Skip to main content

Tracing Instrumentation using OpenTracing API (http://opentracing.io)

Project description

[![PyPI version][pypi-img]][pypi] [![Build Status][ci-img]][ci]

# opentracing-python-instrumentation

A collection of instrumentation tools to enable tracing with
[OpenTracing API](http://opentracing.github.io).

## Usage

This library provides two types of instrumentation, explicit instrumentation
for server endpoints, and implicit instrumentation for client call sites.

Server endpoints are instrumented by creating a middleware class that:

1. initializes the specific tracer implementation
2. wraps incoming request handlers into a method that reads the incoming
tracing info from the request and creates a new tracing Span

Client call sites are instrumented implicitly by executing a set of
available `client_hooks` that monkey-patch some API points in several
common libraries like `SQLAlchemy`, `urllib2`, Tornado Async HTTP Client.
The initialization of those hooks is usually also done from the middleware
class's `__init__` method.

Here's an example of a middleware for
[Clay framework](https://github.com/uber/clay):

```python

from opentracing_instrumentation.request_context import RequestContextManager
from opentracing_instrumentation.http_server import before_request
from opentracing_instrumentation.http_server import WSGIRequestWrapper
from opentracing_instrumentation.client_hooks import install_all_patches


class TracerMiddleware(object):

def __init__(self, app, wsgi_app):
self.wsgi_app = wsgi_app
self.service_name = app.name

CONFIG.app_name = self.service_name
CONFIG.caller_name_headers.append('X-Uber-Source')
CONFIG.callee_endpoint_headers.append('X-Uber-Endpoint')

install_all_patches()
self.wsgi_app = create_wsgi_middleware(wsgi_app)
self.init_tracer()

def __call__(self, environ, start_response):
return self.wsgi_app(environ, start_response)

def init_tracer(self):
# code specific to your tracer implementation
pass


def create_wsgi_middleware(other_wsgi, tracer=None):
"""
Create a wrapper middleware for another WSGI response handler.
If tracer is not passed in, 'opentracing.tracer' is used.
"""

def wsgi_tracing_middleware(environ, start_response):
# TODO find out if the route can be retrieved from somewhere

request = WSGIRequestWrapper.from_wsgi_environ(environ)
span = before_request(request=request, tracer=tracer)

# Wrapper around the real start_response object to log
# additional information to opentracing Span
def start_response_wrapper(status, response_headers, exc_info=None):
if exc_info is not None:
span.add_tag('error', str(exc_info))
span.finish()

return start_response(status, response_headers)

with RequestContextManager(span=span):
return other_wsgi(environ, start_response_wrapper)

return wsgi_tracing_middleware
```

And here's an example for middleware in Tornado-based app:

```python
class TracerMiddleware(object):

def __init__(self):
# perform initialization similar to above, including installing
# the client_hooks

@gen.coroutine
def __call__(self, request, handler, next_mw):
request_wrapper = http_server.TornadoRequestWrapper(request=request)
span = http_server.before_request(request=request_wrapper)

@gen.coroutine
def next_middleware_with_span():
yield next_mw()

yield run_coroutine_with_span(span=span,
func=next_middleware_with_span)

span.finish()


def run_coroutine_with_span(span, func, *args, **kwargs):
"""Wrap the execution of a Tornado coroutine func in a tracing span.

This makes the span available through the get_current_span() function.

:param span: The tracing span to expose.
:param func: Co-routine to execute in the scope of tracing span.
:param args: Positional args to func, if any.
:param kwargs: Keyword args to func, if any.
"""
def mgr():
return RequestContextManager(span)

with tornado.stack_context.StackContext(mgr):
return func(*args, **kwargs)
```

## Development

```
virtualenv env
source env/bin/activate
make bootstrap
make test
```

## Releases

Before new release, add a summary of changes since last version to CHANGELOG.rst

```
pip install zest.releaser[recommended]
prerelease
release
git push origin master --follow-tags
python setup.py sdist upload -r pypi
postrelease
git push
```

[ci-img]: https://travis-ci.org/uber-common/opentracing-python-instrumentation.svg?branch=master
[ci]: https://travis-ci.org/uber-common/opentracing-python-instrumentation
[pypi-img]: https://img.shields.io/pypi/v/opentracing_instrumentation.svg
[pypi]: https://pypi.python.org/pypi/opentracing_instrumentation

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

opentracing_instrumentation-1.4.1.tar.gz (17.7 kB view hashes)

Uploaded Source

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page