feat(api): implement PKError in rust-api

crates/api/Cargo.toml

@@ -5,6 +5,7 @@ edition = "2021"
 
 [dependencies]
 pluralkit_models = { path = "../models" }
+pk_macros = { path = "../macros" }
 libpk = { path = "../libpk" }
 
 anyhow = { workspace = true } 

crates/api/src/endpoints/private.rs

@@ -2,6 +2,7 @@ use crate::ApiContext;
 use axum::{extract::State, response::Json};
 use fred::interfaces::*;
 use libpk::state::ShardState;
+use pk_macros::api_endpoint;
 use serde::Deserialize;
 use serde_json::{json, Value};
 use std::collections::HashMap;
@@ -13,34 +14,33 @@ struct ClusterStats {
     pub channel_count: i32,
 }
 
+#[api_endpoint]
 pub async fn discord_state(State(ctx): State<ApiContext>) -> Json<Value> {
     let mut shard_status = ctx
         .redis
         .hgetall::<HashMap<String, String>, &str>("pluralkit:shardstatus")
-        .await
-        .unwrap()
+        .await?
         .values()
         .map(|v| serde_json::from_str(v).expect("could not deserialize shard"))
         .collect::<Vec<ShardState>>();
 
     shard_status.sort_by(|a, b| b.shard_id.cmp(&a.shard_id));
 
-    Json(json!({
+    Ok(Json(json!({
         "shards": shard_status,
-    }))
+    })))
 }
 
+#[api_endpoint]
 pub async fn meta(State(ctx): State<ApiContext>) -> Json<Value> {
     let stats = serde_json::from_str::<Value>(
         ctx.redis
             .get::<String, &'static str>("statsapi")
-            .await
-            .unwrap()
+            .await?
             .as_str(),
-    )
-    .unwrap();
+    )?;
 
-    Json(stats)
+    Ok(Json(stats))
 }
 
 use std::time::Duration;

crates/api/src/endpoints/system.rs

@@ -1,22 +1,18 @@
-use axum::{
-    extract::State,
-    http::StatusCode,
-    response::{IntoResponse, Response},
-    Extension, Json,
-};
-use serde_json::json;
+use axum::{extract::State, response::IntoResponse, Extension, Json};
+use pk_macros::api_endpoint;
+use serde_json::{json, Value};
 use sqlx::Postgres;
-use tracing::error;
 
 use pluralkit_models::{PKSystem, PKSystemConfig, PrivacyLevel};
 
-use crate::{auth::AuthState, util::json_err, ApiContext};
+use crate::{auth::AuthState, error::fail, ApiContext};
 
+#[api_endpoint]
 pub async fn get_system_settings(
     Extension(auth): Extension<AuthState>,
     Extension(system): Extension<PKSystem>,
     State(ctx): State<ApiContext>,
-) -> Response {
+) -> Json<Value> {
     let access_level = auth.access_level_for(&system);
 
     let mut config = match sqlx::query_as::<Postgres, PKSystemConfig>(
@@ -27,23 +23,11 @@ pub async fn get_system_settings(
     .await
     {
         Ok(Some(config)) => config,
-        Ok(None) => {
-            error!(
-                system = system.id,
-                "failed to find system config for existing system"
-            );
-            return json_err(
-                StatusCode::INTERNAL_SERVER_ERROR,
-                r#"{"message": "500: Internal Server Error", "code": 0}"#.to_string(),
-            );
-        }
-        Err(err) => {
-            error!(?err, "failed to query system config");
-            return json_err(
-                StatusCode::INTERNAL_SERVER_ERROR,
-                r#"{"message": "500: Internal Server Error", "code": 0}"#.to_string(),
-            );
-        }
+        Ok(None) => fail!(
+            system = system.id,
+            "failed to find system config for existing system"
+        ),
+        Err(err) => fail!(?err, "failed to query system config"),
     };
 
