In both cases, the AppMap tools will generate a PlantUML file, which will then be rendered as SVG. Once you’ve recorded a test case or an interactive session, you can use either the AppMap CLI or the AppMap extension for VSCode to generate a sequence diagram.

AppMap can record both test cases and live application API requests, so you can use either technique to acquire the diagram data. You can use AppMap with Ruby, Python, Java and JavaScript - you can find AppMap setup instructions here. For this, we’ll use AppMap, a free and open source runtime code analysis tool that I created. In order to generate a diagram of the code behavior, we need to record exactly what happens as the code runs.

Run your app and interact with it, either through its UI or by sending API requests from a tool like Postman.

So the first step in generating a sequence diagram is to run your code through a particular flow. Note Would you prefer to watch rather than read? Check out 'Auto-magically generate sequence diagrams of your Rails App using VSCode' on YouTubeĪ sequence diagram illustrates a particular code flow, like an HTTP request or the processing of a job. What if you could have the best of both worlds - sequence diagrams, with no effort? Read on, to learn how you can generate sequence diagrams just by running your code. And, being documentation, diagrams-as-code still suffer from the achilles heel of documentation, namely - getting out of date. Think: Markdown for diagrams.īut while it’s fairly easy (and rewarding!) to create sequence diagrams using text files, it still takes effort. But accordance with the “everything as code” movement, tools like PlantUML and Mermaid have kept sequence diagrams relevant by providing a fairly basic text language that can be used to generate sequence diagrams. Historically, creating a sequence diagram required specialized software.

And they are one of the best tools for developers and technical non-developers (like engineering managers and product managers) to use when discussing code design. Their inherent structure - objects flowing across the page, time flowing down the page - is intuitive and easy to learn. Sequence diagrams are frequently described as 'the best part of UML'.

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