Collect metrics even if the request handler function raises an except…

…ion - Fixes #1

prometheus_flask_exporter/__init__.py

@@ -5,6 +5,7 @@
 
 from flask import request, make_response
 from flask import Flask, Response
+from werkzeug.exceptions import HTTPException
 from prometheus_client import Counter, Histogram, Gauge, Summary
 from prometheus_client import generate_latest, CONTENT_TYPE_LATEST
 from prometheus_client import REGISTRY as DEFAULT_REGISTRY
@@ -315,7 +316,13 @@ def func(*args, **kwargs):
                     metric = None
 
                 start_time = default_timer()
-                response = f(*args, **kwargs)
+                try:
+                    response = f(*args, **kwargs)
+                except HTTPException as ex:
+                    response = ex
+                except Exception as ex:
+                    response = make_response('Exception: %s' % ex, 500)
+
                 total_time = max(default_timer() - start_time, 0)
 
                 if not metric:
@@ -407,4 +414,4 @@ def info(self, name, description, labelnames=None, labelvalues=None, **labels):
         return gauge
 
 
-__version__ = '0.1.1'
+__version__ = '0.1.2'

setup.py

@@ -8,14 +8,14 @@
 setup(
     name='prometheus_flask_exporter',
     packages=['prometheus_flask_exporter'],
-    version='0.1.1',
+    version='0.1.2',
     description='Prometheus metrics exporter for Flask',
     long_description=long_description,
     license='MIT',
     author='Viktor Adam',
     author_email='rycus86@gmail.com',
     url='https://github.com/rycus86/prometheus_flask_exporter',
-    download_url='https://github.com/rycus86/prometheus_flask_exporter/archive/0.1.1.tar.gz',
+    download_url='https://github.com/rycus86/prometheus_flask_exporter/archive/0.1.2.tar.gz',
     keywords=['prometheus', 'flask', 'monitoring', 'exporter'],
     classifiers=[
         'Development Status :: 4 - Beta',

tests/test_endpoint.py

@@ -1,17 +1,18 @@
 from unittest_helper import BaseTestCase
+from flask import request, abort
 
 import time
 
 try:
     from urllib2 import urlopen
-except:
+except ImportError:
     # Python 3
     from urllib.request import urlopen
 
 
 class EndpointTest(BaseTestCase):
     def test_restricted(self):
-        metrics = self.metrics()
+        self.metrics()
 
         @self.app.route('/test')
         def test():
@@ -48,7 +49,7 @@ def test_http_server(self):
         metrics.start_http_server(32001)
         metrics.start_http_server(32002, endpoint='/test/metrics')
         metrics.start_http_server(32003, host='127.0.0.1')
-        
+
         def wait_for_startup():
             for _ in range(10):
                 try:
@@ -76,3 +77,55 @@ def wait_for_startup():
         self.assertEqual(response.getcode(), 200)
         self.assertIn('flask_exporter_info', str(response.read()))
 
+    def test_abort(self):
+        metrics = self.metrics()
+
+        @self.app.route('/error')
+        @metrics.summary('http_index_requests_by_status',
+                         'Request latencies by status',
+                         labels={'status': lambda r: r.status_code})
+        @metrics.histogram('http_index_requests_by_status_and_path',
+                           'Index requests latencies by status and path',
+                           labels={
+                               'status': lambda r: r.status_code,
+                               'path': lambda: request.path
+                           })
+        def throw_error():
+            return abort(503)
+
+        self.client.get('/error')
+
+        self.assertMetric('http_index_requests_by_status_count', 1.0, ('status', 503))
+        self.assertMetric('http_index_requests_by_status_sum', '.', ('status', 503))
+
+        self.assertMetric(
+            'http_index_requests_by_status_and_path_count', 1.0,
+            ('status', 503), ('path', '/error')
+        )
+        self.assertMetric(
+            'http_index_requests_by_status_and_path_sum', '.',
+            ('status', 503), ('path', '/error')
+        )
+        self.assertMetric(
+            'http_index_requests_by_status_and_path_bucket', 1.0,
+            ('status', 503), ('path', '/error'), ('le', 0.5)
+        )
+        self.assertMetric(
+            'http_index_requests_by_status_and_path_bucket', 1.0,
+            ('status', 503), ('path', '/error'), ('le', 10.0)
+        )
+
+    def test_exception(self):
+        metrics = self.metrics()
+
+        @self.app.route('/exception')
+        @metrics.summary('http_with_exception',
+                         'Tracks the method raising an exception',
+                         labels={'status': lambda r: r.status_code})
+        def raise_exception():
+            raise NotImplementedError('On purpose')
+
+        self.client.get('/exception')
+
+        self.assertMetric('http_with_exception_count', 1.0, ('status', 500))
+        self.assertMetric('http_with_exception_sum', '.', ('status', 500))