Python agent and CherryPy

The New Relic Python agent provides support for the CherryPy WSGI server. This includes automatically instrumenting the WSGI application entry point supplied to the CherryPy WSGI server. The automatic instrumentation will work if the CherryPyWSGIServer API function is used directly, or if egg:PasteScript#cherrypy is specified as the server to use when starting up the web application using PasteDeploy.

Integrated server

If you have manually integrated the creation of an instance of CherryPyWSGIServer into your application script, such as in:

from cherrypy import wsgiserver

def application(environ, start_response):
    status = '200 OK'
    output = 'Hello World!'

    response_headers = [('Content-type', 'text/plain'),
                        ('Content-Length', str(len(output)))]
    start_response(status, response_headers)

    return [output]

server = wsgiserver.CherryPyWSGIServer(('', 8080),
        application, server_name='')


and you are starting your WSGI application as a Python script directly with Python as:


all you need to instead do is run:

NEW_RELIC_CONFIG_FILE=newrelic.ini newrelic-admin run-python

Instead of defining the NEW_RELIC_CONFIG_FILE environment variable on the same line as executing the command, it can instead be separately exported and set in the process environment before running the command.


newrelic-admin run-python

The path newrelic.ini should be replaced with the appropriate absolute or relative path to the location of your actual Python agent configuration file.

Using PasteDeploy

If rather than manually integrating the call to startup the CherryPy WSGI server in your application code, you are using PasteDeploy with a configuration similar to:

use = egg:PasteScript#cherrypy
host =
port = 8080

all you instead need to do to start up your WSGI application is wrap the running of the paster command:

NEW_RELIC_CONFIG_FILE=newrelic.ini newrelic-admin run-program paster serve production.ini

Agent initialization

When using the newrelic-admin wrapper script with the CherryPy WSGI server, the agent will be automatically initialized when the web application starts. You do not need to make any code changes to your web application.

If you are not able to, or do not wish to use the newrelic-admin wrapper script, you can still manually add in calls to the agent API to initialize it when your web application starts.

As per instructions for integration with your Python application, this should be done as the very first step by your web application, after any module import paths are setup, but before any imports of the CherryPy WSGI server, separate application modules or any modules for frameworks being used.

For more help

Join the discussion about Python in the New Relic Online Technical Community! The Technical Community is a public platform to discuss and troubleshoot your New Relic toolset.

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