Wrangler 2.5
Geralyn
A typical morning at the barn begins at 6:30. The crew (there are six of us wranglers) is mostly still asleep, so we power through our morning chores without too much trouble. We prepare breakfast for some of the skinnier horses who need extra calories, we give medication to the horses who need it, and get the barn prepped for the day.
Hi Amber, we were at the ranch two weeks ago and absolutely adored you and all of the other Wranglers. Our Wrangler for the week was Reo who is a wonderful young man and a great guide. I remember him giving you a hard time and teasing you. Never realized how much a Wrangler does. Thank you for your dedication in keeping these amazing animals healthy and happy and everything else you do to make the ranch such an amazing place to visit. I hope to be back at the ranch in the near future and will see you then.
Rewrites can be scary. Our goal for this version of Wrangler was backward compatibility with the original version, while significantly improving the developer experience. I'd like to take this opportunity to present 10 reasons why you should upgrade to the new Wrangler!
Previously, folks would have to install @cloudflare/wrangler globally on a system. This made it hard to use different versions of Wrangler across projects. Further, it was hard to install on some CI systems because of lack of access to a user's root folder. Sometimes, folks would forget to add the @cloudflare scope when installing, confusing them when a completely unrelated package was installed and didn't work as expected.
Let's fix that. We've simplified this by now publishing to the wrangler package, so you can run npm install wrangler and it works as expected. You can also install it locally to a project's package.json, like any other regular npm package. It also works across a much broader range of CPU architectures and operating systems, so you can use it on more machines.
It's now much simpler to get started with a new project. Previously, you would have to create a wrangler.toml configuration file, and fill it in with details about your cloudflare account, how the project was structured, setting up a custom build process and so on. We heard feedback from many of you who would get frustrated during this step, and how it would take many minutes before you could get to developing a simple Worker.
Let's fix that. You no longer need to create a configuration file when starting, and none of the fields are mandatory. Wrangler infers details about your account and project as you start developing, and you can add configuration incrementally when you need to.
In fact, you don't even need to install Wrangler to start! You can create a Worker (say, as index.js) and use npx (a utility that comes installed with node.js) to fetch Wrangler from the npm registry and start developing immediately!
We noticed users would struggle to set up a project with Wrangler, even after they'd installed Wrangler and configured wrangler.toml. Most users want to set up a package.json, commonly use typescript to write code, and set up git to track changes in this project. So, we expanded the wrangler init command to set up a production grade project. You can optionally choose to use typescript, install the official type definitions for Workers, and use git to track changes.
Wrangler typically runs a development server on our global network, setting up a local proxy when developing, so you can develop against a "real" environment in the cloud. This is great for making sure the code you develop will behave the same in development, and after you deploy it to production. The trade-off here is it's harder to develop code when you have a bad Internet connection, or if you're running tests on a CI machine. It's also marginally slower to iterate while coding. Users have asked us for a long time to be able to 'run' their code locally on their machines, so that they can iterate quickly and run tests in environments like CI.
Wrangler now lets you develop on your machine by simply calling wrangler dev --local, and no additional configuration. This is powered by Miniflare, a fully featured simulator of the Cloudflare Workers runtime. You can even toggle across 'edge' and 'local' modes by tapping the 'L' hotkey when developing; however you prefer!
It's useful to be able to "tail" a Worker's output to a terminal, and see what's going on in real time. While you can already view these logs in the Workers dashboard, some people are more comfortable seeing the logs in their terminal, and then slicing and dicing to debug any issues that may be occuring. Previously, you would have to checkout a Worker's repository locally, install dependencies, and then call wrangler tail in the project folder. This was clearly cumbersome, and relied on developer expertise to see something as simple as a Worker's logs.
Now you can simply call npx wrangler tail in your terminal, without any configuration or setup, and immediately see the logs that you expect. We use this ourselves to quickly inspect our production Workers and see what's going on inside them!
One of the worst feelings a developer can face is being presented with an error when writing code, and not knowing how to fix it and proceed. We heard feedback from many of you who were frustrated with the lack of error messages, and how you would spend hours trying to figure out what went wrong. We've now added new error and warning messages, so you can easily spot the problems in your code. When possible, we also include steps you can follow to fix your Worker, including things that you can simply copy and paste! This makes Wrangler much more friendly to use, and we promise the experience will only get better.
We introduced initial support for debugging Workers in Wrangler in September which enables debugging a Worker directly on our global network. However, getting started with debugging was still a bit cumbersome, because you would have to start Wrangler with an --inspect flag, then open a special page in your browser (chrome://inspect), configuring it to detect Wrangler running on a special port, and then launching the debugger. This would also mean you might have lost any debugging messages that were logged before you opened the Chrome developer tools.
We fixed this. Now you don't need to pass any special flags when starting up. You can simply hit the D hotkey when developing and a developer tools instance pops up in your browser. And by buffering the messages before you even start up the devtools, you don't lose any logs or errors! You can also use VS Code developer tools to directly hook into your Worker's debugging session!
Modern JavaScript isn't simply about the syntax that the language supports, but also writing code as modules, and leveraging the extremely broad ecosystem of community libraries and frameworks. Previously, Wrangler required that you set up webpack or a custom build with bundlers (like rollup, vite, or esbuild, to name a few) to consume libraries and modules. This introduces a lot of friction, especially when starting a new project and trying out new ideas.
Now, support for npm modules comes out of the box, with no extra configuration required! You can install any package from the npm registry, organize your own code with modules, and it all works as expected. We're also introducing an experimental node.js compatibility mode for using node.js modules that wouldn't previously work without setting up your own polyfills! This means you can use popular frameworks and libraries that you're already familiar with while focusing on delivering value to your users.
A rewrite should be judged not just by the new features that are implemented, but by how many existing issues are resolved. We went through hundreds of outstanding issues and bugs with Wrangler, and are happy to say that we solved almost all of them! Across the board, every command and feature got a facelift, bug fixes, and test coverage to make sure it doesn't break in the future. Developers on using Cloudflare Workers will be glad to hear that simply upgrading Wrangler will immediately fix previous concerns and problems. Which leads us to my absolute favorite feature...
Wrangler has always been special software for us. It represents the primary interface that developers use to interact and use Cloudflare Workers, and we have major plans for the future. We have invested time, effort and resources to make sure Wrangler is the best tool for developers to use, and we're excited to see what the future holds. This is a commitment to our users and community that we will only keep improving on this foundation, and folks can expect their feedback and concerns to be heard loud and clear.
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