from __future__ import absolute_import, unicode_literals
import sys
from unittest import TestCase
from wsgiref.util import setup_testing_defaults
from prometheus_client import make_wsgi_app
from prometheus_client import CollectorRegistry, Counter, generate_latest
from prometheus_client.exposition import CONTENT_TYPE_LATEST
class WSGITest(TestCase):
def setUp(self):
self.registry = CollectorRegistry()
self.captured_status = None
self.captured_headers = None
# Setup WSGI environment
self.environ = {}
setup_testing_defaults(self.environ)
def capture(self, status, header):
self.captured_status = status
self.captured_headers = header
def assertIn(self, item, iterable):
try:
super().assertIn(item, iterable)
except: # Python < 2.7
self.assertTrue(
item in iterable,
msg="{item} not found in {iterable}".format(
item=item, iterable=iterable
)
)
def validate_metrics(self, metric_name, help_text, increments):
"""
WSGI app serves the metrics from the provided registry.
"""
c = Counter(metric_name, help_text, registry=self.registry)
for _ in range(increments):
c.inc()
# Create and run WSGI app
app = make_wsgi_app(self.registry)
outputs = app(self.environ, self.capture)
# Assert outputs
self.assertEqual(len(outputs), 1)
output = outputs[0].decode('utf8')
# Status code
self.assertEqual(self.captured_status, "200 OK")
# Headers
self.assertEqual(len(self.captured_headers), 1)
self.assertEqual(self.captured_headers[0], ("Content-Type", CONTENT_TYPE_LATEST))
# Body
self.assertIn("# HELP " + metric_name + "_total " + help_text + "\n", output)
self.assertIn("# TYPE " + metric_name + "_total counter\n", output)
self.assertIn(metric_name + "_total " + str(increments) + ".0\n", output)
def test_report_metrics_1(self):
self.validate_metrics("counter", "A counter", 2)
def test_report_metrics_2(self):
self.validate_metrics("counter", "Another counter", 3)
def test_report_metrics_3(self):
self.validate_metrics("requests", "Number of requests", 5)
def test_report_metrics_4(self):
self.validate_metrics("failed_requests", "Number of failed requests", 7)
