def read_nowait(self, flatten=False):
"""
Same as read but this is not a coroutine. This should only be used for unit testing.
Args:
flatten:
Returns:
numpy.ndarray
>>> data = pipe.read_nowait()
[1, 2, 3]
"""
if self._failed:
raise PipeError('pipe failed')
# if reread is set just return the old data
if self._reread:
self._reread = False
if len(self.read_buffer) == 0:
raise PipeError("No data left to reread")
return self._format_data(self.read_buffer, flatten)
# if the queue is empty and we have old data, just return the old data
if self.queue.empty() and len(self.read_buffer) > 0:
return self._format_data(self.read_buffer, flatten)
# if the buffer is empty and the queue is empty and the pipe is closed
if self.queue.empty() and len(self.read_buffer) == 0 and self.closed:
raise EmptyPipe()
# do not wait for new data, return an empty array if nothing else is available
return self._read(flatten)
async def close_interval(self):
"""
Signal a break in the data stream. This should be used to indicate missing data.
Data returned from :meth:`read` will be chunked by interval boundaries.
"""
if self.direction == Pipe.DIRECTION.INPUT:
raise PipeError("cannot write to an input pipe")
raise PipeError("abstract method must be implemented by child")
async def flush_cache(self):
"""
Force a pipe flush even if the cache is not full. Raises an error if caching is not
enabled.
"""
if self.direction == Pipe.DIRECTION.INPUT:
raise PipeError("cannot control cache on input pipes")
raise PipeError("abstract method must be implemented by child")
async def close_interval(self):
if self._failed:
raise PipeError('pipe failed')
if self.closed:
raise PipeError("Cannot write to a closed pipe")
if self.debug:
print("[%s:write] closing interval" % self.name)
if self._caching:
await self.flush_cache()
await self.queue.put(None)
def reread_last(self):
"""
The next read will return only unconsumed data from the previous read
and no new data from the source. The end_of_interval flag is maintained.
"""
if self.direction == Pipe.DIRECTION.OUTPUT:
raise PipeError("cannot read from an output pipe")
raise PipeError("Not Implemented")
def _validate_data(data):
if type(data) is not np.ndarray:
raise PipeError("invalid data type must be a structured array or 2D matrix")
# check for valid data type
try:
if (len(data) == 0) or len(data[0]) == 0:
log.info("pipe write called with no data")
return False
except TypeError:
raise PipeError("invalid data type must be a structured array or 2D matrix")
return True
def consume(self, num_rows):
if num_rows == 0:
return # nothing to do
if num_rows < 0:
raise PipeError("consume called with negative offset: %d" %
num_rows)
if num_rows > self.last_index:
raise PipeError("cannot consume %d rows: only %d available" %
(num_rows, self.last_index))
self.buffer = np.roll(self.buffer, -1 * num_rows)
self.last_index -= num_rows
def close_nowait(self):
"""
Same as close but this is not a coroutine. This should only be used for
unit testing
"""
if len(self.subscribers) > 0:
raise PipeError("cannot close_nowait subscribers, use async")
if self.close_cb is not None:
raise PipeError("close_cb cannot be executed, use async")
self.closed = True
def consume(self, num_rows):
if num_rows == 0:
return
if num_rows < 0:
raise PipeError("consume called with negative offset: %d" %
num_rows)
if num_rows > len(self.read_buffer):
raise PipeError("cannot consume %d rows: only %d available" %
(num_rows, len(self.read_buffer)))
if self.debug:
print("[%s:read] consumed %d rows" % (self.name, num_rows))
self.read_buffer = self.read_buffer[num_rows:]
async def read_all(self, flatten=False, maxrows=1e5, error_on_overflow=False) -> np.ndarray:
"""
Read stream data. By default this method returns a structured
array with ``timestamp`` and ``data`` fields. The pipe is automatically closed.
This method is a coroutine.
