Metadata-Version: 2.4
Name: grelmicro
Version: 0.20.0
Summary: grelmicro is a lightweight toolkit for building Python applications that need to coordinate work across processes
Project-URL: Documentation, https://grelinfo.github.io/grelmicro
Project-URL: Repository, https://github.com/grelinfo/grelmicro.git
Project-URL: Issues, https://github.com/grelinfo/grelmicro/issues
Author-email: Loïc Gremaud <grelinfo@gmail.com>
License-Expression: MIT
License-File: LICENSE
Keywords: anyio,async,asyncio,cache,circuit-breaker,cloud-native,containerized,distributed-lock,distributed-systems,fastapi,health-checks,kubernetes,leader-election,logging,microservice,microservice-patterns,modular-monolith,opentelemetry,postgresql,pydantic,rate-limiter,redis,self-contained-systems,task-scheduler,tracing
Classifier: Development Status :: 1 - Planning
Classifier: Environment :: Web Environment
Classifier: Framework :: AsyncIO
Classifier: Framework :: FastAPI
Classifier: Framework :: Pydantic
Classifier: Framework :: Pydantic :: 2
Classifier: Intended Audience :: Developers
Classifier: Intended Audience :: Information Technology
Classifier: Intended Audience :: System Administrators
Classifier: License :: OSI Approved :: MIT License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3 :: Only
Classifier: Programming Language :: Python :: 3.11
Classifier: Programming Language :: Python :: 3.12
Classifier: Programming Language :: Python :: 3.13
Classifier: Programming Language :: Python :: 3.14
Classifier: Topic :: Internet
Classifier: Topic :: Software Development
Classifier: Topic :: Software Development :: Libraries
Classifier: Topic :: Software Development :: Libraries :: Application Frameworks
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Classifier: Typing :: Typed
Requires-Python: >=3.11
Requires-Dist: anyio>=4.0.0
Requires-Dist: fast-depends>=2.0.0
Requires-Dist: pydantic-extra-types>=2.11.0
Requires-Dist: pydantic-settings>=2.5.0
Requires-Dist: pydantic>=2.5.0
Provides-Extra: kubernetes
Requires-Dist: lightkube>=0.15.0; extra == 'kubernetes'
Provides-Extra: opentelemetry
Requires-Dist: opentelemetry-api>=1.20.0; extra == 'opentelemetry'
Requires-Dist: opentelemetry-sdk>=1.20.0; extra == 'opentelemetry'
Provides-Extra: postgres
Requires-Dist: asyncpg>=0.30.0; extra == 'postgres'
Provides-Extra: redis
Requires-Dist: redis>=5.0.0; extra == 'redis'
Provides-Extra: sqlite
Requires-Dist: aiosqlite>=0.20.0; extra == 'sqlite'
Provides-Extra: standard
Requires-Dist: orjson>=3.10.11; extra == 'standard'
Provides-Extra: structlog
Requires-Dist: orjson>=3.10.11; extra == 'structlog'
Requires-Dist: structlog>=24.1.0; extra == 'structlog'
Description-Content-Type: text/markdown

<p align="center">
  <a href="https://grelinfo.github.io/grelmicro">
    <img alt="grelmicro" class="grel-wordmark" src="https://raw.githubusercontent.com/grelinfo/grelmicro/main/docs/img/logo/wordmark.svg" width="520">
  </a>
</p>

<p align="center">
  <em>Async-first toolkit. Microservice patterns inside.</em>
</p>

<p align="center">
  A Python toolkit for distributed systems: microservices, modular monoliths, and self-contained systems.
</p>

