• Add dependencies with yield, a.k.a. exit steps, context managers, cleanup, teardown, ...
  • This allows adding extra code after a dependency is done. It can be used, for example, to close database connections.
  • Dependencies with yield can be normal or async, FastAPI will run normal dependencies in a threadpool.
  • They can be combined with normal dependencies.
  • It's possible to have arbitrary trees/levels of dependencies with yield and exit steps are handled in the correct order automatically.
  • It works by default in Python 3.7 or above. For Python 3.6, it requires the extra backport dependencies:
    • async-exit-stack
    • async-generator
  • New docs at Dependencies with yield.
  • Updated database docs SQL (Relational) Databases: Main FastAPI app.
  • PR #595.
• Fix sitemap.xml in website. PR #598 by @samuelcolvin.