Add type safety checking in add_trace_field, bump version

#96 added a string content check to the trace field name, but there were previously no checks to ensure that this value is in fact a string. Any customer using the beeline that picks up that patch and is using unusual types here could crash, so I added some type checking before bumping the version on this release.

CHANGELOG.md

@@ -1,5 +1,11 @@
 # beeline-python changelog
 
+## 2.11.3 2020-01-23
+
+Fixes
+
+- Prevent duplicate `app.` prefixes in trace fields. [#96](https://github.com/honeycombio/beeline-python/pull/96)
+
 ## 2.11.2 2019-11-26
 
 Fixes

beeline/test_trace.py

@@ -274,6 +274,10 @@ def test_add_trace_field_propagates(self):
 
         tracer.add_trace_field('another', 'important_thing')
         tracer.add_trace_field('wide', 'events_are_great')
+        # ensure we don't crash if non-string added here
+        tracer.add_trace_field(12345, 54321)
+        # ensure fields prefixed with app. don't get another prefix
+        tracer.add_trace_field('app.prefixes', 'there should only be 1')
 
         span2 = tracer.start_span(context={'more': 'important_stuff'})
         # should still have the root span as the first item in the stack
@@ -287,7 +291,9 @@ def test_add_trace_field_propagates(self):
         self.assertEqual(span.trace_id, tracer._trace.id)
         m_client.new_event.assert_called_once_with(data={
                 'app.another': 'important_thing',
-                'app.wide': 'events_are_great'
+                'app.wide': 'events_are_great',
+                'app.12345': 54321,
+                'app.prefixes': 'there should only be 1',
         })
         m_client.new_event.return_value.add.assert_has_calls([
             call(data={'more': 'important_stuff'}),
@@ -315,6 +321,8 @@ def test_add_trace_field_propagates(self):
         m_client.new_event.assert_called_once_with(data={
                 'app.wide': 'events_are_great',
                 'app.more': 'data!',
+                'app.12345': 54321,
+                'app.prefixes': 'there should only be 1',
         })
 
     def test_add_rollup_field_propagates(self):

beeline/trace.py

@@ -206,8 +206,12 @@ def add_rollup_field(self, name, value):
     def add_trace_field(self, name, value):
         # prefix with app to avoid key conflicts
         # add the app prefix if it's missing
-        if not name.startswith("app."):
+
+        if (type(name) == str and not name.startswith("app.")) or type(name) != str:
             key = "app.%s" % name
+        else:
+            key = name
+
         # also add to current span
         self.add_context_field(key, value)
 

beeline/version.py

@@ -1 +1 @@
-VERSION = '2.11.2'
+VERSION = '2.11.3'

setup.py

@@ -3,7 +3,7 @@
 setup(
     python_requires='>=2.7',
     name='honeycomb-beeline',
-    version='2.11.2',
+    version='2.11.3',
     description='Honeycomb library for easy instrumentation',
     url='https://github.com/honeycombio/beeline-python',
     author='Honeycomb.io',