Metadata-Version: 2.1 Name: opentracing Version: 2.2.0 Summary: OpenTracing API for Python. See documentation at http://opentracing.io Home-page: https://github.com/opentracing/opentracing-python Author: The OpenTracing Authors Author-email: opentracing@googlegroups.com License: Apache License 2.0 Description: OpenTracing API for Python ========================== |GitterChat| |BuildStatus| |PyPI| |ReadTheDocs| This library is a Python platform API for OpenTracing. Required Reading ---------------- In order to understand the Python platform API, one must first be familiar with the `OpenTracing project `_ and `terminology `_ more specifically. Status ------ In the current version, ``opentracing-python`` provides only the API and a basic no-op implementation that can be used by instrumentation libraries to collect and propagate distributed tracing context. Future versions will include a reference implementation utilizing an abstract Recorder interface, as well as a `Zipkin `_-compatible Tracer. Usage ----- The work of instrumentation libraries generally consists of three steps: 1. When a service receives a new request (over HTTP or some other protocol), it uses OpenTracing's inject/extract API to continue an active trace, creating a Span object in the process. If the request does not contain an active trace, the service starts a new trace and a new *root* Span. 2. The service needs to store the current Span in some request-local storage, (called ``Span`` *activation*) where it can be retrieved from when a child Span must be created, e.g. in case of the service making an RPC to another service. 3. When making outbound calls to another service, the current Span must be retrieved from request-local storage, a child span must be created (e.g., by using the ``start_child_span()`` helper), and that child span must be embedded into the outbound request (e.g., using HTTP headers) via OpenTracing's inject/extract API. Below are the code examples for the previously mentioned steps. Implementation of request-local storage needed for step 2 is specific to the service and/or frameworks / instrumentation libraries it is using, exposed as a ``ScopeManager`` child contained as ``Tracer.scope_manager``. See details below. Inbound request ^^^^^^^^^^^^^^^ Somewhere in your server's request handler code: .. code-block:: python def handle_request(request): span = before_request(request, opentracing.global_tracer()) # store span in some request-local storage using Tracer.scope_manager, # using the returned `Scope` as Context Manager to ensure # `Span` will be cleared and (in this case) `Span.finish()` be called. with tracer.scope_manager.activate(span, True) as scope: # actual business logic handle_request_for_real(request) def before_request(request, tracer): span_context = tracer.extract( format=Format.HTTP_HEADERS, carrier=request.headers, ) span = tracer.start_span( operation_name=request.operation, child_of(span_context)) span.set_tag('http.url', request.full_url) remote_ip = request.remote_ip if remote_ip: span.set_tag(tags.PEER_HOST_IPV4, remote_ip) caller_name = request.caller_name if caller_name: span.set_tag(tags.PEER_SERVICE, caller_name) remote_port = request.remote_port if remote_port: span.set_tag(tags.PEER_PORT, remote_port) return span Outbound request ---------------- Somewhere in your service that's about to make an outgoing call: .. code-block:: python from opentracing import tags from opentracing.propagation import Format from opentracing_instrumentation import request_context # create and serialize a child span and use it as context manager with before_http_request( request=out_request, current_span_extractor=request_context.get_current_span): # actual call return urllib2.urlopen(request) def before_http_request(request, current_span_extractor): op = request.operation parent_span = current_span_extractor() outbound_span = opentracing.global_tracer().start_span( operation_name=op, child_of=parent_span ) outbound_span.set_tag('http.url', request.full_url) service_name = request.service_name host, port = request.host_port if service_name: outbound_span.set_tag(tags.PEER_SERVICE, service_name) if host: outbound_span.set_tag(tags.PEER_HOST_IPV4, host) if port: outbound_span.set_tag(tags.PEER_PORT, port) http_header_carrier = {} opentracing.global_tracer().inject( span_context=outbound_span, format=Format.HTTP_HEADERS, carrier=http_header_carrier) for key, value in http_header_carrier.iteritems(): request.add_header(key, value) return outbound_span Scope and within-process propagation ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ For getting/setting the current active ``Span`` in the used request-local storage, OpenTracing requires that every ``Tracer`` contains a ``ScopeManager`` that grants access to the active ``Span`` through a ``Scope``. Any ``Span`` may be transferred to another task or thread, but not ``Scope``. .. code-block:: python # Access to the active span is straightforward. scope = tracer.scope_manager.active() if scope is not None: scope.span.set_tag('...', '...') The common case starts a ``Scope`` that's automatically registered for intra-process propagation via ``ScopeManager``. Note that ``start_active_span('...')