opentracing 2.4.0

入站请求

在你的服务器请求处理程序代码中的某个地方

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

作用域和进程内传播

为了在使用的请求局部存储中获取/设置当前活动Span，OpenTracing要求每个Tracer都包含一个ScopeManager，它通过Scope提供对活动Span的访问。任何Span都可以转移到另一个任务或线程，但不能是Scope。

# Access to the active span is straightforward.
scope = tracer.scope_manager.active()
if scope is not None:
    scope.span.set_tag('...', '...')

常见情况是启动一个Scope，它通过ScopeManager自动注册为进程内传播。

请注意，start_active_span('...')在Scope.close()时会自动完成span（与start_active_span('...', finish_on_close=False)不同，它不会完成）。

# 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:
    span.set_tag('error', '...')
finally:
    scope.close()

如果有作用域，它将作为任何新启动的Span的父级，除非程序员在start_span()/start_active_span()时传递ignore_active_span=True或明确指定父级上下文

scope = tracer.start_active_span('someWork', ignore_active_span=True)

每个服务/框架都应该提供一个特定的ScopeManager实现，它依赖于自己的请求局部存储（线程局部存储，或适用于异步框架的基于协程的存储等）。

作用域管理器

此项目在opentracing.scope_managers子模块中包含一系列ScopeManager实现，可以根据需要导入

from opentracing.scope_managers import ThreadLocalScopeManager

存在针对thread-local（opentracing.scope_managers子模块的默认实例）、gevent、Tornado、asyncio和contextvars的实现

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 # fits for old asyncio applications, requires Python 3.4 or newer.
from opentracing.scope_managers.contextvars import ContextVarsScopeManager # for asyncio applications, requires Python 3.7 or newer.

注意，对于asyncio应用程序，由于自动将父span传播到子协程、任务或计划好的回调，因此最好使用ContextVarsScopeManager而不是AsyncioScopeManager。

测试

virtualenv env
. ./env/bin/activate
make bootstrap
make test

您可以使用tox运行测试。

tox

测试平台套件

一个设计用于测试API更改和实验功能的测试平台套件包含在testbed目录下。有关更多信息，请参阅测试平台README。

文档

virtualenv env
. ./env/bin/activate
make bootstrap
make docs

文档编写在 docs/_build/html。

许可证

Apache 2.0 许可证.

发布

在新的版本发布之前，请将自上次版本以来的更改摘要添加到CHANGELOG.rst。

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