def read_samples(self, samples_path=None):
"""Read and unpack all the samples in to a list of tuples (timestamp, value)"""
# N.B. Doesn't lock
if samples_path is None:
samples_path = self.samples_path
with open(samples_path, 'rb') as f:
sample_format = self._read_header(f).decode('utf-8')
sample_struct = struct.Struct(py2bytes(sample_format))
sample_size = sample_struct.size
read_sample = partial(f.read, sample_size)
unpack = sample_struct.unpack
samples = [unpack(sample) for sample in iter(read_sample, b'')]
return samples
def __init__(self, path, name, time_format='d', value_format='d', max_samples=1000):
self.path = abspath(path)
self.name = name
self.time_format = time_format
self.value_format = value_format
self.max_samples = max_samples
self.samples_path = join(path, 'samples.smp')
self.samples_snapshot_path = join(path, 'samples.smp.snapshot')
sample_format = self.sample_format = '<' + time_format + value_format
sample_struct = self.sample_struct = struct.Struct(py2bytes(sample_format))
self.sample_pack = sample_struct.pack
self.sample_unpack = sample_struct.unpack
self.sample_size = sample_struct.size
self.max_file_size = len(self.header) + self.sample_size * self.max_samples
self.lock = RLock()
self.check_create()
super(Sampler, self).__init__()