HTTP Server-Timing for Python Flask

 * Installation

   pip install server-timing-profiler

This is a library including middleware for using HTTP Server-Timing with Python. This header allows a server to send timing information from the backend, such as database access time, file reads, etc. The timing information can be then be inspected in the standard browser developer tools:

Features

• Middleware for injecting the server timing into the request Context and writing the Server-Timing header.

• Concurrency-safe structures for easily recording timings of multiple concurrency tasks.

• Parse Server-Timing headers as a client.

• Note: No browser properly supports sending the Server-Timing header as an HTTP Trailer so the Middleware only supports a normal header currently.

Browser Support

Browser support is required to view server timings easily. Because server timings are sent as an HTTP header, there is no negative impact to sending the header to unsupported browsers.

• Chrome 65 or higher is required to properly display server timings in the devtools.

Usage

Example usage is shown below. A fully runnable example is available in the example/ directory.

from flask import Flask, jsonify
import time

# Import ProfileManager
from profiler.profile_manager import ProfileManager

app = Flask(__name__)
'''
Bind you app object with ProfileManager and pass app object along with 'debug' mode to enable the
result in reposne headers. If PROD or DEV is set you will not get stats in reponse to make sure
even if you miss to comment this code in prod, it will not affect your application
'''
profiler = ProfileManager(app, 'debug')


@app.route("/test", methods=["GET"])
def hello():
    print 'test start sleep'

    '''
    To profile any code snippet or call to external services , 
    call the start with a unique key and after the code snippet call stop function. 
    Also make sure to add call stop function [profiler.stop('<key>')]  with the same
    key you started with, otherwise status will not be reflect.
    '''
    
    profiler.start('App 1')
    time.sleep(1)
    profiler.stop('App 1')

    profiler.start('App 2')
    time.sleep(2)
    profiler.stop('App 2')

    profiler.start('App 3')
    time.sleep(3)
    profiler.stop('App 3')

    profiler.start('App 4')
    time.sleep(4)
    profiler.stop('App 4')

    print 'test stop sleep'
    return jsonify({'success':True})

app.run(host="0.0.0.0",port=8080,debug=True)

Note: Recommended not to enable this in production environment