mdc

library1.2.1pypypi✓ verified 85d ago

A Python implementation of Mapped Diagnostic Context (MDC) for structured logging. MDC allows you to enrich log records with contextual key-value pairs, propagate context across threads and async code, and format logs as JSON. Current version 1.2.1, released on PyPI, with irregular releases.

observability

pip install mdc

github ↗package ↗

INSTALL

IMPORT

SIG · MDC

mdc

observabilitypythonv1.2.1

Install

2.7s avg

Import

73ms

Disk

21MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v1.2.1 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.076s · 23.3MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 2.7s · import 0.070s · 24MB

21MB installed

● package 21MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

MDC

✓ from mdc import MDC

MDCFormatter

✓ from mdc import MDCFormatter

MDCHandler

✓ from mdc import MDCHandler

Legacy class kept for compatibility

Basic usage: use MDC as a context manager to add key-value pairs to log records.

from mdc import MDC import logging # Set up logging handler = logging.StreamHandler() handler.setFormatter(MDCFormatter()) logging.getLogger().addHandler(handler) logging.getLogger().setLevel(logging.INFO) # Use MDC context with MDC(user_id='1234', ip='127.0.0.1'): logging.info('Processing request') # Output includes MDC fields

mdc --version

Debug

Known issues

breakingIn version 1.2.0, the MDC context was changed to support generators and argument catching. If you used MDC in older versions, ensure you are using the latest API.

fix

Upgrade to >=1.2.0 and review your usage of MDC as a decorator or context manager.

affects: <1.2.0

gotchaMDC context does NOT automatically propagate to child threads or async tasks unless you explicitly pass the context. Use MDC.copy() or MDC.get_context() to pass it manually.

fix

When spawning threads or tasks, manually copy the MDC context: context = MDC.get_context(); # pass to thread/task

affects: all

deprecatedMDCHandler is a legacy class kept for backward compatibility but may be removed in future versions. Use MDCFormatter with a standard logging Handler instead.

fix

Use from mdc import MDC, MDCFormatter and configure logging with MDCFormatter on any Handler.

affects: >=1.2.0

gotchaWhen using MDC as a decorator on generator functions, context is lost after the first yield. Version 1.2.1 fixed this bug, but older versions (<1.2.1) had this issue.

fix

Upgrade to 1.2.1 or later to preserve context throughout generator execution.

affects: <1.2.1

Errors

Common errors & fixes

ImportError: cannot import name 'MDCFormatter' from 'mdc'

You are using an older version of mdc that doesn't include MDCFormatter.

fix

Install the latest version: pip install --upgrade mdc

TypeError: 'int' object is not iterable

MDC expects values to be strings or objects convertible to string. Passing non-string values may cause formatting errors.

fix

Convert values to strings before passing to MDC: MDC(user_id=str(1234))

AttributeError: module 'mdc' has no attribute 'MDC'

Possibly installed a different package named mdc, or very old version.

fix

Run pip install --upgrade mdc. If problem persists, check your environment for conflicting mdc installations.

Upgrade

Version history

1.2.1latest on PyPI · released Sep 9, 2019

Audit

Dependencies

No dependency data recorded yet.

Agent activity

14 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/afriemann/mdc ↗

packagehttps://pypi.org/project/mdc/ ↗