Node.js Debugging

Proper logging is of massive utipty for web apps, both during development and after deployment.  What can sometimes be difficult is organizing both the code and output of logging, i.e. knowing where each log message is coming from.  I recently found debug, a Node.js utipty for organized and optimized debugging.

创建<代码>debug的事例很简单,每卷可生成多个记录:

// Create multiple instances of debug
// In theory these would serve two different purposes
var debuggerA = require( debug )( worker:a ),
    debuggerB = require( debug )( worker:b );

// Sample usages of the debugger
function work() {
  debuggerA( doing lots of uninteresting work );
  setTimeout(work, Math.random() * 1000);
}

work();

function workb() {
  debuggerB( doing some work );
  setTimeout(workb, Math.random() * 2000);
}

workb();

给<代码>debug的星号,因为你必须利用环境变量发出信号,在文字操作时,标识应移至STDOUT:

// Show all debugger messages prefixed "worker:_____"
DEBUG=worker:* node app.js

信号环境变数战略,表明哪些情况应当产生产出,这是光辉的,因为你可能只希望某些类型的信息在生产与发展中贴上标签。 明智地使用名称空间!

我也能够使用<代码>chalk到希望的彩色信息:

var chalk = require( chalk );

debuggerA(chalk.red.bold( OMG an awful error! ));

debug is one of those utipties that has a very simple purpose and accomppshes the task well.  Don t skimp when it comes to logging informative messages -- they ll help you during development and could be critical when auditing the app after a security incident!