     // fix this
@@ -51,7 +35,7 @@ pub async fn get_system_settings(
         config.name_format = Some("{name} {tag}".to_string());
     }
 
-    Json(&match access_level {
+    Ok(Json(match access_level {
         PrivacyLevel::Private => config.to_json(),
         PrivacyLevel::Public => json!({
             "pings_enabled": config.pings_enabled,
@@ -64,6 +48,5 @@ pub async fn get_system_settings(
             "proxy_switch": config.proxy_switch,
             "name_format": config.name_format,
         }),
-    })
-    .into_response()
+    }))
 }

crates/api/src/error.rs

@@ -1,13 +1,17 @@
-use axum::http::StatusCode;
+use axum::{
+    http::StatusCode,
+    response::{IntoResponse, Response},
+};
 use std::fmt;
 
-// todo
-#[allow(dead_code)]
+// todo: model parse errors
 #[derive(Debug)]
 pub struct PKError {
     pub response_code: StatusCode,
     pub json_code: i32,
     pub message: &'static str,
+
+    pub inner: Option<anyhow::Error>,
 }
 
 impl fmt::Display for PKError {
@@ -16,17 +20,67 @@ impl fmt::Display for PKError {
     }
 }
 
-impl std::error::Error for PKError {}
+impl Clone for PKError {
+    fn clone(&self) -> PKError {
+        if self.inner.is_some() {
+            panic!("cannot clone PKError with inner error");
+        }
+        PKError {
+            response_code: self.response_code,
+            json_code: self.json_code,
+            message: self.message,
+            inner: None,
+        }
+    }
+}
+
+impl<E> From<E> for PKError
+where
+    E: std::fmt::Display + Into<anyhow::Error>,
+{
+    fn from(err: E) -> Self {
+        let mut res = GENERIC_SERVER_ERROR.clone();
+        res.inner = Some(err.into());
+        res
+    }
+}
+
+impl IntoResponse for PKError {
+    fn into_response(self) -> Response {
+        if let Some(inner) = self.inner {
+            tracing::error!(?inner, "error returned from handler");
+        }
+        crate::util::json_err(
+            self.response_code,
+            serde_json::to_string(&serde_json::json!({
+                "message": self.message,
+                "code": self.json_code,
+            }))
+            .unwrap(),
+        )
+    }
+}
+
+macro_rules! fail {
+    ($($stuff:tt)+) => {{
+        tracing::error!($($stuff)+);
+        return Err(crate::error::GENERIC_SERVER_ERROR);
+    }};
+}
+
+pub(crate) use fail;
 
-#[allow(unused_macros)]
 macro_rules! define_error {
     ( $name:ident, $response_code:expr, $json_code:expr, $message:expr ) => {
-        const $name: PKError = PKError {
+        #[allow(dead_code)]
+        pub const $name: PKError = PKError {
             response_code: $response_code,
             json_code: $json_code,
             message: $message,
+            inner: None,
         };
     };
 }
 
-// define_error! { GENERIC_BAD_REQUEST, StatusCode::BAD_REQUEST, 0, "400: Bad Request" }
+define_error! { GENERIC_BAD_REQUEST, StatusCode::BAD_REQUEST, 0, "400: Bad Request" }
+define_error! { GENERIC_SERVER_ERROR, StatusCode::INTERNAL_SERVER_ERROR, 0, "500: Internal Server Error" }

crates/api/src/main.rs

@@ -4,8 +4,8 @@ use auth::{AuthState, INTERNAL_APPID_HEADER, INTERNAL_SYSTEMID_HEADER};
 use axum::{
     body::Body,
     extract::{Request as ExtractRequest, State},
-    http::{Response, StatusCode, Uri},
-    response::IntoResponse,
+    http::Uri,
+    response::{IntoResponse, Response},
     routing::{delete, get, patch, post},
     Extension, Router,
 };
@@ -13,7 +13,9 @@ use hyper_util::{
     client::legacy::{connect::HttpConnector, Client},
     rt::TokioExecutor,
 };
-use tracing::{error, info};
+use tracing::info;
+
+use pk_macros::api_endpoint;
 
 mod auth;
 mod endpoints;
@@ -30,11 +32,12 @@ pub struct ApiContext {
     rproxy_client: Client<HttpConnector, Body>,
 }
 
