Connecting to a Managed Service for YDB database from a Python function in Yandex Cloud Functions

In the management console, select a folder where you want to create a service account.

At the top of the screen, go to the Service accounts tab.

Click Create service account.

Enter a name for the service account, e.g., sa-function. The naming requirements are as follows:

• The name must be from 3 to 63 characters long.
• It may contain lowercase Latin letters, numbers, and hyphens.
• The first character must be a letter and the last character cannot be a hyphen.

Click Add role and select editor.

Click Create.

In the management console, select the folder where you want to create a database.

In the list of services, select Managed Service for YDB.

Click Create a database.

Name the database. The naming requirements are as follows:

• The name must be from 3 to 63 characters long.
• It may contain lowercase Latin letters, numbers, and hyphens.
• The first character must be a letter and the last character cannot be a hyphen.

Under Database type, select Serverless.

Click Create a database.

Wait for the DB to start. When a database is being created, it has the Provisioning status. Once it is ready for use, its status will change to Running.

Click the name of the created database.

Under Connection, find the Endpoint field and save its value. You will need it at the next step.

In the management console, select the folder to create the function in.

In the list of services, select Cloud Functions.

Click Create function.

Enter a name and description for the function. The naming requirements are as follows:

• The name must be from 3 to 63 characters long.
• It may contain lowercase Latin letters, numbers, and hyphens.
• The first character must be a letter and the last character cannot be a hyphen.

Click Create.

Under Editor, select Python as the runtime environment, disable the Add files with code examples option, and click Continue.

Under Function code, create a file named index.py and paste the following code to it:

import os
import ydb
import ydb.iam

# Create driver in global space.
driver = ydb.Driver(
  endpoint=os.getenv('YDB_ENDPOINT'),
  database=os.getenv('YDB_DATABASE'),
  credentials=ydb.iam.MetadataUrlCredentials(),
)

# Wait for the driver to become active for requests.

driver.wait(fail_fast=True, timeout=5)

# Create the session pool instance to manage YDB sessions.
pool = ydb.SessionPool(driver)

def execute_query(session):
  # Create the transaction and execute query.
  return session.transaction().execute(
    'select 1 as cnt;',
    commit_tx=True,
    settings=ydb.BaseRequestSettings().with_timeout(3).with_operation_timeout(2)
  )

def handler(event, context):
  # Execute query with the retry_operation helper.
  result = pool.retry_operation_sync(execute_query)
  return {
    'statusCode': 200,
    'body': str(result[0].rows[0].cnt == 1),
  }

Under Function code, create a file named requirements.txt and paste the following text into it:

ydb

Specify the entry point: index.handler.

Select a service account, e.g., sa-function.

Configure the environment variables:

• YDB_ENDPOINT: Enter the first part of the previously saved Endpoint field value (preceding /?database=), e.g., grpcs://ydb.serverless.yandexcloud.net:2135.
• YDB_DATABASE: Enter the second part of the previously saved Endpoint field value (following /?database=), e.g., /ru-central1/r1gra875baom********/g5n22e7ejfr1********.

Click Save changes.

Go to the Testing tab.

Click Run test and check out the testing results.

If a DB connection is established and a query is executed, the function status will change to Done and its output will contain the following text:

{
  "statusCode": 200,
  "body": "True"
}