async def data_subscribe(session: BaseSession, stream: Union[DataStream, str,
int]) -> Pipe:
# make sure the input is compatible
src_stream = await data_stream_get(session, stream)
if type(stream) is DataStream:
if src_stream.layout != src_stream.layout:
raise errors.ApiError(
"Input [%s] configured for [%s] but source is [%s]" %
(stream, stream.layout, src_stream.layout))
# make sure the stream is being produced
if not src_stream.is_destination:
raise errors.ApiError(
"DataStream [%s] is not being produced, specify time bounds for historic execution"
% src_stream.name)
# replace the stub stream (from config file) with actual stream
# do not let the buffer grow beyond 5 server chunks
pipe = LocalPipe(src_stream.layout,
name=src_stream.name,
stream=src_stream,
write_limit=5)
pipe.stream = src_stream
task = asyncio.create_task(_live_reader(session, src_stream, pipe))
async def close():
task.cancel()
try:
await task
except asyncio.CancelledError:
pass
pipe.close_cb = close
return pipe
async def data_read(session: BaseSession,
stream: Union[DataStream, str, int],
start: Optional[int] = None,
end: Optional[int] = None,
max_rows: Optional[int] = None) -> Pipe:
# make sure the input is compatible
src_stream = await data_stream_get(session, stream)
if type(stream) is DataStream:
if src_stream.layout != src_stream.layout:
raise errors.ApiError(
"Input [%s] configured for [%s] but source is [%s]" %
(stream, stream.layout, src_stream.layout))
# replace the stub stream (from config file) with actual stream
pipe = LocalPipe(src_stream.layout,
name=src_stream.name,
stream=src_stream,
write_limit=5)
pipe.stream = src_stream
task = asyncio.create_task(
_historic_reader(session, src_stream, pipe, start, end, max_rows))
async def close():
task.cancel()
try:
await task
except asyncio.CancelledError:
pass
pipe.close_cb = close
return pipe