def create_table_indexes(self, index_attributes=[]):
"""Create index on tables in a particular ledger."""
logger.info('Creating index on all tables in a single transaction...')
with qldb.session(self.ledger_name) as session:
for index_attribute in index_attributes:
session.execute_lambda(
lambda x: DdlServices.do_create_table_index(x, self.hash_table_name, index_attribute),
lambda retry_attempt: logger.info('Retrying due to OCC conflict...'))
logger.info('Index created successfully.')
def get_table_data(ledger_name, table_name, where='1=1', limit=10, offset=0):
""" Scan for all the documents in a table."""
try:
with qldb.session(ledger_name) as session:
# Scan all the tables and print their documents.
tables = session.list_tables()
for table in tables:
cursor = session.execute_lambda(
lambda executor: DmlServices.scan_table(executor, table_name, where, limit, offset),
retry_indicator=lambda retry_attempt: logger.info('Retrying due to OCC conflict...'))
logger.info('Scan successful!')
return parse_result(cursor)
except Exception as e:
logger.exception('Unable to scan tables. {}'.format(e))
def table_exist(self):
"""
Connect to a session for a given ledger using default settings.
"""
try:
qldb_session = qldb.session(self.ledger_name)
logger.info('Listing table names ')
tables = qldb_session.list_tables()
_tables = []
for table in tables:
_tables.append(table)
return self.hash_table_name in _tables
except Exception as e:
logger.exception('Unable to create session.')
return False
def drop_table(ledger_name=None, table_name=None):
"""Create a Table"""
try:
with qldb.session(ledger_name) as session:
session.execute_lambda(
lambda x: DdlServices.do_drop_table(x, table_name),
lambda retry_attempt: logger.info(
'Retrying due to OCC conflict...'))
logger.info('Table dropped successfully.')
return success_response('Table dropped successfully.',
HTTPStatus.CREATED)
except Exception:
logger.exception('Error creating table.')
return fail_response(
'Unable to create the table. Please try again.',
HTTPStatus.UNPROCESSABLE_ENTITY)
def insert_documents(ledger_name, table_name, documents):
"""
Insert documents into a table in a QLDB ledger.
"""
try:
with qldb.session(ledger_name) as session:
# An INSERT statement creates the initial revision of a document with a version number of zero.
# QLDB also assigns a unique document identifier in GUID format as part of the metadata.
session.execute_lambda(
lambda executor: DmlServices.do_insert_documents(executor, table_name, documents),
lambda retry_attempt: logger.info('Retrying due to OCC conflict...'))
logger.info('Documents inserted successfully!')
return success_response('Ledger is active and ready to use.', HTTPStatus.CREATED)
except Exception as e:
logger.exception('Error inserting or updating documents.')
return fail_response('Error inserting or updating documents. error: {}. Please try again.'.format(e),
HTTPStatus.UNPROCESSABLE_ENTITY)
def list_tables(ledger_name):
"""
Connect to a session for a given ledger using default settings.
"""
try:
qldb_session = qldb.session(ledger_name)
logger.info('Listing table names ')
tables = qldb_session.list_tables()
_tables = []
for table in tables:
_tables.append(table)
return _tables
except Exception as e:
logger.exception('Unable to create session.')
return fail_response(
'Unable to connect ledgers!. Please try again.',
HTTPStatus.UNPROCESSABLE_ENTITY)
def create_table_index(ledger_name=None,
table_name=None,
index_attribute=None):
"""Create index on tables in a particular ledger."""
logger.info('Creating index on all tables in a single transaction...')
try:
with qldb.session(ledger_name) as session:
session.execute_lambda(
lambda x: DdlServices.do_create_table_index(
x, table_name, index_attribute), lambda retry_attempt:
logger.info('Retrying due to OCC conflict...'))
logger.info('Index created successfully.')
return success_response('Index created successfully.',
HTTPStatus.CREATED)
except Exception:
logger.exception('Unable to create index.')
return fail_response(
'Unable to create the index. Please try again.',
HTTPStatus.UNPROCESSABLE_ENTITY)
def verify_block(self):
"""
Get a journal block from a QLDB ledger.
After getting the block, we get the digest of the ledger and validate the
proof returned in the getBlock response.
"""
try:
data = get_requested_data()
with qldb.session(data["ledger_name"]) as session:
cursor = session.execute_lambda(lambda executor: query_revision_history(executor,
data["table_name"],
data["condition_str"],
data["condition_value"]),
lambda retry_indicator: logger.info('Retrying due to OCC conflict...'))
row = next(cursor)
block_address = row.get('blockAddress')
verify_block(data["ledger_name"], block_address)
except Exception:
logger.exception('Unable to query vehicle registration by Vin.')
def drop_table(self):
"""Create a Table"""
with qldb.session(self.ledger_name) as session:
session.execute_lambda(lambda x: DdlServices.do_drop_table(x, self.hash_table_name),
lambda retry_attempt: logger.info('Retrying due to OCC conflict...'))
logger.info('Table dropped successfully.')