Making sense of Mulesoft

I'm not doing too badly as a Mulesoft developer (which isn't my main job), given I've mostly been figuring it out as I go along. You won't find too many Stack Overflow answers for Mulesoft problems.

One of the reasons we're going all in on Mulesoft is we ended up with more integrations than anyone can track. Many of them are .NET APIs, many are SSIS packages… With Mulesoft, all the integrations are in one place, and can be managed through a single portal. Exchange also makes a pretty good repository for API specs.

The first problem I ran into is the file paths for the extracted Anypoint Studio files are damn long. Extracting them to the root directory solved that, for now. I read somewhere the problem could also be fixed in the Windows Registry, but haven't had time to find the key for that.

Mulesoft applications are Java applications, with vendor-specific components and dependencies, and they're developed in a vendor-specific variant of the Eclipse IDE. There's not much actual Java programming involved in developing the application - thankfully, as I hadn't worked properly with Java in roughly a decade. Most of it's 'low code', XML and DataWeave. A bit of YAML also.
Putting together the integration's main logic is actually easy. It's drag-and-drop, and add whatever parameters.

The difficult and messy part is the configuration - it spans multiple file paths, and they need referencing in multiple places, because the config will be context dependent. I recommend having all that in place first.
The '{mule-env}.yml' files contain usernames, passwords and client secrets for various things, but the application-specific configurations are in a global.xml file. Also, knowing what dependencies are needed is pure guesswork to begin with, unless you're very familiar with Java packages.

Another tricky part is DataWeave, which is the language used for the data transformations. The structure of a DataWeave file is easy to follow, but the syntax is something to learn.

I've done a little debugging in the Anypoint portal. Don't expect too much information in the logs, unless the developer configured the debug components a certain way in the application. If the bug is in a data transformation, the message queue will be a more useful place to look.