Flask-OpenTracing 0.1.0

OpenTracing support for Flask applications

Installation

Run the following command:

$ pip install Flask-Opentracing

Useage

This Flask extension allows for tracing of Flask apps using the OpenTracing API. All that it requires is for a FlaskTracing tracer to be initialized using an instance of an OpenTracing tracer. You can either trace all requests to your site, or use function decorators to trace certain individual requests.

Note: optional_args in both cases are any number of attributes (as strings) of flask.Request that you wish to set as tags on the created span

Trace All Requests

import opentracing
from flask_opentracing import FlaskTracer

app = Flask(__name__)

opentracing_tracer = ## some OpenTracing tracer implementation
tracer = FlaskTracer(opentracing_tracer, True, app, [optional_args])

Trace Individual Requests

import opentracing
from flask_opentracing import FlaskTracer

app = Flask(__name__)

opentracing_tracer = ## some OpenTracing tracer implementation
tracer = FlaskTracer(opentracing_tracer)

@app.route('/some_url')
@tracer.trace(optional_args)
def some_view_func():
    ...
    return some_view

Accessing Spans Manually

In order to access the span for a request, we’ve provided an method FlaskTracer.get_span(request) that returns the span for the request, if it is exists and is not finished. This can be used to log important events to the span, set tags, or create child spans to trace non-RPC events. If no request is passed in, the current request will be used.

Tracing an RPC

If you want to make an RPC and continue an existing trace, you can inject the current span into the RPC. For example, if making an http request, the following code will continue your trace across the wire:

@tracer.trace()
def some_view_func(request):
    new_request = some_http_request
    current_span = tracer.get_span(request)
    text_carrier = {}
    opentracing_tracer.inject(span, opentracing.Format.TEXT_MAP, text_carrier)
    for k, v in text_carrier.iteritems():
        request.add_header(k,v)
    ... # make request

Examples

See the examples folder to view and run an example of two Flask applications with integrated OpenTracing tracers.