How to Create a Generator Context Manager in Python with contextlib

Create a custom context manager with the @contextlib.contextmanager decorator to manage resources using a generator function.

Medium Python 3.9+ Aug 9, 2026 Comprehensions & generators 13 views 0 copies

contextlib context-manager generator resource-management

Python code

16 lines

Python 3.9+

import contextlib

@contextlib.contextmanager
def temporary_directory():
    """Yield a string and clean up after the block exits."""
    print("Creating temp directory...")
    dir_name = "/tmp/example"
    try:
        yield dir_name
    finally:
        print(f"Removing {dir_name}...")

if __name__ == "__main__":
    with temporary_directory() as tmp:
        print(f"Using: {tmp}")
    print("Done")

Output

stdout

Creating temp directory...
Using: /tmp/example
Removing /tmp/example...
Done

How it works

The @contextlib.contextmanager decorator turns a generator function into a context manager. The yield statement splits the code into two parts: everything before it runs on entry, and everything after runs on exit. Using try/finally around yield ensures cleanup code always executes, even if an exception occurs inside the with block. The yielded value becomes the as target available inside the with block.

Common mistakes

Forgetting the `try/finally` block around `yield` so cleanup runs on exceptions
Using `return` instead of `yield` inside the generator function
Not catching exceptions to suppress or transform them after the yield

Variations

Use `@contextlib.asynccontextmanager` for async with-blocks
Create a class-based context manager with `__enter__` and `__exit__` methods

Real-world use cases

Automatically closing database connections or file handles after a block completes.
Setting up and tearing down temporary test environments or fixtures in unit tests.
Acquiring and releasing thread locks or other synchronization primitives safely.

How to Create a Generator Context Manager in Python with contextlib

Python code

Output

How it works

Common mistakes

Variations

Real-world use cases

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Python code

Output

How it works

Common mistakes

Variations

Real-world use cases

More from Comprehensions & generators

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Tutorials

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