FastAPI Integration Guide

Learn how to integrate Sift Dev logging with your FastAPI applications.

1. Installation

Install the Sift Dev Logger SDK using pip:

pip install sift-dev-logger
pip install "sift-dev-logger[fastapi]"

2. Environment Setup

Create a .env file in your project root.

# Your Sift Dev endpoint and api key
SIFT_DEV_ENDPOINT=http://<YOUR-ORG-ID>.app.trysift.dev:8000
SIFT_DEV_INGEST_KEY=<YOUR-API-KEY>

# Optional configuration (defaults shown below)
SIFT_DEV_SERVICE_NAME=fastapi-app
SIFT_DEV_SERVICE_INSTANCE_ID=instance-1
ENV=unspecified

3. Configuration (Optional)

💡 Configuration Options

Environment variables are automatically detected from your system environment if present
Manual configuration via code will override environment variables
Configure must be called before using fastapi_logger or getLogger
FastAPI-specific features:
Automatic request and response logging
Optional request/response body capture
Performance metrics for each route
Error tracking with full stack traces
Request context in all logs
Async support out of the box

Configuration options and defaults

1from fastapi import FastAPI
2from sift_dev_logger import SiftDevConfig, configure, fastapi_logger
3
4# Optional: Configure with defaults or environment variables
5configure(SiftDevConfig(
6    sift_dev_endpoint="Initialize here, or set SIFT_DEV_ENDPOINT env var",
7    sift_dev_ingest_key="Initialize here, or set SIFT_DEV_INGEST_KEY env var",
8    service_name="fastapi-app",
9    service_instance_id="instance-1",
10    env="unspecified",
11    batch_delay_millis=5000
12))
13
14app = FastAPI()
15
16# Initialize the logger with your FastAPI app
17# Uses previous configuration, or creates a new default config if none exists
18fastapi_logger(app)

4. Usage

FastAPI middleware and custom logging

1from fastapi import FastAPI, HTTPException
2from sift_dev_logger import getLogger, SiftDevConfig, fastapi_logger
3
4app = FastAPI()
5
6# Initialize with custom configuration
7fastapi_logger(
8    app,
9    config=SiftDevConfig(service_name="custom-fastapi-app"),  # Optional custom config
10    max_body_size=50_000,  # Maximum body size to log (bytes)
11    ignored_paths={"/health", "/metrics"},  # Paths to exclude from logging
12    capture_request_body=True,  # Log request bodies (default: True)
13    capture_response_body=False  # Log response bodies (default: False)
14)
15
16# Get a logger for custom logging
17logger = getLogger()
18
19@app.get('/users/{user_id}')
20async def get_user(user_id: str):
21    # Custom log with request context
22    logger.info("Processing user request", extra={
23        "user_id": user_id,
24        "action": "get_user"
25    })
26    
27    try:
28        user = {"id": user_id, "name": "John Doe"}
29        return user
30    except Exception as error:
31        logger.error("User lookup failed", exc_info=error)
32        raise HTTPException(status_code=404, detail="Not found")

Configuring Uvicorn's internal logging

Instead of using the middleware, you can capture Uvicorn's internal logs by adding our handler to the existing loggers:

1import logging
2from sift_dev_logger import SiftDevHandler, SiftDevConfig
3
4# Configure Uvicorn loggers with Sift Dev
5loggers = [
6    "uvicorn",           # Server logs
7    "uvicorn.access",    # Access logs
8    "uvicorn.error",     # Error logs
9    "fastapi"            # FastAPI logs
10]
11
12# Create handler with custom config
13handler = SiftDevHandler(config=SiftDevConfig(service_name="fastapi-internal"))
14
15# Add handler to all Uvicorn loggers
16for logger_name in loggers:
17    logger = logging.getLogger(logger_name)
18    logger.setLevel(logging.INFO)
19    logger.addHandler(handler)

Using dictConfig for Uvicorn setup

Alternatively, configure Uvicorn logging using Python's dictConfig:

1from sift_dev_logger import SiftDevHandler
2
3LOGGING_CONFIG = {
4    "version": 1,
5    "disable_existing_loggers": False,
6    "formatters": {
7        "default": {
8            "format": "%(asctime)s :: %(name)s - %(message)s"
9        }
10    },
11    "handlers": {
12        "default": {
13            "formatter": "default",
14            "class": "logging.StreamHandler",
15            "stream": "ext://sys.stdout",
16        },
17        "siftdev": {
18            "()": "sift_dev_logger.handlers.SiftDevHandler.from_dict",
19            "formatter": "default",
20            "level": "INFO",
21            "config": {
22                "service_name": "fastapi-internal",
23                "service_instance_id": "instance-1",
24            }
25        }
26    },
27    "loggers": {
28        "uvicorn": {
29            "handlers": ["default", "siftdev"],
30            "level": "INFO",
31            "propagate": False,
32        },
33        "uvicorn.access": {
34            "handlers": ["default", "siftdev"],
35            "level": "INFO",
36            "propagate": False,
37        },
38        "uvicorn.error": {
39            "handlers": ["default", "siftdev"],
40            "level": "INFO",
41            "propagate": False,
42        },
43        "fastapi": {
44            "handlers": ["default", "siftdev"],
45            "level": "INFO",
46            "propagate": False,
47        }
48    }
49}

5. Advanced Usage

Next Steps

Now that you've set up logging in your FastAPI application:

View your logs in the Logs Dashboard
Set up alerts and notifications
Configure custom log attributes for better filtering
Explore our other framework integrations