname: 'test-6' }
2015-03-30T16:45:01.707Z - GET /test-7 (500) - message for test-7
  >>> { testname: 'test-7' }
2015-03-30T16:45:01.711Z - GET /test-8 (500) - exception message for test-8
  >>> [Error: exception message for test-8]
  Error: exception message for test-8
    at /Users/pier/Workspace/js-express-errorlog/test/test.js:13:57
    at Layer.handle [as handle_request] (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/layer.js:82:5)
    at next (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/route.js:110:13)
    at Route.dispatch (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/route.js:91:3)
    at Layer.handle [as handle_request] (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/layer.js:82:5)
    at /Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/index.js:267:22
    at Function.proto.process_params (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/index.js:321:12)
    at next (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/index.js:261:10)
    at expressInit (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/middleware/init.js:23:5)
    at Layer.handle [as handle_request] (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/layer.js:82:5)
2015-03-30T16:45:01.715Z - GET /test-9 (410) - exception message for test-9
  >>> { [Error: exception message for test-9]
  status: 410,
  details: { testname: 'test-9' },
  extra: 'this only gets logged!' }
  Error: exception message for test-9
    at Error (native)
    at /Users/pier/Workspace/js-express-errorlog/test/test.js:16:15
    at Layer.handle [as handle_request] (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/layer.js:82:5)
    at next (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/route.js:110:13)
    at Route.dispatch (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/route.js:91:3)
    at Layer.handle [as handle_request] (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/layer.js:82:5)
    at /Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/index.js:267:22
    at Function.proto.process_params (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/index.js:321:12)
    at next (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/index.js:261:10)
    at expressInit (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/middleware/init.js:23:5)
2015-03-30T16:45:01.718Z - GET /test-0 (411) - message for test-0
  >>> { testname: 'test-0' }
  >>> { [Error: exception message for test-0]
  more1: 'some more details for test 0',
  more2: 'even more details for test 0' }
  Error: exception message for test-0
    at Error (native)
    at /Users/pier/Workspace/js-express-errorlog/test/test.js:24:15
    at Layer.handle [as handle_request] (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/layer.js:82:5)
    at next (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/route.js:110:13)
    at Route.dispatch (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/route.js:91:3)
    at Layer.handle [as handle_request] (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/layer.js:82:5)
    at /Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/index.js:267:22
    at Function.proto.process_params (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/index.js:321:12)
    at next (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/router/index.js:261:10)
    at expressInit (/Users/pier/Workspace/js-express-errorlog/node_modules/express/lib/middleware/init.js:23:5)

License (MIT)

Copyright (c) 2015 Pier Fumagalli and USRZ.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.