flask-queryinspect
flask-queryinspect copied to clipboard
noise
Flask extension to provide query metrics in headers and logs
Flask QueryInspect Extension
Flask-QueryInspect is a Flask extension that provides metrics on SQL queries executed for each request.
It assumes use of and relies upon SQLAlchemy as the underlying ORM.
I've used this method for several Flask projects and was finally inspired to turn it into an extension after seeing https://github.com/dobarkod/django-queryinspect.
Flask-QueryInspect tracks the count of SQL reads and writes, new DB connections, and total request and total query time for each request. It does not yet handle reporting of duplicate queries like Django-QueryInspect.
Installation
pip install Flask-QueryInspect
Usage
app = Flask(__name__)
qi = QueryInspect(app)
Configuration
QueryInspect has the following optional config vars that can be set in Flask's app.config:
| Variable | Default | Description |
|---|---|---|
| QUERYINSPECT_ENABLED | True | False to completely disable QueryInspect |
| QUERYINSPECT_HEADERS | True | Enable response header injection |
| QUERYINSPECT_HEADERS_COMBINED | True | Enable combined single header, else use Django QueryInspect's style |
| QUERYINSPECT_LOG | True | Enable logging, in Librato style |
Combined Header Format
X-QueryInspect-Combined: reads=1,writes=1,conns=0,q_time=0.2ms,r_time=2.9ms
Log Format
Logging is output using the standard Python logging module (logger name is 'flask_queryinspect') and formatted so it can be easily read by Librato, see: https://devcenter.heroku.com/articles/librato#custom-log-based-metrics
E.g.:
INFO measure#qi.r_time=2.9ms, measure#qi.q_time=0.2ms,count#qi.reads=1, count#qi.writes=1, count#qi.conns=0
Example App
Run the example server:
python example_app.py
And in another terminal:
curl -D - http://127.0.0.1:5000/
Notice the X-QueryInspect-Combined header.
noise