def get_segments(flags,
segments,
cache=None,
url='https://segdb-er.ligo.caltech.edu',
**kwargs):
"""Fetch some segments from the segment database
Parameters
----------
flags : `str`, `list`
one of more flags for which to query
segments : `~gwpy.segments.DataQualityFlag`, `~gwpy.segments.SegmentList`
span over which to query for flag segments
cache : `~glue.lal.Cache`, optional
cache of files to use as data source
url : `str`
URL of segment database, if ``cache`` is not given
**kwargs
other keyword arguments to pass to either
`~gwpy.segments.DataQualityFlag.read` (if ``cache`` is given) or
`~gwpy.segments.DataQualityFlag.query` (otherwise)
Returns
-------
segments : `~gwpy.segments.DataQualityFlag`,
`~gwpy.segments.DataQualityDict`
a single `~gwpy.segments.DataQualityFlag` (if ``flags`` is given
as a `str`), or a `~gwpy.segments.DataQualityDict` (if ``flags``
is given as a `list`)
"""
# format segments
if isinstance(segments, DataQualityFlag):
segments = segments.active
elif isinstance(segments, tuple):
segments = [Segment(to_gps(segments[0]), to_gps(segments[1]))]
segments = SegmentList(segments)
# get format for files
if cache is not None and not isinstance(cache, Cache):
kwargs.setdefault(
'format',
_get_valid_format('read', DataQualityFlag, None, None,
(cache[0], ), {}))
# populate an existing set of flags
if isinstance(flags, (DataQualityFlag, DataQualityDict)):
return flags.populate(source=cache or url, segments=segments, **kwargs)
# query one flag
elif cache is None and isinstance(flags, str):
return DataQualityFlag.query(flags, segments, url=url, **kwargs)
# query lots of flags
elif cache is None:
return DataQualityDict.query(flags, segments, url=url, **kwargs)
# read one flag
elif flags is None or isinstance(flags, str):
segs = DataQualityFlag.read(cache, flags, coalesce=False, **kwargs)
if segs.known:
segs.known &= segments
else:
segs.known = segments
segs.active &= segments
return segs
# read lots of flags
else:
segs = DataQualityDict.read(cache, flags, coalesce=True, **kwargs)
for name, flag in segs.items():
flag.known &= segments
flag.active &= segments
return segs
