Apache OpenDAL™ Core

opendal-core contains the storage abstraction, operator APIs, extension traits, and shared infrastructure used by Apache OpenDAL™.

Most applications should depend on the opendal facade. The facade re-exports the core APIs and wires optional service, layer, executor, and HTTP transport crates behind feature flags.

Depend on opendal-core directly when implementing an OpenDAL service or layer, building a minimal integration from the split crates, or managing service registration and HTTP transport explicitly.

Quick start

The in-memory service is always available:

cargo add opendal-core

use opendal_core::services;
use opendal_core::Operator;
use opendal_core::Result;

fn build_operator() -> Result<Operator> {
    Operator::new(services::Memory::default())
}

Storage services and optional layers live in separate opendal-service-* and opendal-layer-* crates. Applications using the facade can enable them through services-* and layers-* features instead.

Compose split crates

Applications that depend on opendal-core directly compose storage and runtime behavior explicitly:

A service crate exports a builder that implements opendal_core::Builder. Pass the configured builder to Operator::new.
A layer crate exports a type that implements opendal_core::raw::Layer. Pass the configured layer to Operator::layer.
An HTTP transport crate exports an opendal_core::HttpTransport implementation. Wrap it in HttpTransporter and place it in the operator's OperationContext.

For example, the following dependencies compose S3, retry, and the reqwest HTTP transport without the opendal facade:

cargo add opendal-core opendal-service-s3 opendal-layer-retry
cargo add opendal-http-transport-reqwest

use opendal_core::HttpTransporter;
use opendal_core::OperationContext;
use opendal_core::Operator;
use opendal_core::Result;
use opendal_http_transport_reqwest::ReqwestTransport;
use opendal_layer_retry::RetryLayer;
use opendal_service_s3::S3;

fn build_operator(builder: S3) -> Result<Operator> {
    let context = OperationContext::new()
        .with_http_transport(HttpTransporter::new(ReqwestTransport::default()));

    Ok(Operator::new(builder)?
        .with_context(context)
        .layer(RetryLayer::default()))
}

Configure builder for the target S3-compatible service before passing it to build_operator.

Operator::new uses the builder directly and does not require service registration. Call the service crate's register_*_service function with OperatorRegistry::get() only when using scheme-driven construction through Operator::from_uri or Operator::via_iter.

Documentation

License

Licensed under the Apache License, Version 2.0.