+#[api_endpoint]
 async fn rproxy(
     Extension(auth): Extension<AuthState>,
     State(ctx): State<ApiContext>,
     mut req: ExtractRequest<Body>,
-) -> Result<Response<Body>, StatusCode> {
+) -> Response {
     let path = req.uri().path();
     let path_query = req
         .uri()
@@ -59,15 +62,7 @@ async fn rproxy(
         headers.append(INTERNAL_APPID_HEADER, aid.into());
     }
 
-    Ok(ctx
-        .rproxy_client
-        .request(req)
-        .await
-        .map_err(|error| {
-            error!(?error, "failed to serve reverse proxy to dotnet-api");
-            StatusCode::BAD_GATEWAY
-        })?
-        .into_response())
+    Ok(ctx.rproxy_client.request(req).await?.into_response())
 }
 
 // this function is manually formatted for easier legibility of route_services

crates/macros/Cargo.toml

@@ -10,4 +10,5 @@ proc-macro = true
 quote = "1.0"
 proc-macro2 = "1.0"
 syn = "2.0"
+prettyplease = "0.2.36"
 

crates/macros/src/api.rs

@@ -0,0 +1,52 @@
+use quote::quote;
+use syn::{parse_macro_input, FnArg, ItemFn, Pat};
+
+fn pretty_print(ts: &proc_macro2::TokenStream) -> String {
+    let file = syn::parse_file(&ts.to_string()).unwrap();
+    prettyplease::unparse(&file)
+}
+
+pub fn macro_impl(
+    _args: proc_macro::TokenStream,
+    input: proc_macro::TokenStream,
+) -> proc_macro::TokenStream {
+    let input = parse_macro_input!(input as ItemFn);
+
+    let fn_name = &input.sig.ident;
+    let fn_params = &input.sig.inputs;
+    let fn_body = &input.block;
+    let syn::ReturnType::Type(_, fn_return_type) = &input.sig.output else {
+        panic!("handler return type must not be nothing");
+    };
+    let pms: Vec<proc_macro2::TokenStream> = fn_params
+        .iter()
+        .map(|v| {
+            let FnArg::Typed(pat) = v else {
+                panic!("must not have self param in handler");
+            };
+            let mut pat = pat.pat.clone();
+            if let Pat::Ident(ident) = *pat {
+                let mut ident = ident.clone();
+                ident.mutability = None;
+                pat = Box::new(Pat::Ident(ident));
+            }
+            quote! { #pat }
+        })
+        .collect();
+
+    let res = quote! {
+        #[allow(unused_mut)]
+        pub async fn #fn_name(#fn_params) -> axum::response::Response {
+            async fn inner(#fn_params) -> Result<#fn_return_type, crate::error::PKError> {
+                #fn_body
+            }
+
+            match inner(#(#pms),*).await {
+                Ok(res) => res.into_response(),
+                Err(err) => err.into_response(),
+            }
+        }
+    };
+
+    res.into()
+}

crates/macros/src/lib.rs

@@ -1,8 +1,14 @@
 use proc_macro::TokenStream;
 
+mod api;
 mod entrypoint;
 mod model;
 
+#[proc_macro_attribute]
+pub fn api_endpoint(args: TokenStream, input: TokenStream) -> TokenStream {
+    api::macro_impl(args, input)
+}
+
 #[proc_macro_attribute]
 pub fn main(args: TokenStream, input: TokenStream) -> TokenStream {
     entrypoint::macro_impl(args, input)