Args:
flatten: return an unstructured array (flat 2D matrix) with timestamps in the first column
maxrows: the maximum number of rows to read from the pipe
error_on_overflow: raise a PipeError exception if pipe is not empty after reading maxrows
Returns:
numpy.ndarray
>>> data = await pipe.read_all(flatten=True)
[1, 2, 3]
"""
if self.direction == Pipe.DIRECTION.OUTPUT:
raise PipeError("cannot read from an output pipe")
data = None
while True:
try:
new_data = await self.read(flatten)
self.consume(len(new_data))
except PipeError:
break
if data is None:
data = new_data
if len(data) > maxrows:
await self.close()
if error_on_overflow:
raise PipeError("More than [%d] rows, increase maxrows or disable error_on_overflow" % maxrows)
return data[:maxrows]
else:
if len(data) + len(new_data) > maxrows:
await self.close()
if error_on_overflow:
raise PipeError("More than [%d] rows, increase maxrows or disable error_on_overflow" % maxrows)
remaining_rows = maxrows - len(data)
if flatten:
data = np.vstack((data, new_data[:remaining_rows]))
else:
data = np.hstack((data, new_data[:remaining_rows]))
break
if flatten:
data = np.vstack((data, new_data))
else:
data = np.hstack((data, new_data))
if data is None:
raise PipeError("No data in pipe")
return data
def consume(self, num_rows):
"""
Flush data from the read buffer. The next call to :meth:`read` will
return any unflushed data followed by new incoming data.
Args:
num_rows: number of rows to flush from the read buffer
"""
if self.direction == Pipe.DIRECTION.OUTPUT:
raise PipeError("cannot consume from an output pipe")
raise PipeError("abstract method must be implemented by child")
def enable_cache(self, lines: int):
"""
Turn on caching for pipe writes. Data is only transmitted once the cache is full.
This improves system performance especially if :meth:`write` is called
rapidly with short arrays. Once enabled, caching cannot be disabled.
Args:
lines: cache size
"""
if self.direction == Pipe.DIRECTION.INPUT:
raise PipeError("cannot control cache on input pipes")
raise PipeError("abstract method must be implemented by child")
async def write(self, data):
"""
Write timestamped data to the pipe. Timestamps must be monotonically increasing
and should not overlap with existing stream data in the database. This method is a coroutine.
Args:
data (numpy.ndarray): May be a structured array with ``timestamp`` and ``data`` fields
or an unstructured array with timestamps in the first column.
>>> await pipe.write([[1000, 2, 3],[1001, 3, 4]])
"""
if self.direction == Pipe.DIRECTION.INPUT:
raise PipeError("cannot write to an input pipe")
raise PipeError("abstract method must be implemented by child")
async def read(self, flatten=False):
if flatten:
raise Exception("Not Implemented")
if self._reread:
self._reread = False
if self.last_block is None or len(self.last_block) == 0:
raise PipeError("No data left to reread")
return self.last_block
if len(self.data_blocks) == 0 and self.last_block is None:
raise EmptyPipeError()
if len(self.data_blocks) != 0:
block = self.data_blocks.popleft()
if len(self.data_blocks) == 0:
self.interval_break = True
self._last_read = True
elif self.data_blocks[0] is None:
self.data_blocks.popleft()
self.interval_break = True
else:
self.interval_break = False
if self.last_block is not None:
self.last_block = np.hstack((self.last_block, block))
else:
self.last_block = block
return self.last_block
async def flush_cache(self):
if self.closed:
raise PipeError("Cannot write to a closed pipe")
if self._cache_index > 0:
await self._write(self._cache[:self._cache_index])
self._cache_index = 0
self._cache = np.empty(len(self._cache), self.dtype)
async def close_interval(self):
if self.closed:
raise PipeError("Pipe is closed")
if self.writer is None:
return # nothing has been written yet so nothing to close
if self._caching:
await self.flush_cache()
self.writer.write(interval_token(self.layout).tobytes())
await self.writer.drain()
async def read(self, flatten=False) -> np.ndarray:
if self._failed:
