Unify Django middleware into one; Update hooks

Author: pglombardo

instana/django.py

@@ -1,20 +1,26 @@
 from __future__ import print_function
 import opentracing as ot
 from instana import internal_tracer
+from instana.log import logger
 import opentracing.ext.tags as ext
 import os
 
 
 DJ_INSTANA_MIDDLEWARE = 'instana.django.InstanaMiddleware'
 
+try:
+    from django.utils.deprecation import MiddlewareMixin
+except ImportError:
+    MiddlewareMixin = object
 
-class InstanaMiddleware(object):
+
+class InstanaMiddleware(MiddlewareMixin):
     """ Django Middleware to provide request tracing for Instana """
-    def __init__(self, get_response):
+    def __init__(self, get_response=None):
         self.get_response = get_response
         self
 
-    def __call__(self, request):
+    def process_request(self, request):
         env = request.environ
         if 'HTTP_X_INSTANA_T' in env and 'HTTP_X_INSTANA_S' in env:
             ctx = internal_tracer.extract(ot.Format.HTTP_HEADERS, env)
@@ -26,22 +32,39 @@ def __call__(self, request):
         span.set_tag("http.params", env['QUERY_STRING'])
         span.set_tag(ext.HTTP_METHOD, request.method)
         span.set_tag("http.host", env['HTTP_HOST'])
+        self.span = span
 
-        response = self.get_response(request)
-
-        if 500 <= response.status_code <= 511:
-            span.set_tag("error", True)
-            ec = span.tags.get('ec', 0)
-            span.set_tag("ec", ec+1)
+    def process_response(self, request, response):
+        if self.span:
+            if 500 <= response.status_code <= 511:
+                self.span.set_tag("error", True)
+                ec = self.span.tags.get('ec', 0)
+                if ec is 0:
+                    self.span.set_tag("ec", ec+1)
 
-        span.set_tag(ext.HTTP_STATUS_CODE, response.status_code)
-        internal_tracer.inject(span.context, ot.Format.HTTP_HEADERS, response)
-        span.finish()
+            self.span.set_tag(ext.HTTP_STATUS_CODE, response.status_code)
+            internal_tracer.inject(self.span.context, ot.Format.HTTP_HEADERS, response)
+            self.span.finish()
+            self.span = None
         return response
 
+    def process_exception(self, request, exception):
+        logger.warn("process exception")
+        if self.span:
+            self.span.log_kv({'message': exception})
+            self.span.set_tag("error", True)
+            ec = self.span.tags.get('ec', 0)
+            self.span.set_tag("ec", ec+1)
+
+    # def process_template_response(self, request, response):
+    #     logger.warn("process template response")
+    #
+    # def process_view(self, request, view_func, view_args, view_kwargs):
+    #     logger.warn("process_view %s %s %s %s", request, view_func, view_args, view_kwargs)
+
 
 def hook(module):
-    """ Hook method to install the Instana middleware into Django """
+    """ Hook method to install the Instana middleware into Django >= 1.10 """
     if "INSTANA_DEV" in os.environ:
         print("==============================================================")
         print("Instana: Running django hook")
@@ -58,3 +81,21 @@ def hook(module):
                 DJ_INSTANA_MIDDLEWARE] + module.settings.MIDDLEWARE
     else:
         print("Instana: Couldn't add InstanaMiddleware to Django")
+
+
+def hook19(module):
+    """ Hook method to install the Instana middleware into Django <= 1.9 """
+    if "INSTANA_DEV" in os.environ:
+        print("==============================================================")
+        print("Instana: Running django19 hook")
+        print("==============================================================")
+
+    if DJ_INSTANA_MIDDLEWARE in module.settings.MIDDLEWARE_CLASSES:
+        return
+
+    if type(module.settings.MIDDLEWARE_CLASSES) is tuple:
+        module.settings.MIDDLEWARE_CLASSES = (DJ_INSTANA_MIDDLEWARE,) + module.settings.MIDDLEWARE_CLASSES
+    elif type(module.settings.MIDDLEWARE_CLASSES) is list:
+        module.settings.MIDDLEWARE_CLASSES = [DJ_INSTANA_MIDDLEWARE] + module.settings.MIDDLEWARE_CLASSES
+    else:
+        print("Instana: Couldn't add InstanaMiddleware to Django")

instana/django19.py

@@ -17,7 +17,7 @@
                         'opentracing>=1.2.1,<1.3',
                         'basictracer>=2.2.0'],
       entry_points={'django': ['django.core.handlers.base = instana.django:hook'],
-                    'django19': ['django.core.handlers.base = instana.django19:hook'],
+                    'django19': ['django.core.handlers.base = instana.django:hook19'],
                     'flask': ['flask = instana.flaskana:hook'],
                     'runtime': ['string = instana.runtime:hook']},
       test_suite='nose.collector',