sqlaudit 0.2.0

SQLAlchemy extension that provides an easy way to track changes to your database models.

SQLAudit

SQLAudit is a SQLAlchemy extension that provides an easy way to track changes to your database models. It automatically creates an audit trail of changes made to your models, including the user who made the change, the timestamp of the change.

It is designed to work with SQLAlchemy's ORM and provides a simple way to track changes to your models without having to write custom code for each model. SQLAudit only requires you to decorate your models with the @track_table decorator, and it will automatically track changes to the specified fields.

@track_table(tracked_fields=["name", "email", "user_id"])
class Customer(Base):
    __tablename__ = "customers"

    customer_id: Mapped[int] = mapped_column(
        Integer, primary_key=True, autoincrement=True
    )
    name: Mapped[str] = mapped_column(String)
    email: Mapped[str] = mapped_column(String)
    created_by: Mapped[str] = mapped_column(ForeignKey("users.user_id"))

Notice

This project is in its early stages and is not yet ready for production use. Note that new updates will probably break the API, so please use it with caution.

Quick start

To get started with SQLAudit, you need to install it using pip:

pip install sqlaudit

Follow the steps below to set up and use SQLAudit in your SQLAlchemy application.

This short guide demonstrates how to setup and use SQLAudit and allow the tracking of changes to your SQLAlchemy models, which will also include the user who made the change.

Step 1: Define your Base and User model

We will first create a very simple in-memory SQLite database to demonstrate how to use SQLAudit. You can use any database supported by SQLAlchemy, but for simplicity, we will use an in-memory SQLite database. As previously mentioned, we will also want to track which user made the changes to the models. Thus we also define a User model.

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, DeclarativeBase

# Create an in-memory SQLite database
DATABASE_URL = "sqlite:///:memory:"
engine = create_engine(DATABASE_URL, connect_args={"check_same_thread": False})

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

class Base(DeclarativeBase):
    pass


class User(Base):
    __tablename__ = "users"
    user_id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
    name: Mapped[string] = mapped_column()

Step 2: Configure SQLAudit

The configuration for SQLAudit is done using the SQLAuditConfig class. We create a configuration object that specifies the session factory, user model, and a callback to get the user ID from the instance.

We need four things to configure SQLAudit:

1. session_factory: A session factory that returns a SQLAlchemy session.
2. user_model: A user model that represents the user who made the changes.
3. user_model_user_id_field: A field in the user model that represents the user ID.
4. get_user_id_callback: A callback function that retrieves the user ID from the instance. In this example, we will use a mock function to get the user ID, however in a real application, you could for example use contextvars.

from sqlaudit.config import SQLAuditConfig, set_config

def get_db():
    """Yield a database session for an in-memory SQLite DB."""
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

def get_user_id_mock()
    """Mock function to get user ID from an instance."""
    return 1


config = SQLAuditConfig(
    session_factory=get_db,
    user_model=User,
    user_model_user_id_field="user_id",
    get_user_id_callback=get_user_id_from_instance,
)

set_config(config) # We set the global configuration for SQLAudit

Step 3: Add SQLAudit to your models

To enable auditing for your models use the @track_table decorator. This decorator will automatically track changes to the model and store them in the audit table. There are various options you can pass to the decorator to customize the behavior. The most basic usage only requires a list of strings representing the columns you want to track.

from sqlaudit.decorators import track_table
from sqlalchemy import Integer, String, ForeignKey

@track_table(tracked_fields=["name", "email", "user_id"])
class Customer(Base):
    __tablename__ = "customers"

    customer_id: Mapped[int] = mapped_column(
        Integer, primary_key=True, autoincrement=True
    )
    name: Mapped[str] = mapped_column(String)
    email: Mapped[str] = mapped_column(String)
    user_id: Mapped[str] = mapped_column(ForeignKey("users.user_id"))

Step 4: Register the SQLAudit hooks

SQLAudit uses two SQLAlchemy events to track changes: before_flush and after_flush. You need to register these hooks to enable auditing.

We will be doing this in a startup function that will be called when the application starts.

from sqlaudit.hooks import register_hooks

if __name__ == "__main__":
    Base.metadata.create_all(engine)

    register_hooks()

Step 5: Use the session to make changes

Now you can use the session to make changes to your models. SQLAudit will automatically track these changes and store them in the audit table.

from sqlaudit.retrieval import get_resource_changes

with next(get_db()) as session:
    user = User()
    session.add(user)
    session.commit()

    new_customer = Customer(
        name="John Doe", email="[e-mail]", user_id=user.user_id
    )

    session.add(new_customer)

    session.commit()
    print(
        f"Customer {new_customer.customer_id} added with name {new_customer.name} and email {new_customer.email}."
    )

    new_customer2 = Customer(
        name="Jane Doe", email="[e-mail]", user_id=user.user_id
    )

    session.add(new_customer2)

    session.commit()
    print(
        f"Customer {new_customer2.customer_id} added with name {new_customer2.name} and email {new_customer2.email}."
    )

    session.refresh(new_customer2)

    new_customer2.name = "Jane Smith"

    session.commit()

    changes = get_resource_changes(
        model_class=Customer,
        session=session,
        filter_resource_ids=["1,", "2"],
        filter_user_ids=str(user.user_id), # Our mock user ID will return a 1 
    )

    for change in changes:
        print(
            f"FIELD: '{change.field_name}' CHANGED AT {str(change.timestamp)} TO {change.new_value} (OLD: {change.old_value}) BY USER ID {change.changed_by}"
        )

