Merge pull request #16 from elgris/13-standard-propagators-support

Implements TextPropagator

Author: pglombardo

instana/propagator.py renamed to instana/http_propagator.py

@@ -0,0 +1,45 @@
+from __future__ import absolute_import
+
+import opentracing as ot
+from basictracer.context import SpanContext
+from instana import util, log
+
+prefix_tracer_state = 'X-INSTANA-'
+prefix_baggage = 'X-INSTANA-BAGGAGE-'
+field_name_trace_id = prefix_tracer_state + 'T'
+field_name_span_id = prefix_tracer_state + 'S'
+
+
+class TextPropagator():
+    """
+    A Propagator for Format.TEXT_MAP.
+    Does not support Baggage and Sampling
+    """
+
+    def inject(self, span_context, carrier):
+        carrier[field_name_trace_id] = '{0:x}'.format(span_context.trace_id)
+        carrier[field_name_span_id] = '{0:x}'.format(span_context.span_id)
+        if span_context.baggage is not None:
+            for k in span_context.baggage:
+                carrier[prefix_baggage+k] = span_context.baggage[k]
+
+    def extract(self, carrier):  # noqa
+        try:
+            if type(carrier) is dict or hasattr(carrier, "__dict__"):
+                dc = carrier
+            elif type(carrier) is list:
+                dc = dict(carrier)
+            else:
+                raise ot.SpanContextCorruptedException()
+
+            if field_name_trace_id in dc and field_name_span_id in dc:
+                trace_id = util.header_to_id(dc[field_name_trace_id])
+                span_id = util.header_to_id(dc[field_name_span_id])
+
+            return SpanContext(span_id=span_id,
+                               trace_id=trace_id,
+                               baggage={},
+                               sampled=True)
+
+        except Exception as e:
+            log.debug("extract error: ", str(e))

instana/text_propagator.py

@@ -4,10 +4,11 @@
 import opentracing as ot
 import instana.options as o
 import instana.sensor as s
-import instana.propagator as tp
 
 from basictracer.context import SpanContext
 from basictracer.span import BasicSpan
+from instana.http_propagator import HTTPPropagator
+from instana.text_propagator import TextPropagator
 from instana.util import generate_id
 
 # In case a user or app creates multiple tracers, we limit to just
@@ -29,7 +30,8 @@ def __init__(self, options=o.Options()):
         super(InstanaTracer, self).__init__(
             r.InstanaRecorder(self.sensor), r.InstanaSampler())
 
-        self._propagators[ot.Format.HTTP_HEADERS] = tp.HTTPPropagator()
+        self._propagators[ot.Format.HTTP_HEADERS] = HTTPPropagator()
+        self._propagators[ot.Format.TEXT_MAP] = TextPropagator()
 
     def start_span(
             self,