Export Interface/Driver walkthrough

This guide provides an overview of the driver interface, including details of its structure and functionality. Additionally, it offers instructions on adding a new driver and utilizing different backends to export audit violations.

Driver interface

type Driver interface {
    // Publish publishes single message with specific subject using a connection
    Publish(ctx context.Context, connectionName string, data interface{}, subject string) error

    // CloseConnection closes a connection
    CloseConnection(connectionName string) error

    // UpdateConnection updates an existing connection
    UpdateConnection(ctx context.Context, connectionName string, config interface{}) error

    // CreateConnection creates new connection
    CreateConnection(ctx context.Context, connectionName string, config interface{}) error
}

As an example, the Dapr driver implements these methods to publish message and manage connection to do so. Please refer to dapr.go to understand the logic that goes in each of these methods.

How to add new driver to export audit violations to foo backend

A driver must maintain a map of open connections associated with backend foo.

type Connection struct {
    // properties needed for individual connection
}

type Foo struct {
    openConnections map[string]Connection
}

const (
    Name = "foo"
)

var Connections = &Foo{
    openConnections: make(map[string]Connection),
}

A driver must implement the Driver interface.

func (r *Foo) Publish(ctx context.Context, connectionName string, data interface{}, subject string) error {
  ...
}

func (r *Foo) loseConnection(connectionName string) error {
  ...
}

func (r *Foo) UpdateConnection(ctx context.Context, connectionName string, config interface{}) error {
  ...
}

func (r *Foo) CreateConnection(ctx context.Context, connectionName string, config interface{}) error {
  ...
}

This newly added driver's Connections exported variable must be added to the map of SupportedDrivers in system.go. For example,

var SupportedDrivers = map[string]driver.Driver{
    dapr.Name: dapr.Connections,
  foo.Name: foo.Connections,
}

And thats it! Exporter system will take the newly added driver into account and whenever a configMap to establish connection to export message is created.

How to establish connections to different backend

To enable audit to use this driver to publish messages, a connection configMap with appropriate config and driver is needed. For example,

apiVersion: v1
kind: ConfigMap
metadata:
  name: audit
  namespace: gatekeeper-system
data:
  driver: "foo"
  config: |
    {
      <config needed for foo connection>
    }

The data.driver field must exist and must match one of the keys of the SupportedDrivers map that was defined earlier to use the corresponding driver. The data.config field in the configuration can vary depending on the driver being used. For dapr driver, data.config must be {"component": "pubsub"}.