Module axum_adapter 

Axum framework integration for A2A servers.

Provides A2aRouter, which builds an axum::Router that handles all A2A v1.0 methods using the existing RequestHandler.

Quick start

use std::sync::Arc;
use a2a_protocol_server::dispatch::axum_adapter::A2aRouter;
use a2a_protocol_server::RequestHandlerBuilder;

let handler = Arc::new(
    RequestHandlerBuilder::new(MyExecutor)
        .build()
        .expect("build handler"),
);

let app = A2aRouter::new(handler).into_router();

let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.unwrap();
axum::serve(listener, app).await.unwrap();

Composability

The returned router can be merged with other Axum routes, middleware, and layers:

let app = axum::Router::new()
    .merge(A2aRouter::new(handler).into_router())
    .layer(tower_http::cors::CorsLayer::permissive())
    .route("/custom", get(custom_handler));

Multi-tenancy: use a resolver, not the URL prefix

This router registers no /tenants/{tenant}/… routes, unlike the built-in REST dispatcher (crate::dispatch::rest), which strips that prefix and threads the tenant through. Requests to a tenant-prefixed path therefore 404 here — fail-safe, but surprising if you are porting from serve(), where the same URL works.

Tenancy itself is not lost. This router forwards request headers to the handler, so a configured TenantResolver — for example HeaderTenantResolver — resolves tenants normally, and the resolver is authoritative over any client-supplied value. Pair it with require_resolved_tenant so a request that carries no tenant is rejected rather than served from the shared default partition.

With no resolver configured, every request through this router is served from the default ("") tenant, because the per-request tenant field is not populated from the URL. That is correct for single-tenant deployments and is the reason the prefix is absent rather than silently mis-parsed; it is called out here so it is a choice rather than a discovery.

Structs

A2aRouter

Builder for an Axum Router that serves all A2A v1.0 protocol methods.