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.
pip install Flask-QueryInspect
app = Flask(__name__)
qi = QueryInspect(app)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 |
X-QueryInspect-Combined: reads=1,writes=1,conns=0,q_time=0.2ms,r_time=2.9ms
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
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.