Backends Overview

OmniStorage supports multiple storage backends through a unified interface. Each backend implements the core Backend interface, and many also implement ExtendedBackend for additional capabilities.

Core Backends

These backends are included in omnistorage-core with minimal dependencies:

Backend	Package	Extended	Description
File	object/backend/file	Yes	Local filesystem
Memory	object/backend/memory	Yes	In-memory storage
SFTP	object/backend/sftp	Yes	SSH file transfer
Channel	object/backend/channel	No	Go channel for streaming

External Backends (Separate Packages)

Cloud backends with vendor SDKs are in separate repositories to keep the core lightweight:

Backend	Repository	Description
S3	omni-aws	AWS S3, R2, MinIO, Wasabi
DynamoDB	omni-aws	AWS DynamoDB (KVS)
Google Cloud Storage	omni-google	GCS
Google Drive	omni-google	Google Drive API
GitHub	omni-github	GitHub API storage

Backend Capabilities

Each backend has different capabilities:

Feature	File	Memory	SFTP	Channel
Read/Write	Yes	Yes	Yes	Yes
Stat	Yes	Yes	Yes	No
Copy	Yes	Yes	Yes	No
Move	Yes	Yes	Yes	No
Mkdir	Yes	Yes	Yes	No
Range Read	Yes	No	Yes	No
Streaming	Yes	Yes	Yes	Yes

Using the Registry

Backends register themselves automatically when imported:

import (
    "github.com/plexusone/omnistorage-core/object"

    // Side-effect imports register backends
    _ "github.com/plexusone/omnistorage-core/object/backend/file"
    _ "github.com/plexusone/omnistorage-core/object/backend/memory"
)

// Open by name
backend, err := object.Open("file", map[string]string{
    "root": "/data",
})

Configuration-Driven Selection

Select backends at runtime from configuration:

backendType := os.Getenv("STORAGE_BACKEND")
config := map[string]string{
    "root": os.Getenv("STORAGE_ROOT"),
}

backend, err := object.Open(backendType, config)

Implementing a Custom Backend

See Custom Backend Guide for how to implement your own backend.