Flask-Latency is middleware to simulate latency in a Flask development environment. Useful for debugging race conditions and other production-like scenarios while on localhost.
By default it will only ever apply latency if app.debug is on, and if you have the config variables below set to a non-zero value.
- In your main application file, install the latency app as follows:
from flask_latency import Latency
Latency(app)-
Add the configuration variables mentioned below to
app.config. -
Finally, you'll likely want to run a development server that can properly handle multiple HTTP requests in parallel, even while one is sleeping. If you're using Flask's
app.run()or Flask-Script'sServercommand, be sure to passthreaded=Trueas a kwarg.
For example, change from:
app.run() OR server = Server(host="0.0.0.0", port=9000)
To:
app.run(threaded=True) OR server = Server(host="0.0.0.0", port=9000, threaded=True)
Amount of latency, in seconds, to apply before and after the request, respectively. Can be specified as a number, or as a 2 entry tuple of numbers to act as a range of possible values (a value between those numbers will be chosen at random).
Example:
# 300ms of latency, before the request is executed
FAKE_LATENCY_BEFORE = 0.3
# Between 500ms and 1s of latency, after the request is executed
FAKE_LATENCY_AFTER = (0.5, 1)MIT License
Author: Phil Freo