From ba168711017548d2a8d342c4017b9bf9d7aa8147 Mon Sep 17 00:00:00 2001
From: Peter Giacomo Lombardo <pglombardo@gmail.com>
Date: Mon, 8 Jan 2018 19:29:03 +0100
Subject: [PATCH] Don't instrument urllib3 if it isn't present

---
 instana/instrumentation/urllib3.py | 60 ++++++++++++++++--------------
 1 file changed, 32 insertions(+), 28 deletions(-)

diff --git a/instana/instrumentation/urllib3.py b/instana/instrumentation/urllib3.py
index 9fb97ce9..1b17ef47 100644
--- a/instana/instrumentation/urllib3.py
+++ b/instana/instrumentation/urllib3.py
@@ -5,38 +5,42 @@
 import wrapt
 
 
-@wrapt.patch_function_wrapper('urllib3', 'PoolManager.urlopen')
-def urlopen_with_instana(wrapped, instance, args, kwargs):
-    context = instana.internal_tracer.current_context()
+try:
+    import urllib3
 
-    # If we're not tracing, just return
-    if context is None:
-        return wrapped(*args, **kwargs)
+    @wrapt.patch_function_wrapper('urllib3', 'PoolManager.urlopen')
+    def urlopen_with_instana(wrapped, instance, args, kwargs):
+        context = instana.internal_tracer.current_context()
 
-    try:
-        span = instana.internal_tracer.start_span("urllib3", child_of=context)
-        span.set_tag(ext.HTTP_URL, args[1])
-        span.set_tag(ext.HTTP_METHOD, args[0])
+        # If we're not tracing, just return
+        if context is None:
+            return wrapped(*args, **kwargs)
 
-        instana.internal_tracer.inject(span.context, opentracing.Format.HTTP_HEADERS, kwargs["headers"])
-        rv = wrapped(*args, **kwargs)
+        try:
+            span = instana.internal_tracer.start_span("urllib3", child_of=context)
+            span.set_tag(ext.HTTP_URL, args[1])
+            span.set_tag(ext.HTTP_METHOD, args[0])
 
-        span.set_tag(ext.HTTP_STATUS_CODE, rv.status)
-        if 500 <= rv.status <= 599:
+            instana.internal_tracer.inject(span.context, opentracing.Format.HTTP_HEADERS, kwargs["headers"])
+            rv = wrapped(*args, **kwargs)
+
+            span.set_tag(ext.HTTP_STATUS_CODE, rv.status)
+            if 500 <= rv.status <= 599:
+                span.set_tag("error", True)
+                ec = span.tags.get('ec', 0)
+                span.set_tag("ec", ec+1)
+
+        except Exception as e:
+            span.log_kv({'message': e})
             span.set_tag("error", True)
             ec = span.tags.get('ec', 0)
             span.set_tag("ec", ec+1)
-
-    except Exception as e:
-        span.log_kv({'message': e})
-        span.set_tag("error", True)
-        ec = span.tags.get('ec', 0)
-        span.set_tag("ec", ec+1)
-        span.finish()
-        raise
-    else:
-        span.finish()
-        return rv
-
-
-instana.log.debug("Instrumenting urllib3")
+            span.finish()
+            raise
+        else:
+            span.finish()
+            return rv
+
+    instana.log.debug("Instrumenting urllib3")
+except ImportError:
+    pass