<p align="center">
  <a href="https://pypi.org/project/grelmicro/"><img alt="PyPI - Version" src="https://img.shields.io/pypi/v/grelmicro"></a>
  <a href="https://pypi.org/project/grelmicro/"><img alt="PyPI - Python Version" src="https://img.shields.io/pypi/pyversions/grelmicro"></a>
  <a href="https://github.com/grelinfo/grelmicro/blob/main/LICENSE"><img alt="License: MIT" src="https://img.shields.io/badge/License-MIT-green.svg"></a>
  <a href="https://codecov.io/gh/grelinfo/grelmicro"><img alt="codecov" src="https://codecov.io/gh/grelinfo/grelmicro/graph/badge.svg?token=GDFY0AEFWR"></a>
  <a href="https://github.com/astral-sh/uv"><img alt="uv" src="https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/uv/main/assets/badge/v0.json"></a>
  <a href="https://github.com/astral-sh/ruff"><img alt="Ruff" src="https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json"></a>
  <a href="https://github.com/astral-sh/ty"><img alt="ty" src="https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ty/main/assets/badge/v0.json"></a>
</p>

> **Project status: Active development.** grelmicro is pre-1.0. The public API is not yet stable. Breaking changes are allowed on `MINOR` bumps (`0.14.0` → `0.15.0`) and never on `PATCH`. Pin the minor: `grelmicro>=0.14.0,<0.15.0`. After `1.0.0`, standard semver applies. See the [versioning policy](https://github.com/grelinfo/grelmicro/blob/main/CONTRIBUTING.md#about-grelmicro-versions).

______________________________________________________________________

**Documentation**: [https://grelinfo.github.io/grelmicro/](https://grelinfo.github.io/grelmicro)

**Source Code**: [https://github.com/grelinfo/grelmicro](https://github.com/grelinfo/grelmicro)

______________________________________________________________________

## Why grelmicro

Stop reinventing the wheel. grelmicro ships microservice patterns as small, composable modules with pluggable backends: locks, rate limits, circuit breakers, cache, logging, health checks, and task scheduling. Async-first, type-safe, and battle-tested in production.

It is built for any Python application that coordinates work across processes, workers, or replicas. The same primitives serve every **distributed system**, whether you call it **microservices**, a **modular monolith**, or a **self-contained system**. A distributed lock is a distributed lock whether your system is one process or fifty. It fits naturally into **cloud-native applications**, **containerized apps**, and **Kubernetes** deployments.

- **Micro**: one focused primitive per module, each a canonical microservice pattern (distributed lock, leader election, rate limiter, circuit breaker, health check API, externalised configuration).
- **Fast**: small footprint by design. We keep the layers thin so your code stays quick.
- **Async-first**: every I/O call is `async` / `await`. Drops into FastAPI, FastStream, and any AnyIO-based stack.
- **Backend-agnostic**: each primitive is a protocol. Swap Redis for PostgreSQL or SQLite without touching application code.
- **Railguarded**: 100% pytest coverage, ty-checked, ruff-linted, Pydantic-validated. Pre-1.0 API may shift on minor bumps. `1.x` commits to standard semver.

## Modules

| Module | Summary |
|---|---|
| [**Cache**](https://grelinfo.github.io/grelmicro/cache/) | `@cached` decorator with per-key stampede protection. In-memory `TTLCache` or `RedisCacheBackend`. |
| [**Synchronization**](https://grelinfo.github.io/grelmicro/sync/) | Distributed `Lock`, `TaskLock`, `LeaderElection`. Redis, PostgreSQL, SQLite, Kubernetes, in-memory. |
| [**Task Scheduler**](https://grelinfo.github.io/grelmicro/task/) | Periodic task execution with optional distributed locking. Lightweight, not a Celery replacement. |
| [**Resilience**](https://grelinfo.github.io/grelmicro/resilience/) | [Circuit Breaker](https://grelinfo.github.io/grelmicro/resilience/circuit-breaker/) and [Rate Limiter](https://grelinfo.github.io/grelmicro/resilience/rate-limiter/) with pluggable algorithms (`TokenBucketConfig`, `GCRAConfig`). |
| [**Logging**](https://grelinfo.github.io/grelmicro/logging/) | 12-factor logging with JSON, LOGFMT, TEXT, or PRETTY output, structured error rendering, and OpenTelemetry trace context. |
| [**Tracing**](https://grelinfo.github.io/grelmicro/tracing/) | Unified instrumentation. `@instrument` creates OpenTelemetry spans and enriches log records with structured context. |
| [**Health**](https://grelinfo.github.io/grelmicro/health/) | Health check registry with concurrent runners and FastAPI liveness / readiness integration. |
| [**JSON**](https://grelinfo.github.io/grelmicro/json/) | Fast JSON via `orjson` when available, with automatic fallback to stdlib `json`. |

