Flask Integration Guide

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

1. Installation

Install the Sift Dev Logger SDK with Flask support:

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

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=flask-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 flask_logger or getLogger
Flask-specific features:
Automatic request and response logging
Performance metrics for each route
Error tracking with full stack traces
Request context in all logs

Configuration options and defaults

1from flask import Flask
2from sift_dev_logger import SiftDevConfig, configure
3from sift_dev_logger.flask import flask_logger
4
5# Optional: Configure with defaults or environment variables
6configure(SiftDevConfig(
7    sift_dev_endpoint="Initialize here, or set SIFT_DEV_ENDPOINT env var",
8    sift_dev_ingest_key="Initialize here, or set SIFT_DEV_INGEST_KEY env var",
9    service_name="flask-app",
10    service_instance_id="instance-1",
11    env="unspecified",
12    batch_delay_millis=5000
13))
14
15app = Flask(__name__)
16
17# Initialize the logger with your Flask app
18# Uses previous configuration, or creates a new default config if none exists
19flask_logger(app)

4. Usage

Flask middleware and custom logging

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

Configuring Flask's internal logging

Instead of using the middleware, you can capture Flask's internal logs (Werkzeug) by adding our handler to the existing logger:

1import logging
2from sift_dev_logger import SiftDevHandler, SiftDevConfig
3
4# Configure Werkzeug (Flask's default logger) with Sift Dev
5werkzeug_logger = logging.getLogger('werkzeug')
6werkzeug_logger.setLevel(logging.INFO)
7
8# Add SiftDev handler to capture Flask's internal logs
9handler = SiftDevHandler(config=SiftDevConfig(service_name="flask-internal"))
10werkzeug_logger.addHandler(handler)

5. Advanced Usage

Next Steps

Now that you've set up logging in your Flask 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