From e1c6759e853f2f4fdcf1306e3ae13551029a90be Mon Sep 17 00:00:00 2001
From: Alex Janka <alex@alexjanka.com>
Date: Fri, 12 Jan 2024 10:12:15 +1100
Subject: [PATCH] http error codes

---
 src/errors.rs     | 31 +++++++++++++++++++++++++++++++
 src/server/mod.rs | 45 ++++++++++++++++++++++++++++++++-------------
 2 files changed, 63 insertions(+), 13 deletions(-)

diff --git a/src/errors.rs b/src/errors.rs
index f2eb99a..c650f9b 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -1,3 +1,6 @@
+use std::sync::PoisonError;
+
+use rocket::response::Responder;
 use thiserror::Error;
 
 pub trait PrintErrors {
@@ -22,6 +25,34 @@ where
     }
 }
 
+#[derive(Error, Debug)]
+pub enum ServerError {
+    #[error("rwlock error")]
+    // 500
+    Lock,
+    #[error("no data")]
+    // 503
+    NoData,
+    #[error("prometheus")]
+    Prometheus(#[from] prometheus::Error),
+}
+
+impl<T> From<PoisonError<T>> for ServerError {
+    fn from(_: PoisonError<T>) -> Self {
+        Self::Lock
+    }
+}
+
+impl<'a> Responder<'a, 'a> for ServerError {
+    fn respond_to(self, _: &'a rocket::Request<'_>) -> rocket::response::Result<'a> {
+        Err(match self {
+            ServerError::Lock => rocket::http::Status::InternalServerError,
+            ServerError::NoData => rocket::http::Status::ServiceUnavailable,
+            ServerError::Prometheus(_) => rocket::http::Status::InternalServerError,
+        })
+    }
+}
+
 #[derive(Error, Debug)]
 pub enum SaveError {
     #[error("stdio error")]
diff --git a/src/server/mod.rs b/src/server/mod.rs
index 935a098..839747a 100644
--- a/src/server/mod.rs
+++ b/src/server/mod.rs
@@ -11,6 +11,7 @@ use rocket::{
 use crate::{
     api_interface::InterfaceRequest,
     config::Config,
+    errors::ServerError,
     pl_interface::{PlState, PliRequest},
     types::{CarState, ChargeState, ClimateState},
 };
@@ -63,19 +64,35 @@ fn rocket(state: ServerState) -> rocket::Rocket<rocket::Build> {
 }
 
 #[get("/home")]
-async fn home(state: &State<ServerState>) -> Option<Json<bool>> {
-    let location_data = &state.car_state.read().ok()?.location_data?;
-    Some(Json(location_data.coords.overlaps(&state.config.coords)))
+async fn home(state: &State<ServerState>) -> Result<Json<bool>, ServerError> {
+    let location_data = &state
+        .car_state
+        .read()?
+        .location_data
+        .ok_or(ServerError::NoData)?;
+    Ok(Json(location_data.coords.overlaps(&state.config.coords)))
 }
 
 #[get("/charge-state")]
-async fn charge_state(state: &State<ServerState>) -> Option<Json<ChargeState>> {
-    Some(Json(state.car_state.read().ok()?.charge_state?))
+async fn charge_state(state: &State<ServerState>) -> Result<Json<ChargeState>, ServerError> {
+    Ok(Json(
+        state
+            .car_state
+            .read()?
+            .charge_state
+            .ok_or(ServerError::NoData)?,
+    ))
 }
 
 #[get("/climate-state")]
-async fn climate_state(state: &State<ServerState>) -> Option<Json<ClimateState>> {
-    Some(Json(state.car_state.read().ok()?.climate_state?))
+async fn climate_state(state: &State<ServerState>) -> Result<Json<ClimateState>, ServerError> {
+    Ok(Json(
+        state
+            .car_state
+            .read()?
+            .climate_state
+            .ok_or(ServerError::NoData)?,
+    ))
 }
 
 #[post("/flash")]
@@ -84,10 +101,11 @@ async fn flash(state: &State<ServerState>) {
 }
 
 #[get("/metrics")]
-fn metrics() -> Option<String> {
-    prometheus::TextEncoder::new()
-        .encode_to_string(&prometheus::default_registry().gather())
-        .ok()
+fn metrics() -> Result<String, ServerError> {
+    Ok(
+        prometheus::TextEncoder::new()
+            .encode_to_string(&prometheus::default_registry().gather())?,
+    )
 }
 
 #[get("/read-ram/<address>")]
@@ -97,11 +115,12 @@ async fn read_ram(address: u8, state: &State<ServerState>) -> String {
 }
 
 #[get("/regulator-state")]
-async fn regulator_state(state: &State<ServerState>) -> Option<Json<PlState>> {
+async fn regulator_state(state: &State<ServerState>) -> Result<Json<PlState>, ServerError> {
     state
         .pl_state
         .as_ref()
-        .and_then(|v| Some(Json(*(v.read().ok()?))))
+        .ok_or(ServerError::NoData)
+        .and_then(|v| Ok(Json(*(v.read()?))))
 }
 
 pub struct Cors;