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Errors: Call the Plumber

With gulp running, when we update a file, the gulp-bots recompile stuff for us. We're like a factory for CSS.

But there's a problem, a big problem if you're like me and mess up a lot. Add a syntax error in layout.scss.

Now check out gulp. It exploded! It's not even running anymore. So even if I fix the error, gulp is dead. I'll probably refresh my browser for 30 minutes before I realize that gulp hasn't been running this entire time. And I'll spend the next 5 minutes composing an angry tweet.

Out of the box, Gulp supports error handlers where you say "Hey, instead of exploding all crazy, just call this function over here." But instead, I'll show you a really nice plugin called gulp-plumber that'll take care of this for us.

Go look for gulp-plumber. Copy its handy install statement, and paste that to get it downloading.

npm install --save-dev gulp-plumber

Now, usually, this is where we'd go copy the require statement. But since we added gulp-load-plugins, we can skip that!

Instead, let's get to work. We need to pipe gulp through this plugin before any logic that might cause an error. So right after gulp.src, say pipe(plugins.plumber()):

30 lines gulpfile.js
... lines 1 - 11
gulp.src(config.assetsDir+'/'+config.sassPattern)
.pipe(plugins.plumber(function(error) {
console.log(error.toString());
this.emit('end');
}))
... lines 17 - 18
.pipe(plugins.concat('main.css'))
... lines 20 - 30

Tip

The function(error) callback function was not shown in the video, but should be included. This prevents an issue when running gulp watch.

And yea, that's it. Go back and get gulp back and running:

gulp

Let's mess up layout.scss again! This time, gulp does show us the error, it just doesn't die anymore. How nice! When we fix the error, it recompiles. Robots, get back to work!

Tip

Plumber prevents gulp from throwing a proper error exit code. When building for production, you may want a proper error. If so, try using plumber() only in development:

.pipe(gulpif(!util.env.production, plumber(function(error) {
    console.log(error.toString());
    this.emit('end');
})))

Thanks to Nicolas Sauveur for the tip!

Leave a comment!

  • 2016-01-07 enkuso

    When using plugins, it should be:

    .pipe(plugins.if(!config.production, plumber()))

  • 2015-09-03 weaverryan

    Hey Nicolas!

    I like it a lot - very good point. I've added a note at the bottom of this chapter - thanks for sharing!

    Cheers!

  • 2015-08-28 Nicolas Sauveur

    Hello Ryan,

    Just ran into an issue. Plumber seems to prevent gulp to throw the correct exit code when the script fails. It is problematic when you build assets for production in a deployment workflow, and gulp fails silently.

    So I now use : .pipe(gulpif(!util.env.production, plumber()))