def check_and_put(self, table, row, check_column, check_value=None):
"""Put(insert) one row to the table when the given condition is satisfied.
Atomically checks if a row/family/qualifier value matches the expected value.
If it does, it adds the put.
If the passed value is None(or b''), the check is for the lack of column (ie: non-existance)
Args:
table (str): Table name.
row (Row): Row to insert.
check_column (str): Column to check.
check_value (bytes): Value to check.
Returns:
True: Success.
False: Not modified. (The given condition is not satisfied.)
Raises:
RESTError: REST server returns other errors.
"""
cell_set = protobuf_schema.CellSet()
row_ = cell_set.rows.add()
row_.key = row.key.encode()
for column, data in row.items():
value = row_.values.add()
value.column = column.encode()
value.data = data
if check_column is not None:
value = row_.values.add()
value.column = check_column.encode()
value.data = check_value if check_value is not None else b''
url = '/'.join((self._base_url, table, 'fakerow?check=put'))
else:
url = '/'.join((self._base_url, table, 'fakerow'))
response = self._session.post(url=url,
headers={
'Content-Type':
'application/x-protobuf',
'Accept': 'application/x-protobuf'
},
data=cell_set.SerializeToString())
code = response.status_code
if code == CODE_OK:
return True # put success
elif code == CODE_NOT_MODIFIED:
return False # not modified
else:
raise RESTError(code, response.text)
def get(self, table, key, columns=None):
"""Query to get a row object with a row key.
Args:
table (str): Table name.
key (str): Row key.
columns (tuple[str]|list[str]): Columns to fetch.
Returns:
Row: The row object.
None: The row does not exist.
Raises:
RESTError: REST server returns other errors.
"""
url = '/'.join((self._base_url, table, key))
if columns is not None:
url += '/' + ','.join(columns)
response = self._session.get(
url=url, headers={'Accept': 'application/x-protobuf'})
code = response.status_code
if code == CODE_OK:
cell_set = protobuf_schema.CellSet()
cell_set.ParseFromString(response.content)
count = len(cell_set.rows)
if count == 1:
row = cell_set.rows[0]
return Row(key=row.key.decode(),
cells={
value.column.decode(): value.data
for value in row.values
})
elif count == 0:
return None
else:
return [
Row(key=row.key.decode(),
cells={
value.column.decode(): value.data
for value in row.values
}) for row in cell_set.rows
]
elif code == CODE_NOT_FOUND:
return None
else:
raise RESTError(code, response.text)
def iter_scanner(self, scanner_url, num_rows=None):
"""Iterate a scanner.
Args:
scanner_url (str): The scanner URL which returned from "create_scanner".
If the url is None, the method will return None.
num_rows (int): Max number of rows will be returned.
Returns:
list[Row]: List of row.
None: There is not more content to be iterated.
Raises:
RESTError: REST server returns other errors.
Note that the scanner will not be closed(deleted) when the rows exhausted.
You should close it manually.
"""
if scanner_url is None:
return None
if num_rows is not None:
scanner_url = scanner_url + '?n=' + str(num_rows)
response = self._session.get(
url=scanner_url, headers={'Accept': 'application/x-protobuf'})
code = response.status_code
if code == CODE_OK:
cell_set = protobuf_schema.CellSet()
cell_set.ParseFromString(response.content)
return [
Row(key=row.key.decode(),
cells={
value.column.decode(): value.data
for value in row.values
}) for row in cell_set.rows
]
elif code == CODE_NO_CONTENT:
return None
else:
raise RESTError(code, response.text)
def put_many(self, table, rows):
"""Put(insert) multiple rows to the table.
Args:
table (str): Table name.
rows (list[Row] | collections.deque): Row to insert.
Returns:
True: Success.
Raises:
RESTError: REST server returns other errors.
"""
cell_set = protobuf_schema.CellSet()
for row in rows:
row_ = cell_set.rows.add()
row_.key = row.key.encode()
for column, data in row.items():
value = row_.values.add()
value.column = column.encode()
value.data = data
response = self._session.post(url='/'.join(
(self._base_url, table, 'fakerow')),
headers={
'Content-Type':
'application/x-protobuf',
'Accept': 'application/x-protobuf'
},
data=cell_set.SerializeToString())
code = response.status_code
if code == CODE_OK:
return True
else:
raise RESTError(code, response.text)