Feat: Add 'log_error' attribute to allow errors to pass through inste…

…ad of triggering Worker Threw Exception (cloudflare#13)

* add log_error attribute

* added console logging and renamed attribute

Co-authored-by: Leo Orshansky <[email protected]>

macros/cf/src/lib.rs

@@ -2,21 +2,42 @@ extern crate wasm_bindgen_macro_support;
 
 use proc_macro::TokenStream;
 use quote::quote;
-use syn::{parse_macro_input, Ident, ItemFn};
+use syn::{Ident, ItemFn, parse_macro_input, punctuated::Punctuated, token::Comma};
 
 #[proc_macro_attribute]
 pub fn worker(attr: TokenStream, item: TokenStream) -> TokenStream {
-    let exit_missing_attr =
-        || panic!("must have either 'fetch' or 'scheduled' attribute, e.g. #[cf::worker(fetch)]");
-    if attr.is_empty() {
-        exit_missing_attr();
+    let attrs: Punctuated<Ident, Comma> = parse_macro_input!(attr with Punctuated::parse_terminated);
+
+    enum HandlerType {
+        Fetch,
+        Scheduled
+    }
+    use HandlerType::*;
+
+    let mut handler_type = None;
+    let mut respond_with_errors = false;
+
+    for attr in attrs {
+        match attr.to_string().as_str() {
+            "fetch" => {
+                handler_type = Some(Fetch)
+            }
+            "scheduled" => {
+                handler_type = Some(Scheduled)
+            }
+            "respond_with_errors" => {
+                respond_with_errors = true;
+            },
+            _ => panic!("Invalid attribute: {}", attr.to_string())
+        }
     }
+    let handler_type = handler_type.expect("must have either 'fetch' or 'scheduled' attribute, e.g. #[cf::worker(fetch)]");
 
     // create new var using syn item of the attributed fn
     let mut input_fn = parse_macro_input!(item as ItemFn);
 
-    match attr.to_string().as_str() {
-        "fetch" => {
+    match handler_type {
+        Fetch => {
             // TODO: validate the inputs / signature
             // let input_arg = input_fn.sig.inputs.first().expect("#[cf::worker(fetch)] attribute requires exactly one input, of type `worker::Request`");
 
@@ -26,13 +47,29 @@ pub fn worker(attr: TokenStream, item: TokenStream) -> TokenStream {
             // rename the original attributed fn
             input_fn.sig.ident = input_fn_ident.clone();
 
+            let error_handling = match respond_with_errors {
+                true => {
+                    quote! {
+                        Response::error(e.to_string(), 500).unwrap().into()
+                    }
+                },
+                false => {
+                    quote! { panic!("{}", e) }
+                }
+            };
+
             // create a new "main" function that takes the edgeworker_sys::Request, and calls the
             // original attributed function, passing in a converted worker::Request
             let wrapper_fn = quote! {
-                pub async fn #wrapper_fn_ident(req: ::edgeworker_sys::Request, env: ::worker::Env) -> ::worker::Result<::edgeworker_sys::Response> {
+                pub async fn #wrapper_fn_ident(req: ::edgeworker_sys::Request, env: ::worker::Env) -> ::edgeworker_sys::Response {
                     // get the worker::Result<worker::Response> by calling the original fn
-                    #input_fn_ident(worker::Request::from(req), env).await
-                        .map(edgeworker_sys::Response::from)
+                    match #input_fn_ident(worker::Request::from(req), env).await.map(edgeworker_sys::Response::from) {
+                        Ok(res) => res,
+                        Err(e) => {
+                            ::worker::prelude::console_log!("{}", &e);
+                            #error_handling
+                        }
+                    }
                 }
             };
             let wasm_bindgen_code =
@@ -47,7 +84,7 @@ pub fn worker(attr: TokenStream, item: TokenStream) -> TokenStream {
 
             TokenStream::from(output)
         }
-        "scheduled" => {
+        Scheduled => {
             // save original fn name for re-use in the wrapper fn
             let original_input_fn_ident = input_fn.sig.ident.clone();
             let output_fn_ident = Ident::new("glue_cron", input_fn.sig.ident.span());
@@ -72,7 +109,6 @@ pub fn worker(attr: TokenStream, item: TokenStream) -> TokenStream {
 
             TokenStream::from(output)
         }
-        _ => exit_missing_attr(),
     }
 }
 

rust-sandbox/src/lib.rs

@@ -34,7 +34,7 @@ fn handle_a_request(_req: Request, _env: Env, _params: Params) -> Result<Respons
     Response::ok("weeee")
 }
 
-#[cf::worker(fetch)]
+#[cf::worker(fetch, respond_with_errors)]
 pub async fn main(req: Request, env: Env) -> Result<Response> {
     utils::set_panic_hook();
 
@@ -111,13 +111,13 @@ pub async fn main(req: Request, env: Env) -> Result<Response> {
         ))
     })?;
 
-    router.on_async("/proxy_request/:url", |_req, _env, params| {
+    router.on_async("/proxy_request/*url", |_req, _env, params| {
         // Must copy the parameters into the heap here for lifetime purposes
-        let url = params.get("url").unwrap().to_string();
+        let url = params.get("url").unwrap().strip_prefix('/').unwrap().to_string();
         async move { Fetch::Url(&url).send().await }
     })?;
 
-    router.on_async("durable", |_req, e, _params| async move {
+    router.on_async("/durable", |_req, e, _params| async move {
         let namespace = e.get_binding::<ObjectNamespace>("COUNTER")?;
         let stub = namespace.id_from_name("A")?.get_stub()?;
         stub.fetch_with_str("/").await

worker/src/lib.rs

@@ -37,6 +37,7 @@ pub mod prelude {
     pub use crate::{Date, DateInit};
     pub use matchit::Params;
     pub use web_sys::RequestInit;
+    pub use edgeworker_sys::console_log;
 }
 
 #[derive(Debug)]