def test_create_key():
with pytest.raises(TypeError):
create_key(['un', 'hashable'], 'this should raise')
assert create_key('get schwifty',
'ztm') == 'tscached:ztm:6fed3992d23c711d8c21d354f6dc46e9'
assert create_key(json.dumps(
{}), 'lulz') == 'tscached:lulz:99914b932bd37a50b983c5e7c90ae93b'
def metadata_caching(config, name, endpoint, post_data=None):
""" Encapsulate stupid-simple cache logic for Kairos "metadata" endpoints.
config: nested dict loaded from the 'tscached' section of a yaml file.
name: string, used as a part of redis keying.
endpoint: string, the corresponding kairosdb endpoint.
post_data: None or string. overrides default GET proxy behavior. implies custom keying.
returns: 2-tuple: (content, HTTP code)
"""
if post_data:
redis_key = create_key(post_data, name)
else:
redis_key = 'tscached:' + name
redis_client = redis.StrictRedis(host=config['redis']['host'], port=config['redis']['port'])
try:
get_result = redis_client.get(redis_key)
except redis.exceptions.RedisError as e:
logging.error('RedisError: ' + e.message)
get_result = False # proxy through to kairos even if redis is broken
if get_result: # hit. no need to process the JSON blob, so don't!
logging.info('Meta Endpoint HIT: %s' % redis_key)
return get_result, 200
else:
logging.info('Meta Endpoint MISS: %s' % redis_key)
url = 'http://%s:%s%s' % (config['kairosdb']['host'], config['kairosdb']['port'], endpoint)
try:
if post_data:
kairos_result = requests.post(url, data=post_data)
else:
kairos_result = requests.get(url)
except requests.exceptions.RequestException as e:
logging.error('BackendQueryFailure: %s' % e.message)
return json.dumps({'error': 'Could not connect to KairosDB: %s' % e.message}), 500
if kairos_result.status_code / 100 != 2:
# propagate the kairos message to the user along with its error code.
value = json.loads(kairos_result.text)
value_message = ', '.join(value.get('errors', ['No message given']))
message = 'Meta Endpoint: %s: KairosDB responded %d: %s' % (redis_key,
kairos_result.status_code,
value_message)
return json.dumps({'error': message}), 500
else:
# kairos response seems to be okay
expiry = config['expiry'].get(name, 300) # 5 minute default
try:
set_result = redis_client.set(redis_key, kairos_result.text, ex=expiry)
if not set_result:
logging.error('Meta Endpoint: %s: Cache SET failed: %s' % (redis_key, set_result))
except redis.exceptions.RedisError as e:
# Eat the Redis exception - turns these endpoints into straight proxies.
logging.error('RedisError: ' + e.message)
return kairos_result.text, kairos_result.status_code, {'Content-Type': 'application/json'}
def test_create_key():
with pytest.raises(TypeError):
create_key(['un', 'hashable'], 'this should raise')
assert create_key('get schwifty', 'ztm') == 'tscached:ztm:6fed3992d23c711d8c21d354f6dc46e9'
assert create_key(json.dumps({}), 'lulz') == 'tscached:lulz:99914b932bd37a50b983c5e7c90ae93b'
