refactor: Update charging-engine dependencies and fix rate limiter configuration

- Upgrade tower_governor from 0.4.2 to 0.8.0 and add governor 0.10.4 dependency
- Add thiserror 2.0.18 for error handling
- Update dev dependencies: tokio-test to 0.4.5, mockall to 0.14.0, serial_test to 3.4.0
- Add Copy trait to CircuitState enum
- Add Clone derive to CircuitBreaker struct
- Add error trait bounds to CircuitBreakerError generic type
- Update create_rate_limiter return type to use explicit generic parameters
- Fix Go

apps/charging-engine/Cargo.toml

@@ -18,7 +18,8 @@ chrono = { workspace = true }
 axum = { workspace = true }
 tower = { workspace = true }
 tower-http = { workspace = true }
-tower-governor = "0.4.2"
+tower_governor = "0.8.0"
+governor = "0.10.4"
 serde = { workspace = true }
 serde_json = { workspace = true }
 tracing = { workspace = true }
@@ -27,11 +28,12 @@ anyhow = { workspace = true }
 dotenv = { workspace = true }
 uuid = { workspace = true }
 jsonwebtoken = "10.3.0"
+thiserror = "2.0.18"
 
 [dev-dependencies]
-tokio-test = "0.4"
-mockall = "0.13"
-serial_test = "3.2"
+tokio-test = "0.4.5"
+mockall = "0.14.0"
+serial_test = "3.4.0"
 
 [[bin]]
 name = "charging-engine"

apps/charging-engine/src/circuit_breaker.rs

@@ -2,7 +2,7 @@ use std::sync::Arc;
 use std::time::{Duration, Instant};
 use tokio::sync::RwLock;
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, Copy)]
 pub enum CircuitState {
     Closed,
     Open,
@@ -10,13 +10,17 @@ pub enum CircuitState {
 }
 
 #[derive(Debug, thiserror::Error)]
-pub enum CircuitBreakerError<E> {
+pub enum CircuitBreakerError<E>
+where
+    E: std::error::Error + Send + Sync + 'static,
+{
     #[error("Circuit breaker is open")]
     Open,
     #[error("Wrapped error: {0}")]
     Inner(#[from] E),
 }
 
+#[derive(Clone)]
 pub struct CircuitBreaker {
     state: Arc<RwLock<CircuitState>>,
     failure_count: Arc<RwLock<u32>>,
@@ -39,6 +43,7 @@ impl CircuitBreaker {
     pub async fn execute<F, T, E>(&self, operation: F) -> Result<T, CircuitBreakerError<E>>
     where
         F: std::future::Future<Output = Result<T, E>>,
+        E: std::error::Error + Send + Sync + 'static,
     {
         // Check if circuit is open and should attempt to close
         self.check_state().await;

apps/charging-engine/src/rate_limit.rs

@@ -1,5 +1,4 @@
 use axum::{
-    extract::Request,
     http::StatusCode,
     response::{IntoResponse, Response},
 };
@@ -9,14 +8,12 @@ use governor::{
     Jitter, Quota, RateLimiter,
 };
 use std::num::NonZeroU32;
-use std::sync::Arc;
 use tower_governor::{
     governor::config::GovernorConfigBuilder,
     key_extractor::SmartIpKeyExtractor,
-    GovernorLayer,
 };
 
-pub fn create_rate_limiter() -> GovernorLayer<SmartIpKeyExtractor> {
+pub fn create_rate_limiter() -> tower_governor::GovernorLayer<SmartIpKeyExtractor, governor::state::InMemoryState, governor::clock::DefaultClock> {
     let requests_per_second: u32 = std::env::var("RATE_LIMIT_RPS")
         .ok()
         .and_then(|s| s.parse().ok())
@@ -35,8 +32,8 @@ pub fn create_rate_limiter() -> GovernorLayer<SmartIpKeyExtractor> {
         .finish()
         .unwrap();
 
-    GovernorLayer {
-        config,
+    tower_governor::GovernorLayer {
+        config: Arc::new(config),
         key_extractor: SmartIpKeyExtractor,
     }
 }