Full Example Script

Click to expand the full example script

from sqlalchemy import ForeignKey, Integer, String, create_engine
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, sessionmaker

from sqlaudit.config import SQLAuditConfig, set_config
from sqlaudit.decorators import track_table
from sqlaudit.hooks import register_hooks
from sqlaudit.retrieval import get_resource_changes


# Create an in-memory SQLite database
DATABASE_URL = "sqlite:///:memory:"
engine = create_engine(DATABASE_URL, connect_args={"check_same_thread": False})

# Create a session factory
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)


def get_db():
    """
    Helper function to get a database session.
    This function is used to provide a database session to the application.
    """
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()


class Base(DeclarativeBase):
    """
    Base class for declarative class definitions.
    """

    pass


# Define the User model
class User(Base):
    """
    User model representing users in the system.
    """

    __tablename__ = "users"
    user_id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
    # Add more columns as needed


# Create a user instance
user = User()


def get_user_id_from_instance() -> int:
    """
    Returns the user_id from the instance.
    This function is used to retrieve the user ID for auditing purposes.
    """
    return user.user_id


# Set the global audit configuration
config = SQLAuditConfig(
    session_factory=get_db,
    user_model=User,
    user_model_user_id_field="user_id",
    get_user_id_callback=get_user_id_from_instance,
)
set_config(config)


# Define the Customer model with tracked fields for auditing
@track_table(tracked_fields=["name", "email", "user_id"], table_label="Customer")
class Customer(Base):
    """
    Customer model representing customers in the system.
    This model is tracked for changes in the specified fields.
    """

    __tablename__ = "customers"

    customer_id: Mapped[int] = mapped_column(
        Integer, primary_key=True, autoincrement=True
    )
    name: Mapped[str] = mapped_column(String)
    email: Mapped[str] = mapped_column(String)
    user_id: Mapped[str] = mapped_column(ForeignKey("users.user_id"), nullable=False)


if __name__ == "__main__":
    # Create all tables in the database
    Base.metadata.create_all(engine)

    # Get a database session
    with next(get_db()) as session:
        # Register hooks for auditing
        register_hooks()

        # Add the user to the session and commit
        session.add(user)
        session.commit()

        # Create and add a new customer
        new_customer = Customer(
            name="John Doe", email="[e-mail]", user_id=user.user_id
        )

        session.add(new_customer)
        session.commit()

        print(
            f"Customer {new_customer.customer_id} added with name {new_customer.name} and email {new_customer.email}."
        )

        # Check if the customer is in the database
        customer = (
            session.query(Customer)
            .filter_by(customer_id=new_customer.customer_id)
            .first()
        )

        # Create and add another customer
        new_customer2 = Customer(
            name="Jane Doe", email="[e-mail]", user_id=user.user_id
        )

        session.add(new_customer2)
        session.commit()

        print(
            f"Customer {new_customer2.customer_id} added with name {new_customer2.name} and email {new_customer2.email}."
        )

        # Refresh the session and update the customer's name so we have some more data to track
        session.refresh(new_customer2)
        new_customer2.name = "Jane Smith"
        session.commit()

        # Retrieve and print changes for the customers
        changes = get_resource_changes(
            model_class=Customer,
            session=session,
            filter_resource_ids=new_customer2.customer_id,
        )

        for change in changes:
            print(
                f"FIELD: '{change.field_name}' CHANGED AT {str(change.timestamp)} TO {change.new_value} (OLD: {change.old_value}) BY USER ID {change.changed_by}"
            )

Documentation

sqlaudit.retrieval.get_resource_changes()

The get_resource_changes function in the sqlaudit.retrieval module is used to retrieve changes made to a specific resource in the database. It allows you to filter changes by resource IDs, user IDs, and other criteria. This function is particularly useful for auditing purposes, as it enables you to track modifications made to your models over time.

Parameters

• model_class: required (e.g. User) The SQLAlchemy model class for which you want to retrieve changes.
• session: required The SQLAlchemy session to use for querying the database.
• filter_resource_ids: required A ResourceIdType or a list of ResourceIdType to filter the changes by resource IDs. This can be a single ID or a list of IDs. ResourceIdType can be a str, int, or uuid.UUID.
• filter_fields: optional A str or a list of str to filter the changes by specific fields. If not provided, all fields will be included.
• filter_user_ids: optional A ResourceIdType or a list of ResourceIdType to filter the changes by user IDs. If not provided, all user IDs will be included. ResourceIdType can be a str, int, or uuid.UUID.
• filter_date_range: optional tuple[datetime | None, datetime | None] to filter the changes by a date range. If not provided, all dates will be included.