From 08bf38d4841cfe5a5c91eef85b60e7719f3bd864 Mon Sep 17 00:00:00 2001
From: Alexander Weiss <alex@weissfam.de>
Date: Fri, 30 Jun 2023 16:21:01 +0200
Subject: [PATCH] rest/rclone: make # of retries cusomizable and use sensible
 default

---
 changelog/new.txt                      |  1 +
 config/full.toml                       |  2 +-
 crates/rustic_core/src/backend/rest.rs | 62 +++++++++++++++-----------
 3 files changed, 37 insertions(+), 28 deletions(-)

diff --git a/changelog/new.txt b/changelog/new.txt
index 7211335c3..f60a6c6e0 100644
--- a/changelog/new.txt
+++ b/changelog/new.txt
@@ -4,6 +4,7 @@ Breaking changes:
 
 Bugs fixed:
 - prune did abort when no time was set for a pack-do-delete. This case is now handled correctly.
+- retrying backend access didn't work for long operations. This has been fixed (and retries are now customizable)
 
 New features:
 - New global configuration paths are available, located at /etc/rustic/*.toml or %PROGRAMDATA%/rustic/config/*.toml, depending on your platform.
diff --git a/config/full.toml b/config/full.toml
index f0181f42a..8f692ca7e 100644
--- a/config/full.toml
+++ b/config/full.toml
@@ -33,7 +33,7 @@ warm-up-wait = "10min" # Default: not set
 [repository.options]
 post-create-command = "par2create -qq -n1 -r5 %file" # Only local backend; Default: not set
 post-delete-command = "sh -c \"rm -f %file*.par2\"" # Only local backend; Default: not set 
-retry = "true" # Only rest/rclone backend
+retry = "5" # Only rest/rclone backend; Allowed values: "false" or number of retries
 timeout = "10min" # Only rest/rclone backend
 
 # Snapshot-filter options: These options apply to all commands that use snapshot filters
diff --git a/crates/rustic_core/src/backend/rest.rs b/crates/rustic_core/src/backend/rest.rs
index 6e963de4a..740200376 100644
--- a/crates/rustic_core/src/backend/rest.rs
+++ b/crates/rustic_core/src/backend/rest.rs
@@ -38,19 +38,37 @@ impl CheckError for Response {
 }
 
 #[derive(Clone, Debug)]
-struct MaybeBackoff(Option<ExponentialBackoff>);
+struct LimitRetryBackoff {
+    max_retries: usize,
+    retries: usize,
+    exp: ExponentialBackoff,
+}
+
+impl Default for LimitRetryBackoff {
+    fn default() -> Self {
+        Self {
+            max_retries: 0,
+            retries: 0,
+            exp: ExponentialBackoffBuilder::new()
+                .with_max_elapsed_time(None) // no maximum elapsed time; we count number of retires
+                .build(),
+        }
+    }
+}
 
-impl Backoff for MaybeBackoff {
+impl Backoff for LimitRetryBackoff {
     fn next_backoff(&mut self) -> Option<Duration> {
-        self.0
-            .as_mut()
-            .and_then(backoff::backoff::Backoff::next_backoff)
+        self.retries += 1;
+        if self.retries > self.max_retries {
+            None
+        } else {
+            self.exp.next_backoff()
+        }
     }
 
     fn reset(&mut self) {
-        if let Some(b) = self.0.as_mut() {
-            b.reset();
-        }
+        self.retries = 0;
+        self.exp.reset();
     }
 }
 
@@ -58,7 +76,7 @@ impl Backoff for MaybeBackoff {
 pub struct RestBackend {
     url: Url,
     client: Client,
-    backoff: MaybeBackoff,
+    backoff: LimitRetryBackoff,
 }
 
 fn notify(err: reqwest::Error, duration: Duration) {
@@ -88,11 +106,7 @@ impl RestBackend {
         Ok(Self {
             url,
             client,
-            backoff: MaybeBackoff(Some(
-                ExponentialBackoffBuilder::new()
-                    .with_max_elapsed_time(Some(Duration::from_secs(600)))
-                    .build(),
-            )),
+            backoff: LimitRetryBackoff::default(),
         })
     }
 
@@ -126,19 +140,13 @@ impl ReadBackend for RestBackend {
 
     fn set_option(&mut self, option: &str, value: &str) -> RusticResult<()> {
         if option == "retry" {
-            match value {
-                "true" => {
-                    self.backoff = MaybeBackoff(Some(
-                        ExponentialBackoffBuilder::new()
-                            .with_max_elapsed_time(Some(Duration::from_secs(120)))
-                            .build(),
-                    ));
-                }
-                "false" => {
-                    self.backoff = MaybeBackoff(None);
-                }
-                val => return Err(RestErrorKind::NotSupportedForRetry(val.into()).into()),
-            }
+            let max_retries = if value == "false" {
+                0
+            } else {
+                usize::from_str(value)
+                    .map_err(|_| RestErrorKind::NotSupportedForRetry(value.into()))?
+            };
+            self.backoff.max_retries = max_retries;
         } else if option == "timeout" {
             let timeout = match humantime::Duration::from_str(value) {
                 Ok(val) => val,