impl

PynamoDB Context Manager for Using Specific Boto3 Sessions

This module provides a context manager that allows PynamoDB models to temporarily use different AWS credentials/sessions without modifying the model definition. This is particularly useful for:

  • Multi-account operations

  • Different AWS profiles for different environments

  • Temporary credential switching

  • Cross-account DynamoDB operations

pynamodb_session_manager.impl.use_boto_session(table: Type[Model], bsm: BotoSesManager | None = None, restore_on_exit: bool = True)[source]

Context manager to temporarily switch PynamoDB model to use different AWS credentials.

This context manager allows a PynamoDB model to temporarily use different AWS credentials by leveraging the boto-session-manager’s awscli() context manager and manipulating the model’s connection and region settings.

Parameters:

  • table – The PynamoDB model class that will use the new credentials.

  • bsm – The boto session manager instance containing the target AWS credentials/profile to use. If None, the context manager has no effect, providing a clean API where users can conditionally switch credentials without separate if/else logic. See https://pypi.org/project/boto-session-manager/

  • restore_on_exit – If True, restore original connection on exit if False, keep current connection for subsequent operations. See also reset_connection().

Yields:

None, This is a context manager that doesn’t return a value

Usage:

# Define your model
class MyModel(Model):
    class Meta:
        table_name = "my_table"
        region = "us-east-1"

    id = NumberAttribute(hash_key=True)

# Use different credentials temporarily
target_bsm = BotoSesManager(profile_name="target_profile")

with target_aws_cred(target_bsm, MyModel):
    # All operations here use the target_profile credentials
    MyModel.create_table()
    item = MyModel(id=1)
    item.save()

# Back to original credentials
items = MyModel.scan()  # This uses default credentials

How it works:

  1. Saves the current region setting from the model’s Meta class

  2. Enters the boto session manager’s awscli() context (sets env vars)

  3. Clears the model’s cached connection to force recreation

  4. Updates the model’s region to match the session manager’s region

  5. Creates a new Connection object with the new region

  6. On exit, restores the original region and clears connection again

Note

  • The model’s _connection attribute is set to None to force PynamoDB

    to create a new connection with the current environment variables

  • The region is temporarily changed to ensure consistency with the session

  • All changes are reverted when exiting the context manager when restore_on_exit is True

pynamodb_session_manager.impl.reset_connection(table: Type[Model])[source]

Reset the PynamoDB model’s connection to use the default AWS connection.

This is useful when you have changed AWS credentials using use_boto_session() context manager, and then want to revert back to the default PynamoDB behavior.

Parameters:

table – The PynamoDB model class whose connection should be reset.

Usage:

# Define your model
class MyModel(Model):
    ...

# Use different credentials and keep the connection
with use_boto_session(target_bsm, MyModel, restore_on_exit=False):
    ...

# Reset the connection to use the default AWS credentials
reset_connection(MyModel)