[ci-visibility] Fix Unicode Serialization for Exceptions (DataDog#3016)

* serialize using six

* add test

* test unicode in py2

* Update ddtrace/span.py

Co-authored-by: Brett Langdon <brett.langdon@datadoghq.com>

* Apply suggestions from code review

Co-authored-by: Gabriele N. Tornetta <P403n1x87@users.noreply.github.com>

* fix test

* fix encoding

* fix tests again

* use exception message

* Update ddtrace/span.py

Co-authored-by: Gabriele N. Tornetta <P403n1x87@users.noreply.github.com>

* Update ddtrace/span.py

Co-authored-by: Gabriele N. Tornetta <P403n1x87@users.noreply.github.com>

* Update ddtrace/span.py

Co-authored-by: Gabriele N. Tornetta <P403n1x87@users.noreply.github.com>

* clean up args

* handle condition in python2 where the exception message is not unicode

* convert span.meta.error.msg to unicode

* stringify and skip the test case where non ascii character exists in a uft8 encoded string in python2

* Update test_span.py

* Update test_span.py

* fix test

* Update test_span.py

Co-authored-by: Brett Langdon <brett.langdon@datadoghq.com>
Co-authored-by: Gabriele N. Tornetta <P403n1x87@users.noreply.github.com>
Co-authored-by: Munir Abdinur <munir.abdinur@datadoghq.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Author: 5 people

ddtrace/span.py

@@ -478,7 +478,7 @@ def set_exc_info(self, exc_type, exc_val, exc_tb):
         # readable version of type (e.g. exceptions.ZeroDivisionError)
         exc_type_str = "%s.%s" % (exc_type.__module__, exc_type.__name__)
 
-        self.meta[ERROR_MSG] = str(exc_val)
+        self.meta[ERROR_MSG] = stringify(exc_val)
         self.meta[ERROR_TYPE] = exc_type_str
         self.meta[ERROR_STACK] = tb
 

tests/tracer/test_span.py

@@ -676,3 +676,21 @@ def test_manual_context_usage():
     span1.context.sampling_priority = 1
     assert span2.context.sampling_priority == 1
     assert span1.context.sampling_priority == 1
+
+
+def test_set_exc_info_with_unicode():
+    def get_exception_span(exception):
+        span = Span(None, "span1")
+        try:
+            raise exception
+        except Exception:
+            type_, value_, traceback_ = sys.exc_info()
+            span.set_exc_info(type_, value_, traceback_)
+        return span
+
+    exception_span = get_exception_span(Exception(u"DataDog/水"))
+    assert u"DataDog/水" == exception_span.get_tag(ERROR_MSG)
+
+    if six.PY3:
+        exception_span = get_exception_span(Exception("DataDog/水"))
+        assert "DataDog/水" == exception_span.get_tag(ERROR_MSG)