Improved JSON encoding, Kind handling & SDK span support (#132)

* Lowercase keys in json encoding

* Add note explaining why these fields are capitalized

* Better SDKSpan building

* Add tests for k field

* Remove unused imports

Author: pglombardo

instana/agent.py

@@ -51,11 +51,11 @@ def start(self, e):
 
     def to_json(self, o):
         def extractor(o):
-            return {k: v for k, v in o.__dict__.items() if v is not None}
+            return {k.lower(): v for k, v in o.__dict__.items() if v is not None}
 
         try:
             return json.dumps(o, default=extractor, sort_keys=False, separators=(',', ':')).encode()
-        except Exception as e:
+        except:
             logger.debug("to_json", exc_info=True)
 
     def is_timed_out(self):

instana/json_span.py

@@ -122,9 +122,13 @@ def __init__(self, **kwds):
 
 class SDKData(object):
     name = None
+
+    # Since 'type' and 'return' are a Python builtin and a reserved keyword respectively, these keys (all keys) are
+    # lower-case'd in json encoding.  See Agent.to_json
     Type = None
-    arguments = None
     Return = None
+
+    arguments = None
     custom = None
 
     def __init__(self, **kwds):

instana/recorder.py

@@ -33,6 +33,7 @@ class InstanaRecorder(SpanRecorder):
 
     entry_kind = ["entry", "server", "consumer"]
     exit_kind = ["exit", "client", "producer"]
+
     queue = queue.Queue()
 
     def __init__(self):
@@ -208,11 +209,16 @@ def build_sdk_span(self, span):
                                  logs=self.collect_logs(span))
 
         sdk_data = SDKData(name=span.operation_name,
-                           custom=custom_data)
+                           custom=custom_data,
+                           Type=self.get_span_kind_as_string(span))
+
+        if "arguments" in span.tags:
+            sdk_data.arguments = span.tags["arguments"]
 
-        sdk_data.Type = self.get_span_kind(span)
-        data = Data(service=instana.singletons.agent.sensor.options.service_name,
-                    sdk=sdk_data)
+        if "return" in span.tags:
+            sdk_data.Return = span.tags["return"]
+
+        data = Data(service=instana.singletons.agent.sensor.options.service_name, sdk=sdk_data)
         entity_from = {'e': instana.singletons.agent.from_.pid,
                       'h': instana.singletons.agent.from_.agentUuid}
 
@@ -222,6 +228,7 @@ def build_sdk_span(self, span):
                              s=span.context.span_id,
                              ts=int(round(span.start_time * 1000)),
                              d=int(round(span.duration * 1000)),
+                             k=self.get_span_kind_as_int(span),
                              n="sdk",
                              f=entity_from,
                              data=data)
@@ -246,16 +253,40 @@ def get_http_host_name(self, span):
 
         return "localhost"
 
-    def get_span_kind(self, span):
-        kind = ""
+    def get_span_kind_as_string(self, span):
+        """
+            Will retrieve the `span.kind` tag and return the appropriate string value for the Instana backend or
+            None if the tag is set to something we don't recognize.
+
+        :param span: The span to search for the `span.kind` tag
+        :return: String
+        """
+        kind = None
         if "span.kind" in span.tags:
             if span.tags["span.kind"] in self.entry_kind:
                 kind = "entry"
             elif span.tags["span.kind"] in self.exit_kind:
                 kind = "exit"
             else:
                 kind = "intermediate"
+        return kind
 
+    def get_span_kind_as_int(self, span):
+        """
+            Will retrieve the `span.kind` tag and return the appropriate integer value for the Instana backend or
+            None if the tag is set to something we don't recognize.
+
+        :param span: The span to search for the `span.kind` tag
+        :return: Integer
+        """
+        kind = None
+        if "span.kind" in span.tags:
+            if span.tags["span.kind"] in self.entry_kind:
+                kind = 1
+            elif span.tags["span.kind"] in self.exit_kind:
+                kind = 2
+            else:
+                kind = 3
         return kind
 
     def collect_logs(self, span):

tests/test_ot_span.py

@@ -128,3 +128,18 @@ def test_span_kind(self):
 
         span = spans[4]
         assert_equals('intermediate', span.data.sdk.Type)
+
+        span = spans[0]
+        assert_equals(1, span.k)
+
+        span = spans[1]
+        assert_equals(1, span.k)
+
+        span = spans[2]
+        assert_equals(2, span.k)
+
+        span = spans[3]
+        assert_equals(2, span.k)
+
+        span = spans[4]
+        assert_equals(3, span.k)

tests/test_ot_tracer.py

@@ -1,7 +1,4 @@
 import opentracing
-from nose.tools import assert_equals
-
-from instana.singletons import tracer
 
 
 def test_tracer_basics():