Merge pull request #15 from garnertb/exception-handler

Add a SlackExceptionHandler.

django_slack/__init__.py

@@ -99,6 +99,28 @@
 please visit the `Slack API Attachments Docs
 <https://api.slack.com/docs/attachments>`_.
 
+Logging Exceptions to Slack
+---------------------------
+
+You can send logging messages from Django to Slack using the SlackExceptionHandler:
+
+#. Add a handler that uses the SlackExceptionHandler class to the LOGGING
+dictionary in your settings file::
+
+    LOGGING = {
+        'handlers': {
+            'slack_admins': {
+                'level': 'ERROR',
+                'filters': ['require_debug_false'],
+                'class': 'django_slack.logs.SlackExceptionHandler'
+            }
+        },
+        "loggers": {
+            "django": {
+                "handlers": ["console", "slack_admins"], "level": "ERROR", },
+        }
+    }
+
 Configuration
 -------------
 

django_slack/logs.py

@@ -0,0 +1,85 @@
+import copy
+import logging
+from . import slack_message
+from django.conf import settings
+from django.views.debug import ExceptionReporter
+
+
+class SlackExceptionHandler(logging.Handler):
+    """
+    An exception log handler that sends log entries to a Slack channel.
+    """
+
+    def __init__(self, **kwargs):
+        # pop any kwargs that shouldn't be passed into the Slack message attachment here.
+        self.template = kwargs.pop('template', 'django_slack/exception')
+        self.kwargs = kwargs
+        logging.Handler.__init__(self)
+
+    def emit(self, record):
+        try:
+            request = record.request
+            subject = '%s (%s IP): %s' % (
+                record.levelname,
+                ('internal' if request.META.get('REMOTE_ADDR') in settings.INTERNAL_IPS
+                 else 'EXTERNAL'),
+                record.getMessage(),
+            )
+        except Exception:
+            subject = '%s: %s' % (
+                record.levelname,
+                record.getMessage(),
+            )
+            request = None
+        subject = self.format_subject(subject)
+
+        # Since we add a nicely formatted traceback on our own, create a copy
+        # of the log record without the exception data.
+        no_exc_record = copy.copy(record)
+        no_exc_record.exc_info = None
+        no_exc_record.exc_text = None
+
+        if record.exc_info:
+            exc_info = record.exc_info
+        else:
+            exc_info = (None, record.getMessage(), None)
+
+        reporter = ExceptionReporter(request, is_email=True, *exc_info)
+        message = "%s\n\n%s" % (self.format(no_exc_record), reporter.get_traceback_text())
+
+        colors = {
+            'ERROR': 'danger',
+            'WARNING': 'warning',
+            'INFO': 'good',
+        }
+
+        attachments = {
+            'title': subject,
+            'text': message,
+            'color': colors.get(record.levelname, '#AAAAAA'),
+        }
+
+        attachments.update(self.kwargs)
+        self.send_message(self.template, {'text': subject},
+                          self.generate_attachments(**attachments))
+
+    def generate_attachments(self, **kwargs):
+        """
+        Hook to override attachments.
+        """
+        return [kwargs]
+
+    def send_message(self, *args, **kwargs):
+        """
+        Hook to update the message before sending.
+        """
+        return slack_message(*args, **kwargs)
+
+    def format_subject(self, subject):
+        """
+        Escape CR and LF characters, and limit length.
+        RFC 2822's hard limit is 998 characters per line. So, minus "Subject: "
+        the actual subject must be no longer than 989 characters.
+        """
+        formatted_subject = subject.replace('\n', '\\n').replace('\r', '\\r')
+        return formatted_subject[:989]

django_slack/templates/django_slack/exception

@@ -0,0 +1,10 @@
+{% extends django_slack %}
+
+{% comment %}
+This is the default template for the SlackExceptionHandler, which
+is intended to work out of the box without requiring user modification.
+{% endcomment %}
+
+{% block text %}
+{{ text }}
+{% endblock %}