Code import

venv/lib/python2.7/site-packages/eventlet/zipkin/wsgi.py

@@ -0,0 +1,78 @@
+import random
+
+from eventlet import wsgi
+from eventlet.zipkin import api
+from eventlet.zipkin._thrift.zipkinCore.constants import \
+    SERVER_RECV, SERVER_SEND
+from eventlet.zipkin.http import \
+    HDR_TRACE_ID, HDR_SPAN_ID, HDR_PARENT_SPAN_ID, HDR_SAMPLED
+
+
+_sampler = None
+__original_handle_one_response__ = wsgi.HttpProtocol.handle_one_response
+
+
+def _patched_handle_one_response(self):
+    api.init_trace_data()
+    trace_id = int_or_none(self.headers.getheader(HDR_TRACE_ID))
+    span_id = int_or_none(self.headers.getheader(HDR_SPAN_ID))
+    parent_id = int_or_none(self.headers.getheader(HDR_PARENT_SPAN_ID))
+    sampled = bool_or_none(self.headers.getheader(HDR_SAMPLED))
+    if trace_id is None:  # front-end server
+        trace_id = span_id = api.generate_trace_id()
+        parent_id = None
+        sampled = _sampler.sampling()
+    ip, port = self.request.getsockname()[:2]
+    ep = api.ZipkinDataBuilder.build_endpoint(ip, port)
+    trace_data = api.TraceData(name=self.command,
+                               trace_id=trace_id,
+                               span_id=span_id,
+                               parent_id=parent_id,
+                               sampled=sampled,
+                               endpoint=ep)
+    api.set_trace_data(trace_data)
+    api.put_annotation(SERVER_RECV)
+    api.put_key_value('http.uri', self.path)
+
+    __original_handle_one_response__(self)
+
+    if api.is_sample():
+        api.put_annotation(SERVER_SEND)
+
+
+class Sampler(object):
+    def __init__(self, sampling_rate):
+        self.sampling_rate = sampling_rate
+
+    def sampling(self):
+        # avoid generating unneeded random numbers
+        if self.sampling_rate == 1.0:
+            return True
+        r = random.random()
+        if r < self.sampling_rate:
+            return True
+        return False
+
+
+def int_or_none(val):
+    if val is None:
+        return None
+    return int(val, 16)
+
+
+def bool_or_none(val):
+    if val == '1':
+        return True
+    if val == '0':
+        return False
+    return None
+
+
+def patch(sampling_rate):
+    global _sampler
+    _sampler = Sampler(sampling_rate)
+    wsgi.HttpProtocol.handle_one_response = _patched_handle_one_response
+
+
+def unpatch():
+    wsgi.HttpProtocol.handle_one_response = __original_handle_one_response__