await self.close()
raise PipeError('pipe failed')
# if reread is set just return the old data
if self._reread:
self._reread = False
if len(self.read_buffer) == 0:
raise PipeError("No data left to reread")
return self._format_data(self.read_buffer, flatten)
self._interval_break = False
# if the queue is empty and we have old data, just return the old data
# THIS IS REMOVED, OTHERWISE THE WRITER CAN BE STARVED AND NEVER CLOSE THE PIPE
# if self.queue.empty() and len(self.read_buffer) > 0:
# await asyncio.sleep(self.TIMEOUT_INTERVAL)
# return self._format_data(self.read_buffer, flatten)
# otherwise wait for at least one block
while self.queue.empty():
# if self._last_read:
# raise EmptyPipe() # trying to re-read old data
# if the buffer is empty and the queue is empty and the pipe is closed
if self.queue.empty() and self.closed:
self._last_read = True # from now on the is_empty flag will be set
# but an error will only be generated if all the remaining data is consumed
break # return unconsumed data
await asyncio.sleep(self.TIMEOUT_INTERVAL)
data_block = self._read(flatten)
# NOTE: There is a chance read will return an empty array-> if the producer simply closes the existing
# interval but all of the data is already consumed. This happens typically when a module fails and has to
# be restarted, then the inserter pipe will have no data (probably already has been read), but the terminating
# worker adds in an interval closing block [None] to the pipe. But if the producer also closes the pipe there
# is no reason to pass back empty data so raise an EmptyPipe exception instead
if len(data_block) == 0 and self.closed:
raise EmptyPipe()
return data_block
async def write(self, data: np.ndarray):
if self._failed:
await self.close()
raise PipeError('pipe failed')
if self.closed:
raise PipeError("Cannot write to a closed pipe")
if not self._validate_data(data):
return
# convert into a structured array
sarray = self._apply_dtype(data)
if self._caching:
for row in sarray:
self._cache[self._cache_index] = row
self._cache_index += 1
if self._cache_index >= len(self._cache):
await self.flush_cache()
else:
await self._write(sarray)
def close_interval_nowait(self):
if self.closed:
raise PipeError("Pipe is closed")
if self.writer is None:
return # nothing has been written yet so nothing to close
if self._cache_index > 0:
log.warning("dumping %d rows of cached data due on %s" %
(self._cache_index, self.name))
self._cache = np.empty(len(self._cache), self.dtype)
self._cache_index = 0
self.writer.write(interval_token(self.layout).tobytes())
def close_interval_nowait(self):
"""
Same as close_interval but this is not a coroutine. This should only be used for
unit testing
"""
if self._failed:
raise PipeError('pipe failed')
if self.debug:
print("[%s:write] closing interval" % self.name)
self.queue.put_nowait(None)
def subscribe(self, pipe):
if self.direction == Pipe.DIRECTION.INPUT:
raise PipeError("cannot subscribe to an input pipe")
self.subscribers.append(pipe)
def unsubscribe():
i = self.subscribers.index(pipe)
del self.subscribers[i]
return unsubscribe
def _apply_dtype(self, data: np.ndarray) -> np.ndarray:
"""convert [data] to the pipe's [dtype]"""
if data.ndim == 1:
# already a structured array just verify its data type
if data.dtype != self.dtype:
raise PipeError("wrong dtype for 1D (structured) array" +
"[%s] != req type [%s]" % (data.dtype,
self.dtype))
return data
elif data.ndim == 2:
# Convert to structured array
sarray = np.zeros(data.shape[0], dtype=self.dtype)
try:
sarray['timestamp'] = data[:, 0]
# Need the squeeze in case sarray['data'] is 1 dimensional
sarray['data'] = data[:, 1:]
return sarray
except (IndexError, ValueError):
raise PipeError("wrong number of fields for this data type")
else:
raise PipeError("wrong number of dimensions in array")
async def read(self, flatten=False) -> np.ndarray:
"""
Read stream data. By default this method returns a structured
array with ``timestamp`` and ``data`` fields. This method is a coroutine.
