aws-smithy-http-server - http/1 support

[drganjoo]

This PR migrates aws-smithy-http-server from http@0.x/hyper@0.14 to http@1.x/hyper@1.x.

Background

This is the second PR in the HTTP 1.x migration series:

1. ✅ Legacy crates PR - Added aws-smithy-legacy-http and aws-smithy-legacy-http-server for http@0.x support
2. 👉 This PR - Upgrade aws-smithy-http-server to http@1.x/hyper@1.x
3. 🔜 Codegen changes - Add http-1x flag and conditional dependency logic

Key Changes

1. Dependency Upgrades

• http: 0.2.9 → 1.x
• http-body: 0.4.5 → 1.0
• hyper: 0.14.26 → 1.x (with server, http1, http2 features)
• hyper-util: Added 0.1 for server utilities (server-auto, server-graceful, etc.)
• http-body-util: Added 0.1 for body utilities
• tower-http: 0.3 → 0.6
• lambda_http: 0.8.4 → 0.17 (for AWS Lambda support)

Updated aws-smithy-types to use http-body-1-x feature instead of http-body-0-4-x.

2. New serve Module

Added a comprehensive serve module (inspired by axum::serve) that provides:

• Simple server API: Ergonomic serve(listener, service) function
• Flexible listeners: Listener trait supporting TCP, Unix sockets, and custom transports
• Connection limiting: Built-in limit_connections() via ListenerExt
• Graceful shutdown: Zero-cost when unused, opt-in with .with_graceful_shutdown()
• Hyper customization: .configure_hyper() for protocol and performance tuning
• Comprehensive docs: Examples, troubleshooting, and advanced patterns

Files: src/serve/mod.rs (794 lines), src/serve/listener.rs (269 lines)

3. API Updates Throughout

Updated all modules to work with http@1.x APIs:

• body.rs: Enhanced to work with http-body@1.0 traits (+176 lines)
• routing/lambda_handler.rs: Updated for lambda_http@0.17 (+299 lines)
• layer/alb_health_check.rs: Adapted for new HTTP types (+150 lines)
• protocol modules: Updated all protocol implementations (REST JSON, AWS JSON, REST XML, RPC v2 CBOR)
• rejection/error types: Added implementations for http@1.x error types

4. Comprehensive Testing

• serve_integration_test.rs: 812 lines of integration tests for the serve module
• graceful_shutdown_test.rs: 211 lines testing graceful shutdown scenarios
• Tests verify HTTP/1, HTTP/2, connection limits, graceful shutdown, and error handling

Migration Impact

Breaking Change: This updates the public API to use http@1.x types (http::Request, http::Response, etc.).

Users will need to:

1. Update their dependencies to use http@1.x
2. Use the new serve() API or update to hyper@1.x connection APIs
3. Update any code working directly with HTTP types

Benefits

• Modern ecosystem: Aligns with the latest Rust HTTP ecosystem
• Better ergonomics: New serve module provides simpler server setup
• Performance: Benefits from hyper@1.x performance improvements
• Maintainability: No need to maintain compatibility with deprecated versions
• Feature completeness: Graceful shutdown, connection limiting, and flexible configuration

Testing

• ✅ Integration tests cover major scenarios
• ✅ Graceful shutdown tested
• ✅ All protocol implementations verified

Next Steps

The next PR will update the codegen to conditionally generate code that uses either:

• aws-smithy-legacy-http-server (for http@0.x - default)
• aws-smithy-http-server (for http@1.x - when http-1x flag enabled)

[rcoh]

huh...I wonder if we want an extension trait here or something more explicit.

[drganjoo]

It comes from ListenerExt imported at the top—happy to hear what you had in mind for making it more explicit.

[drganjoo]

On second thought, let's remove this example. Examples should focus specifically on demonstrating functionality that is related to aws-smithy-http-server rather than other types.

[rcoh]

I think you can cfg out the entire example? Or can you not because its an example and not a module?

[drganjoo]

We keep the example visible because users might try to run it without the feature flag. In that case, we print helpful guidance via eprintln!('cargo run --example request_id --features request-id'). Not everyone will know they need to enable the feature flag initially, so this provides better user experience.

[rcoh]

rust-runtime/cargo.lock is deleted which is presumably unintentional