From fb860c52d26aa39d41764497eadad0e5ebd5e4f5 Mon Sep 17 00:00:00 2001
From: u5surf <u5.horie@gmail.com>
Date: Sat, 3 Oct 2020 06:33:57 +0900
Subject: [PATCH] Support exponential backoff in check_real #1

---
 src/checker.rs | 38 +++++++++++++++++++++++++++++++++-----
 1 file changed, 33 insertions(+), 5 deletions(-)

diff --git a/src/checker.rs b/src/checker.rs
index 71650f1..9ab6398 100644
--- a/src/checker.rs
+++ b/src/checker.rs
@@ -6,6 +6,7 @@ use hubcaps::{Credentials, Github};
 use regex::{Regex, RegexSet};
 use reqwest::header::{self, HeaderMap, HeaderValue};
 use std::{collections::HashSet, convert::TryFrom, time::Duration};
+use tokio::time::delay_for;
 use url::Url;
 
 pub(crate) enum RequestMethod {
@@ -163,10 +164,23 @@ impl Checker {
     }
 
     pub async fn check_real(&self, url: &Url) -> Status {
-        let status = self.check_normal(&url).await;
-        if status.is_success() {
-            return status;
-        }
+        let mut retries: i64 = 3;
+        let mut wait: u64 = 1;
+        let status = loop {
+            let res = self.check_normal(&url).await;
+            match res.is_success() {
+                true => return res,
+                false => {
+                    if retries > 0 {
+                        retries -= 1;
+                        delay_for(Duration::from_secs(wait)).await;
+                        wait *= 2;
+                    } else {
+                        break res;
+                    }
+                }
+            }
+        };
         // Pull out the heavy weapons in case of a failed normal request.
         // This could be a Github URL and we run into the rate limiter.
         if let Ok((owner, repo)) = self.extract_github(url.as_str()) {
@@ -262,7 +276,7 @@ impl Checker {
 mod test {
     use super::*;
     use http::StatusCode;
-    use std::time::Duration;
+    use std::time::{Duration, Instant};
     use url::Url;
     use wiremock::matchers::method;
     use wiremock::{Mock, MockServer, ResponseTemplate};
@@ -295,6 +309,20 @@ mod test {
         assert!(matches!(res, Status::Failed(_)));
     }
 
+    #[tokio::test]
+    async fn test_exponetial_backoff() {
+        let start = Instant::now();
+        let res = get_checker(false, HeaderMap::new())
+            .check(&Uri::Website(
+                Url::parse("https://endler.dev/abcd").unwrap(),
+            ))
+            .await;
+        let end = start.elapsed();
+
+        assert!(matches!(res, Status::Failed(_)));
+        assert!(matches!(end.as_secs(), 7));
+    }
+
     #[test]
     fn test_is_github() {
         assert_eq!(