Args:
flatten: return an unstructured array (flat 2D matrix) with timestamps in the first column
Returns:
numpy.ndarray
>>> data = await pipe.read()
[1, 2, 3]
>>> data = await pipe.read(flatten=True)
# the same data is returned again
[1,2,3]
>>> pipe.consume(len(data))
# next call to read will return only new data
"""
if self.direction == Pipe.DIRECTION.OUTPUT:
raise PipeError("cannot read from an output pipe")
raise PipeError("abstract method must be implemented by child")
def write_nowait(self, data):
if self._failed:
raise PipeError('pipe failed')
if self.closed:
raise PipeError("Cannot write to a closed pipe")
if not self._validate_data(data):
return
# convert into a structured array
sarray = self._apply_dtype(data)
# send data to subscribers
for pipe in self.subscribers:
if type(pipe) is LocalPipe:
p: LocalPipe = pipe # to appease type checker
p.write_nowait(sarray)
else:
raise PipeError("cannot write_nowait to subscriber [%s]" %
pipe.name)
self.queue.put_nowait(sarray)
self.queued_rows += len(sarray)
if self.debug:
print("[%s:write] queueing block with [%d] rows" %
(self.name, len(sarray)))
async def write(self, data):
if self.closed:
raise PipeError("Cannot write to a closed pipe")
if not self._validate_data(data):
return
# make sure dtype is structured
sdata = self._apply_dtype(data)
if self._caching:
for row in sdata:
self._cache[self._cache_index] = row
self._cache_index += 1
if self._cache_index >= len(self._cache):
await self.flush_cache()
else:
await self._write(sdata)
def reread_last(self):
if len(self.read_buffer) == 0:
raise PipeError("No data left to reread")
self._reread = True
def write_nowait(self, data):
if self._closed:
raise PipeError("Cannot write to a closed pipe")
self.data_blocks.append(data)
def change_layout(self, layout: str):
raise PipeError("layout cannot be changed")
async def read(self, flatten=False) -> np.ndarray:
if self.reader is None:
self.reader, self._reader_close = await self.reader_factory()
if self.closed:
# this happens if close is called before the first read
if self._reader_close is not None:
self._reader_close()
raise PipeError("Cannot read from a closed pipe")
rowbytes = self.dtype.itemsize
max_rows = self.BUFFER_SIZE - (
self.last_index + len(self.unprocessed_np_buffer) % rowbytes)
if max_rows == 0:
# buffer is full, this must be consumed before a new read
return self._format_data(self.buffer[:self.last_index], flatten)
# if reread is set just return the old data
if self._reread:
self._reread = False
if self.last_index == 0:
raise PipeError("No data left to reread")
return self._format_data(self.buffer[:self.last_index], flatten)
# make sure we get at least one full row of data from read (depends on datatype)
raw = b''
while True:
new_data = b''
if self.reader.at_eof():
# do not raise an exception, but is_empty() will return True
#if self._last_read:
# raise EmptyPipe() # this data has already been read once
if (len(self.unprocessed_np_buffer) == 0
and self.last_index == 0):
raise EmptyPipe()
if len(self.unprocessed_np_buffer) == 0:
# no new data is coming in, read() will just return
# previously viewed data
self._last_read = True
break
try:
new_data = await asyncio.wait_for(
self.reader.read(max_rows * rowbytes),
self.TIMEOUT_INTERVAL)
except asyncio.TimeoutError:
pass
raw += new_data
if len(raw) < self.dtype.itemsize:
await asyncio.sleep(0.1)
else:
break
# extra_bytes: number of leftover bytes after % rowbytes
# byte_buffer: the extra_bytes from the last read
# unprocessed_np_buffer: data leftover from an interval break in the previous read
extra_bytes = (len(raw) + len(self.byte_buffer)) % rowbytes
if extra_bytes > 0:
np_buffer = self.byte_buffer + raw[:-extra_bytes]
self.byte_buffer = raw[-extra_bytes:]
elif len(self.byte_buffer) > 0:
np_buffer = self.byte_buffer + raw
self.byte_buffer = b''
else: # common case where byte_buffer is empty and no extra bytes
np_buffer = raw
self.byte_buffer = b''
# append unprocessed np_buffer from previous read
if len(self.unprocessed_np_buffer) > 0:
self.unprocessed_np_buffer = self.unprocessed_np_buffer + np_buffer
# check if we can process all the data, if not
# store the extra in unprocessed_np_buffer
max_bytes = max_rows * rowbytes
if len(self.unprocessed_np_buffer) <= max_bytes:
np_buffer = self.unprocessed_np_buffer
self.unprocessed_np_buffer = b''
else:
np_buffer = self.unprocessed_np_buffer[:max_bytes]
self.unprocessed_np_buffer = self.unprocessed_np_buffer[
max_bytes:]
# check for an interval
self.interval_break = False
loc = find_interval_token(np_buffer, self.layout)
if loc is not None:
self.unprocessed_np_buffer = np_buffer[
loc[1]:] + self.unprocessed_np_buffer
np_buffer = np_buffer[:loc[0]]
self.interval_break = True
data = np.frombuffer(np_buffer, dtype=self.dtype)
# append data onto buffer
self.buffer[self.last_index:self.last_index + len(data)] = data
self.last_index += len(data)
return self._format_data(self.buffer[:self.last_index], flatten)
def reread_last(self):
if self.last_index == 0:
raise PipeError("No data left to reread")
self._reread = True
