This is a panel for flask_debugtoolbar which enables the ability to view line profiling information from selected functions.
The line profile information comes from the line_profiler module, but you don't need to worry about that.
First, you need to get the package. Install it with pip:
pip install flask-debugtoolbar-lineprofilerpanel
Somewhere after you've set app.debug = True and before app.run, you need
to specify the flask_debugtoolbar panels that you want to use and include
'flask_debugtoolbar_lineprofilerpanel.panels.LineProfilerPanel' in that
list.
For example, here's a small flask app with the panel installed and with line profiling enabled for the hello_world:
from flask import Flask
app = Flask(__name__)
import flask_debugtoolbar
from flask_debugtoolbar_lineprofilerpanel.profile import line_profile
@app.route('/')
@line_profile
def hello_world():
return flask.render_template('hello_world.html')
if __name__ == '__main__':
app.debug = True
# Specify the debug panels you want
app.config['DEBUG_TB_PANELS'] = [
'flask_debugtoolbar.panels.versions.VersionDebugPanel',
'flask_debugtoolbar.panels.timer.TimerDebugPanel',
'flask_debugtoolbar.panels.headers.HeaderDebugPanel',
'flask_debugtoolbar.panels.request_vars.RequestVarsDebugPanel',
'flask_debugtoolbar.panels.template.TemplateDebugPanel',
'flask_debugtoolbar.panels.sqlalchemy.SQLAlchemyDebugPanel',
'flask_debugtoolbar.panels.logger.LoggingPanel',
'flask_debugtoolbar.panels.profiler.ProfilerDebugPanel',
# Add the line profiling
'flask_debugtoolbar_lineprofilerpanel.panels.LineProfilerPanel'
]
toolbar = flask_debugtoolbar.DebugToolbarExtension(app)
app.run()
Unlike the regular profile panel that comes with flask_debugtoolbar, the
line profiler will only profile functions you specifically tell it to. You can
either use it as a decorator or directly as a function.
from flask_debugtoolbar_lineprofilerpanel.profile import line_profile
# Using it as a decorator
@app.route('/profile')
@line_profile
def profile_page():
...
return flask.render_template('profile_page')
# Explicit argument
line_profile(some_function)
Note that if I had done line_profile(profile_page) in the example above, it
would've profiled the wrapper created by app.route. In general, you probably
just want to use line_profile as a decorator.
Also note that the following will profile the decorator wrapper, not the inner function.
# Using it incorrectly as a decorator
@line_profile
@app.route('/profile')
def profile_page():
...
return flask.render_template('profile_page')
Always use @line_profile as the inner-most decorator.
line_profiler is implemented as a C extension. Unfortunately, AppEngine does not support C extensions in the cloud, and dev_appserver simulates this restriction on your local machine. If you'd like to use line_profiler on your local machine, you can monkey-patch the AppEngine SDK to permit it. The Flask-DebugToolbar will make sure this plugin is disabled in production (it will catch any ImportErrors and disable the affected panel).
Simply open application/__init__.py, which should look something like this:
from __future__ import absolute_import
from flask import Flask
app = Flask('application')
app.config.from_object('application.settings')
if app.config['DEBUG']:
from werkzeug.debug import DebuggedApplication
app.wsgi_app = DebuggedApplication(app.wsgi_app, evalex=True)
from flask.ext.debugtoolbar import DebugToolbarExtension
toolbar = DebugToolbarExtension(app)
import application.urls
and insert the monkey-patch, like so:
from __future__ import absolute_import
from flask import Flask
app = Flask('application')
app.config.from_object('application.settings')
if app.config['DEBUG']:
from werkzeug.debug import DebuggedApplication
app.wsgi_app = DebuggedApplication(app.wsgi_app, evalex=True)
# We can't use LineProfiler in production because it requires a C-extension,
# but we can monkey-patch it in here for use on the dev server:
try:
import os, sys, re
if 'SERVER_SOFTWARE' in os.environ and os.environ['SERVER_SOFTWARE'].startswith('Dev'):
# white-list the line_profiler C extension
sys.meta_path[3]._enabled_regexes.append(re.compile(r'.*line_profiler.*'))
from flask_debugtoolbar_lineprofilerpanel.profile import line_profile
## import the methods you want to profile here, and whitelist them with line_profile:
#from application.views import YourViewClass
#
#line_profile(YourViewClass.the_method_you_want_to_profile)
#line_profile(YourViewClass.another_method_you_want_to_profile)
except:
pass
# Make sure the monkey-patch is applied before you instantiate the DebugToolbarExtension.
from flask.ext.debugtoolbar import DebugToolbarExtension
toolbar = DebugToolbarExtension(app)
import application.urls