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# Passaggio 2: verifica la connettività al registro
**Importante**
Avviso di fine del supporto: i clienti esistenti potranno utilizzare Amazon QLDB fino alla fine del supporto, il 31/07/2025. Per ulteriori dettagli, consulta [Migrare un registro Amazon QLDB su Amazon Aurora PostgreSQL](https://aws.amazon.com/blogs/database/migrate-an-amazon-qldb-ledger-to-amazon-aurora-postgresql/).
In questo passaggio, verifichi di poterti connettere al `vehicle-registration` registro in Amazon QLDB utilizzando l'endpoint API dei dati transazionali.
**Per testare la connettività al registro**
1. Utilizzate il seguente programma (`connect_to_ledger.py`) per creare una connessione di sessione dati al `vehicle-registration` registro.
------
#### [ 3.x ]
```
# Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT-0
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of this
# software and associated documentation files (the "Software"), to deal in the Software
# without restriction, including without limitation the rights to use, copy, modify,
# merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
# This code expects that you have AWS credentials setup per:
# https://boto3.amazonaws.com/v1/documentation/api/latest/guide/quickstart.html
from logging import basicConfig, getLogger, INFO
from botocore.exceptions import ClientError
from pyqldb.driver.qldb_driver import QldbDriver
from pyqldbsamples.constants import Constants
logger = getLogger(__name__)
basicConfig(level=INFO)
def create_qldb_driver(ledger_name=Constants.LEDGER_NAME, region_name=None, endpoint_url=None, boto3_session=None):
"""
Create a QLDB driver for executing transactions.
:type ledger_name: str
:param ledger_name: The QLDB ledger name.
:type region_name: str
:param region_name: See [1].
:type endpoint_url: str
:param endpoint_url: See [1].
:type boto3_session: :py:class:`boto3.session.Session`
:param boto3_session: The boto3 session to create the client with (see [1]).
:rtype: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
:return: A QLDB driver object.
[1]: `Boto3 Session.client Reference `.
"""
qldb_driver = QldbDriver(ledger_name=ledger_name, region_name=region_name, endpoint_url=endpoint_url,
boto3_session=boto3_session)
return qldb_driver
def main(ledger_name=Constants.LEDGER_NAME):
"""
Connect to a given ledger using default settings.
"""
try:
with create_qldb_driver(ledger_name) as driver:
logger.info('Listing table names ')
for table in driver.list_tables():
logger.info(table)
except ClientError as ce:
logger.exception('Unable to list tables.')
raise ce
if __name__ == '__main__':
main()
```
**Nota**
Per eseguire transazioni di dati sul registro, è necessario creare un oggetto driver QLDB per connettersi a un registro specifico. Si tratta di un oggetto client diverso dall'`qldb_client`oggetto utilizzato nel passaggio precedente per creare il registro. Quel client precedente viene utilizzato solo per eseguire le operazioni dell'API di gestione elencate in. [Riferimento all'API Amazon QLDB](api-reference.md)
È necessario specificare un nome contabile quando si crea questo oggetto driver.
------
#### [ 2.x ]
```
# Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT-0
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of this
# software and associated documentation files (the "Software"), to deal in the Software
# without restriction, including without limitation the rights to use, copy, modify,
# merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
# This code expects that you have AWS credentials setup per:
# https://boto3.amazonaws.com/v1/documentation/api/latest/guide/quickstart.html
from logging import basicConfig, getLogger, INFO
from botocore.exceptions import ClientError
from pyqldb.driver.pooled_qldb_driver import PooledQldbDriver
from pyqldbsamples.constants import Constants
logger = getLogger(__name__)
basicConfig(level=INFO)
def create_qldb_driver(ledger_name=Constants.LEDGER_NAME, region_name=None, endpoint_url=None, boto3_session=None):
"""
Create a QLDB driver for creating sessions.
:type ledger_name: str
:param ledger_name: The QLDB ledger name.
:type region_name: str
:param region_name: See [1].
:type endpoint_url: str
:param endpoint_url: See [1].
:type boto3_session: :py:class:`boto3.session.Session`
:param boto3_session: The boto3 session to create the client with (see [1]).
:rtype: :py:class:`pyqldb.driver.pooled_qldb_driver.PooledQldbDriver`
:return: A pooled QLDB driver object.
[1]: `Boto3 Session.client Reference `.
"""
qldb_driver = PooledQldbDriver(ledger_name=ledger_name, region_name=region_name, endpoint_url=endpoint_url,
boto3_session=boto3_session)
return qldb_driver
def create_qldb_session():
"""
Retrieve a QLDB session object.
:rtype: :py:class:`pyqldb.session.pooled_qldb_session.PooledQldbSession`
:return: A pooled QLDB session object.
"""
qldb_session = pooled_qldb_driver.get_session()
return qldb_session
pooled_qldb_driver = create_qldb_driver()
if __name__ == '__main__':
"""
Connect to a session for a given ledger using default settings.
"""
try:
qldb_session = create_qldb_session()
logger.info('Listing table names ')
for table in qldb_session.list_tables():
logger.info(table)
except ClientError:
logger.exception('Unable to create session.')
```
**Nota**
Per eseguire transazioni di dati sul registro, è necessario creare un oggetto driver QLDB per connettersi a un registro specifico. Si tratta di un oggetto client diverso dall'`qldb_client`oggetto utilizzato nel passaggio precedente per creare il registro. Quel client precedente viene utilizzato solo per eseguire le operazioni dell'API di gestione elencate in. [Riferimento all'API Amazon QLDB](api-reference.md)
Innanzitutto, crea un oggetto driver QLDB in pool. È necessario specificare un nome contabile quando si crea questo driver.
Quindi, è possibile creare sessioni da questo oggetto driver condiviso.
------
1. Per eseguire il programma, immetti il comando seguente:
```
python connect_to_ledger.py
```
Per creare tabelle nel `vehicle-registration` registro, procedi a. [Passaggio 3: Creare tabelle, indici e dati di esempio](getting-started.python.step-3.md)