654a271b82
Zipkin is a trend distributed tracing framewrok developed at Twitter. Such tracing is useful for both developers and operatos to understand the behavior of complex distributed systems and find performance bottlenecks. This patch provides a WSGI application using eventlet with tracing facility that complies with Zipkin. Signed-off-by: Yuichi Bando <bando.yuichi@lab.ntt.co.jp> Original commit modified for PEP-8 fixes. https://github.com/eventlet/eventlet/pull/218
79 lines
2.2 KiB
Python
79 lines
2.2 KiB
Python
import random
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from eventlet import wsgi
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from eventlet.zipkin import api
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from eventlet.zipkin._thrift.zipkinCore.constants import \
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SERVER_RECV, SERVER_SEND
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from eventlet.zipkin.http import \
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HDR_TRACE_ID, HDR_SPAN_ID, HDR_PARENT_SPAN_ID, HDR_SAMPLED
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_sampler = None
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__original_handle_one_response__ = wsgi.HttpProtocol.handle_one_response
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def _patched_handle_one_response(self):
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api.init_trace_data()
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trace_id = int_or_none(self.headers.getheader(HDR_TRACE_ID))
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span_id = int_or_none(self.headers.getheader(HDR_SPAN_ID))
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parent_id = int_or_none(self.headers.getheader(HDR_PARENT_SPAN_ID))
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sampled = bool_or_none(self.headers.getheader(HDR_SAMPLED))
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if trace_id is None: # front-end server
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trace_id = span_id = api.generate_trace_id()
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parent_id = None
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sampled = _sampler.sampling()
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ip, port = self.request.getsockname()[:2]
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ep = api.ZipkinDataBuilder.build_endpoint(ip, port)
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trace_data = api.TraceData(name=self.command,
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trace_id=trace_id,
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span_id=span_id,
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parent_id=parent_id,
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sampled=sampled,
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endpoint=ep)
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api.set_trace_data(trace_data)
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api.put_annotation(SERVER_RECV)
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api.put_key_value('http.uri', self.path)
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__original_handle_one_response__(self)
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if api.is_sample():
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api.put_annotation(SERVER_SEND)
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class Sampler(object):
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def __init__(self, sampling_rate):
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self.sampling_rate = sampling_rate
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def sampling(self):
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# avoid generating unneeded random numbers
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if self.sampling_rate == 1.0:
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return True
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r = random.random()
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if r < self.sampling_rate:
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return True
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return False
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def int_or_none(val):
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if val is None:
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return None
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return int(val, 16)
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def bool_or_none(val):
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if val == '1':
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return True
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if val == '0':
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return False
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return None
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def patch(sampling_rate):
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global _sampler
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_sampler = Sampler(sampling_rate)
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wsgi.HttpProtocol.handle_one_response = _patched_handle_one_response
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def unpatch():
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wsgi.HttpProtocol.handle_one_response = __original_handle_one_response__
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