Fix B3Codec's trace_id zero-padding for 32bit IDs (#322)

* fix B3Codec inject bug for traceid

Signed-off-by: mizhexiaoxiao <[email protected]>

* add unit test

Signed-off-by: mizhexiaoxiao <[email protected]>

* format

Signed-off-by: mizhexiaoxiao <[email protected]>

* make lint

Signed-off-by: mizhexiaoxiao <[email protected]>

Author: mizhexiaoxiao

jaeger_client/codecs.py

@@ -334,10 +334,16 @@ class B3Codec(Codec):
     flags_header = 'X-B3-Flags'
     _flags_header_lc = flags_header.lower()
 
+    def __init__(self, generate_128bit_trace_id=False):
+        self.generate_128bit_trace_id = generate_128bit_trace_id
+
     def inject(self, span_context, carrier):
         if not isinstance(carrier, dict):
             raise InvalidCarrierException('carrier not a dictionary')
-        carrier[self.trace_header] = format(span_context.trace_id, 'x').zfill(16)
+        if self.generate_128bit_trace_id:
+            carrier[self.trace_header] = format(span_context.trace_id, 'x').zfill(32)
+        else:
+            carrier[self.trace_header] = format(span_context.trace_id, 'x').zfill(16)
         carrier[self.span_header] = format(span_context.span_id, 'x').zfill(16)
         if span_context.parent_id is not None:
             carrier[self.parent_span_header] = format(span_context.parent_id, 'x').zfill(16)

jaeger_client/config.py

@@ -314,7 +314,9 @@ def propagation(self):
         propagation = self.config.get('propagation')
         if propagation == 'b3':
             # replace the codec with a B3 enabled instance
-            return {Format.HTTP_HEADERS: B3Codec()}
+            return {Format.HTTP_HEADERS: B3Codec(
+                generate_128bit_trace_id=self.generate_128bit_trace_id
+            )}
         return {}
 
     def throttler_group(self):

tests/test_codecs.py

@@ -376,6 +376,17 @@ def test_zipkin_b3_codec_extract_injected(self):
         assert extracted.parent_id == ctx.parent_id
         assert extracted.flags == ctx.flags
 
+    def test_128bit_trace_id_with_zero_padding(self):
+        codec = B3Codec(generate_128bit_trace_id=True)
+
+        carrier_1 = {'X-B3-SpanId': '39fe73de0012a0e5', 'X-B3-ParentSpanId': '3dbf8a511e159b05',
+                     'X-B3-TraceId': '023f352eaefd8b887a06732f5312e2de', 'X-B3-Flags': '0'}
+        span_context = codec.extract(carrier_1)
+
+        carrier_2 = {}
+        codec.inject(span_context=span_context, carrier=carrier_2)
+        assert carrier_1['X-B3-TraceId'] == carrier_2['X-B3-TraceId']
+
     def test_binary_codec(self):
         codec = BinaryCodec()
         with self.assertRaises(InvalidCarrierException):