redirect_stderr

ClassPrivateContextSource

with redirect_stderr(target: SupportsWrite):
    ...

A wrapped version of contextlib.redirect_stderr.

This context allows a syncstream.LineBuffer or its mirror to be configured as the redirect target without raising typehint errors.

tip

You do not need to use this context because a buffer like LineBuffer is already a context now.

Because the buffer context will make both stdout and stderr redirected, you may want to use this context if you do not want to redirect stdout.

Aliases

This class can be acquired by

import syncstream


syncstream.redirect_stderr
syncstream.base.redirect_stderr

Arguments

Argument	Type	Required	Description
target	SupportsWrite		A writable buffer supporting the write method.

Example

Redirect stderr to buffer

Codes

use_this_function.py

import syncstream
from syncstream.base import redirect_stderr


buffer = syncstream.LineBuffer(10)
with redirect_stderr(buffer):
    try:
        raise TypeError("test-error!")
    except Exception as exc:
        print(exc, file=buffer)

messages = buffer.read()
for mitem in messages:
    print(mitem)

Better codes

use_buffer_context_directly.py

import syncstream


buffer = syncstream.LineBuffer(10)
with buffer:  # Both the stdout and stderr are catched.
    try:
        raise TypeError("test-error!")
    except Exception as exc:
        print(exc, file=buffer)

messages = buffer.read()
for mitem in messages:
    print(mitem)

Results

test-error!