Improve error reporting and choose correct profiler for middleware

joerick · Apr 7, 2014 · 69e0d9d · 69e0d9d
1 parent 2edc0f4
commit 69e0d9d
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Showing 2 changed files with 15 additions and 5 deletions.
diff --git a/pyinstrument/middleware.py b/pyinstrument/middleware.py
@@ -1,8 +1,7 @@
-import os
 from django.http import HttpResponse
 from django.conf import settings
-from pyinstrument import Profiler
-from pyinstrument.stat_profiler import NotMainThreadError
+from pyinstrument import StatProfiler, EventProfiler
+from pyinstrument.stat_profiler import NotMainThreadError, SignalUnavailableError
 
 not_main_thread_message = (
     'pyinstrument can only be used on the main thread. Run your server process in single-threaded '
@@ -16,7 +15,11 @@ def __init__(self):
 
     def process_request(self, request):
         if getattr(settings, 'PYINSTRUMENT_URL_ARGUMENT', 'profile') in request.GET:
-            self.profiler = Profiler()
+            try:
+                self.profiler = StatProfiler()
+            except SignalUnavailableError:
+                self.profiler = EventProfiler()
+
             try:
                 self.profiler.start()
             except NotMainThreadError:

diff --git a/pyinstrument/stat_profiler.py b/pyinstrument/stat_profiler.py
@@ -12,12 +12,19 @@ def __init__(self, message=''):
         super(NotMainThreadError, self).__init__(message or NotMainThreadError.__doc__)
 
 
+class SignalUnavailableError(Exception):
+    '''pyinstrument.StatProfiler uses signal.SIGALRM, which is not available on your system.
+    Consider using pyinstrument.EventProfiler instead.'''
+    def __init__(self, message=''):
+        super(SignalUnavailableError, self).__init__(message or SignalUnavailableError.__doc__)
+
+
 class StatProfiler(BaseProfiler):
     def __init__(self, *args, **kwargs):
         try:
             signal.SIGALRM
         except AttributeError:
-            raise AttributeError('pyinstrument.StatProfiler uses signal.SIGALRM, which is not available on your system. Consider using pyinstrument.EventProfiler instead.')
+            raise SignalUnavailableError()
 
         self.next_profile_time = 0
         self.interval = 0.001