Merge pull request #50317 from mitodl/sar/http_beacon

Beacon to check on status endpoint

salt/beacons/http_status.py

@@ -0,0 +1,158 @@
+# -*- coding: utf-8 -*-
+'''
+Beacon to manage and report the status of a server status endpoint.
+Fire an event when specified values don't match returned response.
+
+'''
+
+# Import Python libs
+from __future__ import absolute_import, unicode_literals
+import logging
+import operator
+import re
+import requests
+import itertools
+import salt.utils.data
+from salt.ext.six.moves import map
+
+log = logging.getLogger(__name__)
+
+__virtualname__ = 'http_status'
+
+comparisons = {
+    '==': operator.eq,
+    '<': operator.lt,
+    '>': operator.gt,
+    '<=': operator.le,
+    '>=': operator.ge,
+    '!=': operator.ne,
+    'search': re.search
+}
+
+attr_func_map = {
+  'status': lambda x: x.status_code,
+  'content': lambda x: x.json()
+}
+
+required_site_attributes = {'url'}
+optional_site_attributes = {'content', 'status'}
+
+
+def __virtual__():
+    return __virtualname__
+
+
+def validate(config):
+    '''
+    Validate the beacon configuration
+    '''
+    valid = True
+    messages = []
+
+    if not isinstance(config, list):
+        valid = False
+        messages.append('[-] Configuration for %s beacon must be a list', config)
+    else:
+        _config = {}
+        list(map(_config.update, config))
+
+    try:
+        sites = _config.get('sites', {})
+    except AttributeError:
+        valid = False
+        messages.append('[-] Sites for %s beacon must be a dict', __virtualname__)
+
+    if not sites:
+        valid = False
+        messages.append('[-] Configuration does not contain sites')
+
+    for site, settings in sites.items():
+        if required_site_attributes.isdisjoint(set(settings.keys())):
+            valid = False
+            messages.append('[-] Sites for {} beacon requires {}'.format(__virtualname__,
+                                                                         required_site_attributes))
+        log.debug('[+] site: %s', site)
+        log.debug('[+] settings: %s', settings)
+
+        for optional_attrs in itertools.chain(settings.get(attr, []) for attr in optional_site_attributes):
+            for item in optional_attrs:
+                cmp = item.get('comp')
+                if cmp and cmp not in comparisons:
+                    valid = False
+                    messages.append('[-] Invalid comparison operator %s', cmp)
+
+    messages.append('[+] Valid beacon configuration')
+    return valid, messages
+
+
+def beacon(config):
+    '''
+    Check on different service status reported by the django-server-status
+    library.
+
+    .. code-block:: yaml
+
+        beacons:
+          http_status:
+            - sites:
+                example-site-1:
+                  url: "https://example.com/status"
+                  timeout: 30
+                  content-type: json
+                  status:
+                    - value: 400
+                      comp: <
+                    - value: 300
+                      comp: '>='
+                  content:
+                    - path: 'certificate:status'
+                      value: down
+                      comp: '=='
+                    - path: 'status_all'
+                      value: down
+                      comp: '=='
+            - interval: 10
+    '''
+    ret = []
+
+    _config = {}
+    list(map(_config.update, config))
+
+    for site, site_config in _config.get('sites', {}).items():
+        url = site_config.pop('url')
+        content_type = site_config.pop('content_type', 'json')
+        try:
+            r = requests.get(url, timeout=site_config.pop('timeout', 30))
+        except requests.exceptions.RequestException as e:
+            log.info("Request failed: %s", e)
+            if r.raise_for_status:
+                log.info('[-] Response from status endpoint was invalid: '
+                         '%s', r.status_code)
+                _failed = {'status_code': r.status_code,
+                           'url': url}
+                ret.append(_failed)
+                continue
+
+        for attr, checks in site_config.items():
+            for check in checks:
+                log.debug('[+] response_item: %s', attr)
+                attr_path = check.get('path', '')
+                comp = comparisons[check['comp']]
+                expected_value = check['value']
+                if attr_path:
+                    received_value = salt.utils.data.traverse_dict_and_list(attr_func_map[attr](r), attr_path)
+                else:
+                    received_value = attr_func_map[attr](r)
+                if received_value is None:
+                    log.info('[-] No data found at location {} for url {}'.format(attr_path, url))
+                    continue
+                log.debug('[+] expected_value: %s', expected_value)
+                log.debug('[+] received_value: %s', received_value)
+                if not comp(expected_value, received_value):
+                    _failed = {'expected': expected_value,
+                               'received': received_value,
+                               'url': url,
+                               'path': attr_path
+                               }
+                    ret.append(_failed)
+    return ret