Add a Slack logging features

Handler, Formatter and Filter

setup.py

@@ -23,7 +23,9 @@
     package_dir={'webhook_logger':
                  'webhook_logger'},
     include_package_data=True,
-    install_requires=[],
+    install_requires=[
+        'requests',
+    ],
     license="MIT license",
     zip_safe=False,
     keywords='webhook_logger',
@@ -41,5 +43,8 @@
         'Programming Language :: Python :: 3.5',
     ],
     test_suite='tests',
-    tests_require=[]
+    tests_require=[
+        'requests_mock',
+        'mock'
+    ]
 )

tests/test_slack.py

@@ -0,0 +1,45 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+import logging
+import unittest
+
+import mock
+import requests_mock
+
+from webhook_logger.slack import SlackHandler
+
+
+class TestSlackLogger(unittest.TestCase):
+    def setUp(self):
+        self.rm = requests_mock.mock()
+        self.rm.start()
+
+    def tearDown(self):
+        self.rm.stop()
+
+    def _build_logger(self, name, url=None):
+        logger = logging.getLogger(name)
+        logger.setLevel(logging.INFO)
+        h = SlackHandler(hook_url=url)
+        h.setLevel(logging.INFO)
+        logger.addHandler(h)
+        return logger
+
+    def test_incorrect_config(self):
+        logger = self._build_logger('incorrect')
+        logger.info("test", extra={'notify_slack': True})
+        self.assertEqual(self.rm.call_count, 0)
+
+    def test_correct_config(self):
+        self.rm.post('https://some-hook.com/abcde', json={'message': "OK"})
+        logger = self._build_logger('basic', 'https://some-hook.com/abcde')
+        logger.info("test", extra={'notify_slack': True})
+        self.assertEqual(self.rm.call_count, 1)
+
+    @mock.patch('webhook_logger.slack.settings')
+    def test_django_config(self, settings):
+        settings.SLACK_WEBHOOK_URL = 'https://some-hook.com/abcde'
+        self.rm.post('https://some-hook.com/abcde', json={'message': "OK"})
+        logger = self._build_logger('django')
+        logger.info("Test", extra={'notify_slack': True})
+        self.assertEqual(self.rm.call_count, 1)

webhook_logger/slack.py

@@ -0,0 +1,83 @@
+# -*- coding: utf-8
+from __future__ import unicode_literals, absolute_import
+
+import json
+import logging
+
+import requests
+try:
+    from django.conf import settings
+except ImportError:
+    settings = None
+
+logger = logging.getLogger(__name__)
+
+
+class SlackHandler(logging.Handler):
+    """Logging handler to post to Slack to the webhook URL"""
+    def __init__(self, hook_url=None, *args, **kwargs):
+        super(SlackHandler, self).__init__(*args, **kwargs)
+        self._hook_url = hook_url
+        self.formatter = SlackFormatter()
+
+    @property
+    def hook_url(self):
+        if self._hook_url is None:
+            self._hook_url = getattr(settings, 'SLACK_WEBHOOK_URL', '')
+        return self._hook_url
+
+    def emit(self, record):
+        """
+        Submit the record with a POST request
+        """
+        try:
+            slack_data = self.format(record)
+            requests.post(
+                self.hook_url, data=slack_data,
+                headers={'Content-Type': 'application/json'}
+            )
+        except Exception:
+            self.handleError(record)
+
+    def filter(self, record):
+        """
+        Disable the logger if hook_url isn't defined,
+        we don't want to do it in all environments (e.g local/CI)
+        """
+        if not self.hook_url:
+            return 0
+        return super(SlackHandler, self).filter(record)
+
+
+class SlackLogFilter(logging.Filter):
+    """
+    Logging filter to decide when logging to Slack is requested, using
+    the `extra` kwargs:
+
+        `logger.info("...", extra={'notify_slack': True})`
+    """
+    def filter(self, record):
+        return getattr(record, 'notify_slack', False)
+
+
+class SlackFormatter(logging.Formatter):
+    def format(self, record):
+        """
+        Format message content, timestamp when it was logged and a
+        coloured border depending on the severity of the message
+        """
+        ret = {
+            'ts': record.created,
+            'text': record.getMessage(),
+        }
+        try:
+            loglevel_colour = {
+                'INFO': 'good',
+                'WARNING': 'warning',
+                'ERROR': '#E91E63',
+                'CRITICAL': 'danger',
+            }
+            ret['color'] = loglevel_colour[record.levelname]
+        except KeyError:
+            pass
+        return json.dumps({'attachments': [ret]})