The Python Podcast.__init__

The Python Podcast.__init__

The podcast about Python and the people who make it great

28 February 2022

See The Structure Of Your Software At A Glance With Call Graphs From Code2Flow - E354

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As software projects grow and change it can become difficult to keep track of all of the logical flows. By visualizing the interconnections of function definitions, classes, and their invocations you can speed up the time to comprehension for newcomers to a project, or help yourself remember what you worked on last month. In this episode Scott Rogowski shares his work on Code2Flow as a way to generate a call graph of your programs. He explains how it got started, how it works, and how you can start using it to understand your Python, Ruby, and PHP projects.


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  • Your host as usual is Tobias Macey and today I’m interviewing Scott Rogowski about Code2Flow, a utility for generating "pretty good" call graphs for dynamic languages


  • Introductions
  • How did you get introduced to Python?
  • Can you describe what Code2Flow is and the story behind it?
  • What are some of the ways that a program’s call graph might be used?
  • How does the visual representation generated by Code2Flow help with exploring the structure of a project?
    • What are some of the alternative approaches/tools that might be used to gain similar insights?
    • What do you see as the overlap in utility between Code2Flow and e.g. SourceGraph?
  • Can you describe how the Code2Flow project is implemented?
    • How have the design and goals of the project changed since you first began working on it?
  • Given that Code2Flow is implemented in Python, how have you managed the parsing/processing of the other languages that you support?
  • Visualizing a complex program can quickly become very messy. How have you approached the layout of the output to enhance comprehension?
  • What are some of the situations where Code2Flow will be unable to provide a full picture of a program’s call graph?
  • What are some of the pieces of information that are unavailable due to the static analysis approach that you have taken?
  • Can you describe the process of applying Code2Flow to a project?
    • Once the structure is on display, what are some next steps that an individual or team might take to analyze and act on the information?
  • Given the static nature of the output, how might Code2Flow be incorporated in a CI/CD system to provide insight into the evolution of a projects structure?
  • What are the most interesting, innovative, or unexpected ways that you have seen Code2Flow used?
  • What are the most interesting, unexpected, or challenging lessons that you have learned while working on Code2Flow?
  • When is Code2Flow the wrong choice?
  • What do you have planned for the future of Code2Flow?

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Closing Announcements

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The intro and outro music is from Requiem for a Fish The Freak Fandango Orchestra / CC BY-SA

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