From f5f72d7f2a02d3b9a0ea3bf6a5422755821ef127 Mon Sep 17 00:00:00 2001
From: Artyom Sidorenko <asidorenko@web3tech.ru>
Date: Wed, 23 Nov 2022 04:57:39 +0300
Subject: [PATCH] use arc-crutch to deal with borrowck

---
 wavesexchange_repos/Cargo.toml                |  1 +
 .../src/circuit_breaker/mod.rs                | 32 ++++++++++++-------
 2 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/wavesexchange_repos/Cargo.toml b/wavesexchange_repos/Cargo.toml
index 08e8b25..8dd2626 100644
--- a/wavesexchange_repos/Cargo.toml
+++ b/wavesexchange_repos/Cargo.toml
@@ -15,3 +15,4 @@ futures = "0.3.25"
 serde = { version = "1.0.147", features = ["derive"] }
 thiserror = "1.0.37"
 tokio = "1.22.0"
+wavesexchange_log = { path = "../wavesexchange_log" } 
diff --git a/wavesexchange_repos/src/circuit_breaker/mod.rs b/wavesexchange_repos/src/circuit_breaker/mod.rs
index cfef5b9..4ed0fad 100644
--- a/wavesexchange_repos/src/circuit_breaker/mod.rs
+++ b/wavesexchange_repos/src/circuit_breaker/mod.rs
@@ -10,11 +10,13 @@ pub mod error;
 
 pub use config::Config;
 pub use error::Error;
+use wavesexchange_log::debug;
 
 use std::{
     future::Future,
     mem::drop,
     num::NonZeroUsize,
+    sync::Arc,
     time::{Duration, Instant},
 };
 use tokio::sync::RwLock;
@@ -30,7 +32,7 @@ pub struct CircuitBreaker<S: FallibleDataSource> {
 }
 
 pub struct CBState<S: FallibleDataSource> {
-    data_source: S,
+    data_source: Arc<S>,
     err_count: usize, // current errors count
     first_err_ts: Option<Instant>,
 }
@@ -84,7 +86,7 @@ impl<S: FallibleDataSource> CircuitBreakerBuilder<S> {
 
         Ok(CircuitBreaker {
             state: RwLock::new(CBState {
-                data_source: init_fn(),
+                data_source: Arc::new(init_fn()),
                 err_count: 0,
                 first_err_ts: None,
             }),
@@ -108,32 +110,36 @@ impl<S: FallibleDataSource> CircuitBreaker<S> {
 
     pub async fn query<T, F, Fut>(&self, query_fn: F) -> Result<T, S::Error>
     where
-        F: Fn(&S) -> Fut,
+        //todo: figure out how to FnOnce(&S)
+        F: FnOnce(Arc<S>) -> Fut,
         Fut: Future<Output = Result<T, S::Error>>,
     {
-        let data_src_read_lock = &self.state.read().await.data_source;
-        let result = query_fn(&data_src_read_lock).await;
+        let state_read_lock = self.state.read().await;
+        let result = query_fn(state_read_lock.data_source.clone()).await;
 
         if let Err(e) = &result {
             if S::is_countable_err(e) {
-                drop(data_src_read_lock);
+                drop(state_read_lock);
                 let mut state = self.state.write().await;
                 state.err_count += 1;
+                debug!("err count: {}", state.err_count);
                 match state.first_err_ts {
-                    Some(ts) if ts.elapsed() <= self.max_timespan => {
+                    Some(ts) if ts.elapsed() > self.max_timespan => {
                         if state.err_count > self.max_err_count_per_timespan.get() {
-                            return Err(state.data_source.fallback());
+                            return Err(state
+                                .data_source
+                                .fallback(ts.elapsed().as_millis(), state.err_count));
                         }
                     }
                     None => state.first_err_ts = Some(Instant::now()),
                     _ => {}
                 }
                 if S::REINIT_ON_FAIL {
-                    state.data_source = (self.init_fn)();
+                    state.data_source = Arc::new((self.init_fn)());
                 }
             }
         } else {
-            drop(data_src_read_lock);
+            drop(state_read_lock);
             let mut state = self.state.write().await;
             state.err_count = 0;
             state.first_err_ts = None;
@@ -148,7 +154,9 @@ pub trait FallibleDataSource {
 
     fn is_countable_err(err: &Self::Error) -> bool;
 
-    fn fallback(&self) -> Self::Error {
-        panic!("Я ГОВОРЮ НЕ БЫЛО РАЗРЫВОВ СВЯЗИ! С НОЯБРЯ ПРОШЛОГО ГОДА! А СЕЙЧАС ЦЕЛЫХ ЧЕТЫРЕ РАЗРЫВА БЫЛО!")
+    fn fallback(&self, elapsed_ms: u128, err_count: usize) -> Self::Error {
+        panic!(
+            "CircuitBreaker panicked after {err_count} errors in a row happened in {elapsed_ms}ms"
+        )
     }
 }