## Installation

```bash
pip install grelmicro
```

See the [Installation guide](https://grelinfo.github.io/grelmicro/installation/) for `uv` and `poetry` commands, plus optional extras for Redis, PostgreSQL, SQLite, Kubernetes, OpenTelemetry, and structlog.

## Example

### FastAPI integration

Create a file `main.py` with:

```python
import logging
from contextlib import asynccontextmanager

from fastapi import FastAPI, HTTPException, Request

import grelmicro
from grelmicro import cache, resilience, sync
from grelmicro.cache import JsonSerializer, TTLCache, cached
from grelmicro.cache.redis import RedisCacheBackend
from grelmicro.logging import configure_logging
from grelmicro.resilience import (
    CircuitBreaker,
    RateLimitExceededError,
    RateLimiter,
)
from grelmicro.resilience.redis import RedisRateLimiterBackend
from grelmicro.sync import LeaderElection, Lock
from grelmicro.sync.redis import RedisSyncBackend
from grelmicro.task import TaskManager

logger = logging.getLogger(__name__)

# === grelmicro ===
task = TaskManager()
sync.register(RedisSyncBackend("redis://localhost:6379/0"))
cache.register(RedisCacheBackend("redis://localhost:6379/0", prefix="myapp:"))
resilience.register(RedisRateLimiterBackend("redis://localhost:6379/0"))

leader_election = LeaderElection("leader-election")
task.add_task(leader_election)

ttl_cache = TTLCache(ttl=300, serializer=JsonSerializer())


# === FastAPI ===
@asynccontextmanager
async def lifespan(app):
    configure_logging()
    async with grelmicro.lifespan(task):
        yield


app = FastAPI(lifespan=lifespan)


# --- Cache: avoid redundant database queries ---
@cached(ttl_cache)
async def get_user(user_id: int) -> dict:
    return {"id": user_id, "name": "Alice"}


@app.get("/users/{user_id}")
async def read_user(user_id: int):
    return await get_user(user_id)


# --- Circuit Breaker: protect calls to an unreliable service ---
cb = CircuitBreaker("my-service")


@app.get("/")
async def read_root():
    async with cb:
        return {"Hello": "World"}


# --- Rate Limiter: protect endpoints from overload ---
api_limiter = RateLimiter.gcra("api", limit=100, window=60)


@app.get("/api")
async def api_endpoint(request: Request):
    try:
        await api_limiter.acquire_or_raise(key=request.client.host)
    except RateLimitExceededError as exc:
        raise HTTPException(
            status_code=429,
            detail="Too many requests",
            headers={"Retry-After": str(int(exc.retry_after))},
        )
    return {"status": "ok"}


# --- Distributed Lock: synchronize access to a shared resource ---
lock = Lock("shared-resource")


@app.get("/protected")
async def protected():
    async with lock:
        return {"status": "ok"}


# --- Interval Task: run locally on every worker ---
@task.interval(seconds=5)
def heartbeat():
    logger.info("heartbeat")


# --- Distributed Task: run once per interval across all workers ---
@task.interval(seconds=60, max_lock_seconds=300)
def cleanup():
    logger.info("cleanup")


# --- Leader-gated Task: only the leader executes ---
@task.interval(seconds=10, leader=leader_election)
def leader_only_task():
    logger.info("leader task")
```

## License

This project is licensed under the terms of the [MIT license](https://github.com/grelinfo/grelmicro/blob/main/LICENSE).
