class CacheFilter:
"""
A class which takes an exporter and returns records which have
changed by comparing them against cached data
"""
def __init__(self, export_scheme, options):
self.export_scheme = export_scheme
self.options = options
# Load our cached state if given
if not options.state_file:
# fake being a shelf
self.cached_state = UserDict()
self.cached_state.close = lambda: None
else:
self.cached_state = shelve.open(options.state_file)
def extract_row_key(self, row):
"""
Extract a tuple from a row to uniquely identify it
"""
key = [row['case_id'], row['syndrome_id']]
for form in self.export_scheme.include_forms:
base = '%s.form_id' % form
if base in row:
key.append(row[base])
else:
n = 0
while '%s.%d' % (base, n) in row:
key.append(row['%s.%d' % (base, n)])
n += 1
return tuple(key)
def __iter__(self):
# Run over value tuples checking against cached state
for row in dictifying_filter_gen(self.export_scheme.row_gen()):
row_key = self.extract_row_key(row)
row_key_repr = repr(row_key)
current_values = [row[f] for f in self.options.monitored_fields]
cached_values = self.cached_state.get(
row_key_repr, [None] * len(self.options.monitored_fields))
changed_values = [
(f, cached_values[n], row[f])
for n, f in enumerate(self.options.monitored_fields)
if row[f] != cached_values[n]
]
if changed_values:
#print row_key, '->', changed_values
yield (row, changed_values)
def update_cache(self, row):
row_key = self.extract_row_key(row)
row_key_repr = repr(row_key)
current_values = [row[f] for f in self.options.monitored_fields]
if not self.options.dry_run:
self.cached_state[row_key_repr] = current_values
def commit(self):
# Clean up
self.cached_state.close()
class CacheFilter:
"""
A class which takes an exporter and returns records which have
changed by comparing them against cached data
"""
def __init__(self, export_scheme, options):
self.export_scheme = export_scheme
self.options = options
# Load our cached state if given
if not options.state_file:
# fake being a shelf
self.cached_state = UserDict()
self.cached_state.close = lambda: None
else:
self.cached_state = shelve.open(options.state_file)
def extract_row_key(self, row):
"""
Extract a tuple from a row to uniquely identify it
"""
key = [row['case_id'], row['syndrome_id']]
for form in self.export_scheme.include_forms:
base = '%s.form_id' % form
if base in row:
key.append(row[base])
else:
n = 0
while '%s.%d' % (base, n) in row:
key.append(row['%s.%d' % (base, n)])
n += 1
return tuple(key)
def __iter__(self):
# Run over value tuples checking against cached state
for row in dictifying_filter_gen(self.export_scheme.row_gen()):
row_key = self.extract_row_key(row)
row_key_repr = repr(row_key)
current_values = [ row[f] for f in self.options.monitored_fields ]
cached_values = self.cached_state.get(row_key_repr, [None] * len(self.options.monitored_fields))
changed_values = [ (f, cached_values[n], row[f]) for n, f in enumerate(self.options.monitored_fields) if row[f] != cached_values[n] ]
if changed_values:
#print row_key, '->', changed_values
yield (row, changed_values)
def update_cache(self, row):
row_key = self.extract_row_key(row)
row_key_repr = repr(row_key)
current_values = [ row[f] for f in self.options.monitored_fields ]
if not self.options.dry_run:
self.cached_state[row_key_repr] = current_values
def commit(self):
# Clean up
self.cached_state.close()