`` automatically finishes the span on ``Scope.close()`` (``start_active_span('...', finish_on_close=False)`` does not finish it, in contrast). .. code-block:: python # Manual activation of the Span. span = tracer.start_span(operation_name='someWork') with tracer.scope_manager.activate(span, True) as scope: # Do things. # Automatic activation of the Span. # finish_on_close is a required parameter. with tracer.start_active_span('someWork', finish_on_close=True) as scope: # Do things. # Handling done through a try construct: span = tracer.start_span(operation_name='someWork') scope = tracer.scope_manager.activate(span, True) try: # Do things. except Exception as e: scope.set_tag('error', '...') finally: scope.finish() **If there is a Scope, it will act as the parent to any newly started Span** unless the programmer passes ``ignore_active_span=True`` at ``start_span()``/``start_active_span()`` time or specified parent context explicitly: .. code-block:: python scope = tracer.start_active_span('someWork', ignore_active_span=True) Each service/framework ought to provide a specific ``ScopeManager`` implementation that relies on their own request-local storage (thread-local storage, or coroutine-based storage for asynchronous frameworks, for example). Scope managers ^^^^^^^^^^^^^^ This project includes a set of ``ScopeManager`` implementations under the ``opentracing.scope_managers`` submodule, which can be imported on demand: .. code-block:: python from opentracing.scope_managers import ThreadLocalScopeManager There exist implementations for ``thread-local`` (the default instance of the submodule ``opentracing.scope_managers``), ``gevent``, ``Tornado`` and ``asyncio``: .. code-block:: python from opentracing.scope_managers.gevent import GeventScopeManager # requires gevent from opentracing.scope_managers.tornado import TornadoScopeManager # requires tornado<6 from opentracing.scope_managers.asyncio import AsyncioScopeManager # requires Python 3.4 or newer. Development ----------- Tests ^^^^^ .. code-block:: sh virtualenv env . ./env/bin/activate make bootstrap make test You can use `tox `_ to run tests as well. .. code-block:: sh tox Testbed suite ^^^^^^^^^^^^^ A testbed suite designed to test API changes and experimental features is included under the *testbed* directory. For more information, see the `Testbed README `_. Instrumentation Tests --------------------- This project has a working design of interfaces for the OpenTracing API. There is a MockTracer to facilitate unit-testing of OpenTracing Python instrumentation. .. code-block:: python from opentracing.mocktracer import MockTracer tracer = MockTracer() with tracer.start_span('someWork') as span: pass spans = tracer.finished_spans() someWorkSpan = spans[0] Documentation ^^^^^^^^^^^^^ .. code-block:: sh virtualenv env . ./env/bin/activate make bootstrap make docs The documentation is written to *docs/_build/html*. LICENSE ^^^^^^^ `Apache 2.0 License <./LICENSE>`__. Releases ^^^^^^^^ Before new release, add a summary of changes since last version to CHANGELOG.rst .. code-block:: sh pip install zest.releaser[recommended] prerelease release git push origin master --follow-tags python setup.py sdist upload -r pypi upload_docs -r pypi postrelease git push .. |GitterChat| image:: http://img.shields.io/badge/gitter-join%20chat%20%E2%86%92-brightgreen.svg :target: https://gitter.im/opentracing/public .. |BuildStatus| image:: https://travis-ci.org/opentracing/opentracing-python.svg?branch-master :target: https://travis-ci.org/opentracing/opentracing-python .. |PyPI| image:: https://badge.fury.io/py/opentracing.svg :target: https://badge.fury.io/py/opentracing .. |ReadTheDocs| image:: http://readthedocs.org/projects/opentracing-python/badge/?version=latest :target: https://opentracing-python.readthedocs.io/en/latest/?badge=latest :alt: Documentation Status Keywords: opentracing Platform: any Classifier: Development Status :: 5 - Production/Stable Classifier: Intended Audience :: Developers Classifier: License :: OSI Approved :: Apache Software License Classifier: Programming Language :: Python :: 2.7 Classifier: Programming Language :: Python :: 3.5 Classifier: Programming Language :: Python :: 3.6 Classifier: Programming Language :: Python :: 3.7 Classifier: Programming Language :: Python :: Implementation :: PyPy Classifier: Topic :: Software Development :: Libraries :: Python Modules Provides-Extra: tests