Outbound HTTP to same app fails

[itowlson]

Run:

spin up --build -f examples/http-outbound/

and click on the outbound-http-to-same-app: http://127.0.0.1:3000/outbound-to-hello-component link. The page returns an error and the following trace at the console:

2024-02-22T23:31:01.830361Z ERROR spin_trigger_http: Error processing request: guest invocation failed

Caused by:
    0: error while executing at wasm backtrace:
           0: 0x221c6c - wit-component:shim!indirect-wasi:http/[email protected]
           1: 0xb580 - <unknown>!spin_sdk::wit::wasi::http::outgoing_handler::handle::hcd174f5b556efe06
           2: 0x102c6 - <unknown>!spin_sdk::http::executor::outgoing_request_send::h9d5498ce413021b0
           3: 0x3e10 - <unknown>!spin_sdk::http::executor::run::h46e24987e994c893
           4: 0x7af3 - <unknown>!wasi:http/[email protected]#handle
       note: using the `WASMTIME_BACKTRACE_DETAILS=1` environment variable may show more debugging information
    1: ErrorCode::HttpRequestUriInvalid

[dicej]

I started digging into this, adding a debug print statement to the outgoing_handler::Host::handle function in wasmtime-wasi-http. With spin-sdk 2.2.0, it works, and I see this:

req method Method::Get path Some(Scheme::Https) scheme Some("/hello") authority Some(":443")

With spin-sdk 3.0.0-pre0, it fails with the error Ivan posted above, and I see this:

req method Method::Get path Some(Scheme::Https) scheme Some("/hello") authority None

I'm guessing something subtle changed with the WASI 0.2.0 upgrade. I'll try to track it down.

[dicej]

Okay, I figured it out. When the SDK was targeting WASI 0.2.0-rc-2023-10-18, we implicitly relied on https://github.com/fermyon/spin/blob/78f84e7fc8f19c3a516de2395a399332b6889d67/crates/core/src/wasi_2023_10_18.rs#L1893-L1896 to fill in the authority field. Now that we're targeting 0.2.0, that code isn't run anymore, so we have to handle it in the SDK instead of in the host. I'll post a PR shortly.