OpenStack API bindings (SDK)

Every platform API requires SDK bindings to various programming languages. OpenStack API bindings for Rust are not an exception. The OpenStack comes with openstack_sdk crate providing an SDK with both synchronous and asynchronous interfaces.

API bindings are generated from the OpenAPI specs of corresponding services. That means that those are only wrapping the API and usually not providing additional convenience features. The major benefit is that no maintenance efforts are required for the code being generated. Once OpenStack service updates OpenAPI spec for the integrated resources the changes would be immediately available on the next regeneration.

Features

• Sync and Async interface
• Query, Find and Pagination interfaces implementing basic functionality
• RawQuery interface providing more control over the API invocation with upload and download capabilities.
• Every combination of URL + http method + body schema is represented by a dedicated module
• User is in charge of return data schema.

Structure

Every single API call is represented by a dedicated module with a structure implementing REST Endpoint interface. That means that a GET operation is a dedicated implementation compared to a POST operation. Like described in the Structure document every RPC-like action and every microversion is implemented with a single module.

Using

The simplest example demonstrating how to list compute flavors:

use openstack_sdk::api::{paged, Pagination, QueryAsync};
use openstack_sdk::{AsyncOpenStack, config::ConfigFile, OpenStackError};
use openstack_sdk::types::ServiceType;
use openstack_sdk::api::compute::v2::flavor::list;

async fn list_flavors() -> Result<(), OpenStackError> {
    // Get the builder for the listing Flavors Endpoint
    let mut ep_builder = list::Request::builder();
    // Set the `min_disk` query param
    ep_builder.min_disk("15");
    let ep = ep_builder.build().unwrap();

    let cfg = ConfigFile::new().unwrap();
    // Get connection config from clouds.yaml/secure.yaml
    let profile = cfg.get_cloud_config("devstack".to_string()).unwrap().unwrap();
    // Establish connection
    let mut session = AsyncOpenStack::new(&profile).await?;

    // Invoke service discovery when desired.
    session.discover_service_endpoint(&ServiceType::Compute).await?;

    // Execute the call with pagination limiting maximum amount of entries to 1000
    let data: Vec<serde_json::Value> = paged(ep, Pagination::Limit(1000))
        .query_async(&session)
        .await.unwrap();

    println!("Data = {:?}", data);
    Ok(())
}

Documentation

Current crate documentation is known to be very poor. It will be addressed in future, but for now the best way to figure out how it works is to look at openstack_cli and openstack_tui using it.

Crate documentation is published here

Project documentation is available here