From 65274ed4377b178a2eec7cad3179bec6a0a7caf1 Mon Sep 17 00:00:00 2001 From: Brian H Date: Thu, 13 Jun 2024 11:31:59 -0600 Subject: [PATCH] Spin Build Targets Check SIP Signed-off-by: Brian H --- .../sips/0XX-spin-build-targets-check.md | 65 +++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 docs/content/sips/0XX-spin-build-targets-check.md diff --git a/docs/content/sips/0XX-spin-build-targets-check.md b/docs/content/sips/0XX-spin-build-targets-check.md new file mode 100644 index 000000000..683e13770 --- /dev/null +++ b/docs/content/sips/0XX-spin-build-targets-check.md @@ -0,0 +1,65 @@ +title = "SIP 0XX - Spin Build Targets Check" +template = "main" +date = "2024-06-13T12:00:00Z" +--- +Summary: Extend `spin build` to validate component targets against trigger types. + +Owner(s): + [brian.hardock@fermyon.com](mailto:brian.hardock@fermyon.com) + [michelle@fermyon.com](mailto:michelle@fermyon.com) + +Created: June 13, 2024 + +# Background +When associating a Spin component to a specific trigger in the Spin manifest, there is an implied world that the Spin component is targeting (e.g. the http trigger type implies `fermyon:spin/http-trigger`). However, we don't know if the Spin component actually implements that world until instantiation time (i.e. when a request / event comes in). + +As a visual example, if a user mistankenly associates an http trigger with a component that targeted the redis world: + +`examples/hello-world/spin.toml:` +```examples/hello-world/spin.toml +[[trigger.http]] +route = "/hello" +component = "hello" + +[component.hello] +source = "redis-component.wasm" # this is a redis component which is wrong +``` + +When issuing a curl to this endpoint: +``` +❯ curl -i http://127.0.0.1:3000/hello +HTTP/1.1 500 Internal Server Error +content-length: 0 +date: Tue, 04 Jun 2024 21:53:41 GMT +``` + +And in the output of `spin up` we see: +``` +❯ spin up -f examples/hello-world +Logging component stdio to "examples/hello-world/.spin/logs/" + +Serving http://127.0.0.1:3000 +Available Routes: + hello: http://127.0.0.1:3000/hello + A simple component that returns hello. +2024-06-04T21:53:16.160773Z ERROR spin_trigger_http: Error processing request: Expected component to either export `wasi:http/incoming-handler@0.2.0-rc-2023-10-18` or `fermyon:spin/inbound-http` but it exported neither +``` + +# Proposal + +Validate that each Spin component structurally conforms to (or targets) the expected world implied by the associated trigger type at build time rather than runtime. + +Prior art for performing a structural target of components against a world is [`wasm-tools component targets ...`](https://github.com/bytecodealliance/wasm-tools/blob/9340ed2466a50b4dbc580b13ba18a417dee91433/src/bin/wasm-tools/component.rs#L683) subcommand. We could potentially use [wac target predicate implemtation](https://github.com/bytecodealliance/wac/blob/4c96def294e6e779c52cfc5a93e05ed4c73ee60f/crates/wac-parser/src/resolution.rs#L2708) for a cleaner more actionable user diagnostic. Effectively, spin build could invoke the targets check using the trigger implied world and the source component. + +An "approximate" visual for the spin build experience we could enable: + +``` +❯ spin build -f examples/hello-world +Component "hello" is not a valid http component. + +Error: + Expected component to either export `wasi:http/incoming-handler@0.2.0-rc-2023-10-18` or `fermyon:spin/inbound-http` but it exported neither +``` + +# Open question: How does this work with custom triggers? +One possible solution is to allow trigger extensions the abilitiy to hook into build time validation via the `TriggerExecutor` trait. For each `spin build`, the `spin-cli` could construct a `build` command to invoke each trigger with allowing the custom trigger an opportunity to enforce validation on the target of each component before `up`.