class KronosSource(DataAccess):
def __init__(self,
source,
stream=None,
start_time=None,
end_time=None,
**kwargs):
self._config = app.config['DATA_SOURCES'][source]
self._host = self._config['url']
self._namespace = self._config['namespace']
self._kronos_client = KronosClient(self._host,
namespace=self._namespace)
self.type = Operator.Type.DATA_ACCESS
self.source = source
self.stream = stream
self.start_time = start_time
self.end_time = end_time
super(KronosSource, self).__init__(**kwargs)
@classmethod
def parse(cls, _dict):
kronos_source = KronosSource(**_dict)
# TODO(usmanm): Improve validation.
assert isinstance(kronos_source._config, types.DictType)
assert isinstance(kronos_source._host, types.StringTypes)
assert isinstance(kronos_source._namespace, types.StringTypes)
assert isinstance(kronos_source.source, types.StringTypes)
assert (kronos_source.stream is None
or isinstance(kronos_source.stream, types.StringTypes))
assert (kronos_source.start_time is None
or isinstance(kronos_source.start_time, int))
assert (kronos_source.end_time is None
or isinstance(kronos_source.end_time, int))
return kronos_source
def get_streams(self):
kstreams = self._kronos_client.get_streams()
return sorted(kstreams)
def get_schema(self, stream_name):
schema = self._kronos_client.infer_schema(stream_name)
return schema
class KronosSource(DataAccess):
def __init__(self, source, stream=None, start_time=None, end_time=None,
**kwargs):
self._config = app.config['DATA_SOURCES'][source]
self._host = self._config['url']
self._namespace = self._config['namespace']
self._kronos_client = KronosClient(self._host, namespace=self._namespace)
self.type = Operator.Type.DATA_ACCESS
self.source = source
self.stream = stream
self.start_time = start_time
self.end_time = end_time
super(KronosSource, self).__init__(**kwargs)
@classmethod
def parse(cls, _dict):
kronos_source = KronosSource(**_dict)
# TODO(usmanm): Improve validation.
assert isinstance(kronos_source._config, types.DictType)
assert isinstance(kronos_source._host, types.StringTypes)
assert isinstance(kronos_source._namespace, types.StringTypes)
assert isinstance(kronos_source.source, types.StringTypes)
assert (kronos_source.stream is None or
isinstance(kronos_source.stream, types.StringTypes))
assert (kronos_source.start_time is None or
isinstance(kronos_source.start_time, int))
assert (kronos_source.end_time is None or
isinstance(kronos_source.end_time, int))
return kronos_source
def get_streams(self):
kstreams = self._kronos_client.get_streams()
return sorted(kstreams)
def get_schema(self, stream_name):
schema = self._kronos_client.infer_schema(stream_name)
return schema
"""
## Getting A List Of Streams
To see all streams available in this namespace, use `get_streams`.
"""
for stream in kc.get_streams():
print 'Found stream', stream
"""
## Inferred Schema
You can retrieve a schema for a stream. The schema is inferred from the
structure of the individual events. The schema protocol is based on JSON Schema
v4.
"""
response = kc.infer_schema('yourproduct.website.clicks')
print response['schema']
"""
## Deleting Events
Sometimes, we make an oopsie and need to delete some events. The
`delete` function takes similar arguments for the start and end
timestamps to delete.
Note: The most common Kronos use cases are for write-mostly systems
with high-throughput reads. As such, you can imagine that most
backends will not be delete-optimized. There's nothing in the Kronos
API that inherently makes deletes not performant, but we imagine some
backends will make tradeoffs to optimize their write and read paths at
the expense of fast deletes.
"""
