CommandStore

The CommandStore interface in comby defines the contract for managing commands within a Command Query Responsibility Segregation (CQRS) architecture. It enables the storage, retrieval, modification, and deletion of commands in a scalable and efficient manner. Developers can implement this interface to integrate with various storage backends, ensuring flexibility and adaptability across different environments.

Interface

The CommandStore interface provides methods for initialization, command management (creation, retrieval, modification, and deletion), metadata utilities (e.g., totals, store info), and maintenance (e.g., resetting and closing connections). This ensures flexible configuration, efficient command handling, and adaptability for various use cases.

type CommandStore interface {
	// Init initializes the command store with the provided options.
	Init(ctx context.Context, opts ...CommandStoreOption) error

	// Create adds a new command to the store.
	Create(ctx context.Context, opts ...CommandStoreCreateOption) error

	// Get retrieves a command by its unique identifier.
	Get(ctx context.Context, opts ...CommandStoreGetOption) (Command, error)

	// List retrieves a list of commands based on the provided options.
	List(ctx context.Context, opts ...CommandStoreListOption) ([]Command, int64, error)

	// Update modifies an existing command in the store.
	Update(ctx context.Context, opts ...CommandStoreUpdateOption) error

	// Delete removes a command by its unique identifier.
	Delete(ctx context.Context, opts ...CommandStoreDeleteOption) error

	// Total returns the total number of commands in the store.
	Total(ctx context.Context) int64

	// Close closes the command store connection.
	Close(ctx context.Context) error

	// Options returns the configuration options of the command store.
	Options() CommandStoreOptions

	// String returns a string representation of the command store.
	String() string

	// Info provides detailed information about the command store.
	Info(ctx context.Context) (*CommandStoreInfoModel, error)

	// Reset clears all commands from the store.
	Reset(ctx context.Context) error
}

Options and Methods

Init

The Init method initializes the command store with configuration options, such as read-only mode or logging level. This step ensures the store is properly configured for the specific use case.

Options	Description
CommandStoreOptionWithReadOnly(readOnly bool)	Specifies whether the store is read-only.
CommandStoreOptionWithAttribute(keys string, value any)	Sets custom attributes for the command store.
CommandStoreOptionWithCryptoService(cryptoService *comby.CryptoService)	Sets the crypto service for the command store to use.

Create

The Create method enables the addition of new commands to the store.

Options	Description
CommandStoreCreateOptionWithCommand(cmd Command)	Specifies the command to be added.
CommandStoreCreateOptionWithAttribute(keys string, value any)	Sets custom attributes for the Create option.

Get

Commands can be fetched individually using Get method.

Options	Description
CommandStoreGetOptionWithCommandUuid(commandUuid string)	Retrieves the specific command by its UUID.
CommandStoreGetOptionWithAttribute(keys string, value any)	Sets custom attributes for the Get option.

List

Commands can be fetched in bulk using List, with support for filtering and pagination.

Options	Description
CommandStoreListOptionWithTenantUuid(tenantUuid string)	Filters commands by tenant UUID.
CommandStoreListOptionWithDomain(domain string)	Filters commands by domain.
CommandStoreListOptionWithSessionUuid(sessionUuid string)	Filters commands by session UUID.
CommandStoreListOptionWithDataType(dataType string)	Filters commands by data type (=type as string of the domain command).
CommandStoreListOptionBefore(unixTimestamp int64)	Filters commands created before the specified timestamp.
CommandStoreListOptionAfter(unixTimestamp int64)	Filters commands created after the specified timestamp.
CommandStoreListOptionOffset(offset int64)	Sets the offset for pagination.
CommandStoreListOptionLimit(limit int64)	Sets the limit for pagination.
CommandStoreListOptionOrderBy(orderBy string)	Sets the field to order the commands by.
CommandStoreListOptionAscending(ascending bool)	Sets the sorting order (ascending or descending).
CommandStoreListOptionWithAttribute(keys string, value any)	Sets custom attributes for the List object.

Update

The Update method allows updates to existing commands.

Options	Description
CommandStoreWriteOptionWithCommand(cmd Command)	Specifies the commands to be updated.
CommandStoreUpdateOptionWithAttribute(keys string, value any)	Sets custom attributes for the Update object.

Delete

Commands can be removed using the Delete method.

Options	Description
CommandStoreDeleteOptionWithCommandUuid(commandUuid string)	Specifies the UUID of the command to delete.
CommandStoreDeleteOptionWithAttribute(keys string, value any)	Sets custom attributes for the Delete object.

Total

Retrieves the total count of commands in the store.

Close

Gracefully closes the connection to the command store.

Options

Returns the configuration options of the command store.

String

Returns a string representation of the command store.

Info

Returns metadata about the store, such as the type of store, number of commands, and connection details. Details are returned in the following structure:

type CommandStoreInfoModel struct {
	StoreType         string `json:"storeType"`         // Type of the command store.
	LastItemCreatedAt int64  `json:"lastItemCreatedAt"` // Timestamp of the last created command.
	NumItems          int64  `json:"numItems"`          // Number of commands in the store.
	ConnectionInfo    string `json:"connectionInfo"`    // Connection details of the command store.
}

Reset

Clears all commands from the store, providing a clean slate for testing or initialization.

Extensibility and Implementation

comby provides the following default implementations of the CommandStore interface:

• In-Memory Store: Useful for testing and development, offering fast and transient command storage. Used by default if no specific store is configured.
• SQLite Store: A lightweight, file-based implementation suitable for small to medium-sized applications. The underlying used driver is modernc.org/sqlite which means the comby retains CGo-free. Link: https://github.com/gradientzero/comby-store-sqlite
• PostgreSQL Store: A robust, production-ready implementation leveraging PostgreSQL as the backend. The underlying used driver is lib/pq. Link: https://github.com/gradientzero/comby-store-postgres

Users can implement the CommandStore interface to integrate with alternative storage systems, such as:

• NoSQL databases (e.g., MongoDB, DynamoDB).
• Distributed log systems (e.g., Apache Kafka, Pulsar).
• Cloud-native solutions (e.g., AWS S3, Google Cloud Firestore).

To create a custom command store, implement all methods in the interface, adhering to the specified contracts for behavior and parameters.