From e9953165d3560aaa6e474e4f0977c53609ecf367 Mon Sep 17 00:00:00 2001
From: Roman Timushev <roman.timushev@coralogix.com>
Date: Thu, 27 Jun 2024 14:41:07 +0200
Subject: [PATCH] Cache lock improvements (#140)

1. Exponential backoff makes protofetch sometimes take too long to run.
2. It makes sense to initialize signal handlers to make sure the locks
are removed when protofetch is killed.
---
 Cargo.lock       | 53 ++++++++++++++++++++++++++++++++++++++++--------
 Cargo.toml       |  3 ++-
 src/git/cache.rs | 29 +++++++++++++++-----------
 3 files changed, 64 insertions(+), 21 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 99513b1..253c8dc 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -229,6 +229,19 @@ dependencies = [
  "typenum",
 ]
 
+[[package]]
+name = "dashmap"
+version = "5.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "978747c1d849a7d2ee5e8adc0159961c48fb7e5db2f06af6723b80123bb53856"
+dependencies = [
+ "cfg-if",
+ "hashbrown",
+ "lock_api",
+ "once_cell",
+ "parking_lot_core",
+]
+
 [[package]]
 name = "der"
 version = "0.7.8"
@@ -387,9 +400,9 @@ dependencies = [
 
 [[package]]
 name = "gix-features"
-version = "0.38.1"
+version = "0.38.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "db4254037d20a247a0367aa79333750146a369719f0c6617fec4f5752cc62b37"
+checksum = "ac7045ac9fe5f9c727f38799d002a7ed3583cd777e3322a7c4b43e3cf437dc69"
 dependencies = [
  "gix-hash",
  "gix-trace",
@@ -399,10 +412,11 @@ dependencies = [
 
 [[package]]
 name = "gix-fs"
-version = "0.10.2"
+version = "0.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2184c40e7910529677831c8b481acf788ffd92427ed21fad65b6aa637e631b8"
+checksum = "c3338ff92a2164f5209f185ec0cd316f571a72676bb01d27e22f2867ba69f77a"
 dependencies = [
+ "fastrand",
  "gix-features",
  "gix-utils",
 ]
@@ -419,9 +433,9 @@ dependencies = [
 
 [[package]]
 name = "gix-lock"
-version = "13.1.1"
+version = "14.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e7c359f81f01b8352063319bcb39789b7ea0887b406406381106e38c4a34d049"
+checksum = "e3bc7fe297f1f4614774989c00ec8b1add59571dc9b024b4c00acb7dedd4e19d"
 dependencies = [
  "gix-tempfile",
  "gix-utils",
@@ -430,14 +444,17 @@ dependencies = [
 
 [[package]]
 name = "gix-tempfile"
-version = "13.1.1"
+version = "14.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a761d76594f4443b675e85928e4902dec333273836bd386906f01e7e346a0d11"
+checksum = "d3b0e276cd08eb2a22e9f286a4f13a222a01be2defafa8621367515375644b99"
 dependencies = [
+ "dashmap",
  "gix-fs",
  "libc",
  "once_cell",
  "parking_lot",
+ "signal-hook",
+ "signal-hook-registry",
  "tempfile",
 ]
 
@@ -885,6 +902,7 @@ dependencies = [
  "env_logger",
  "git2",
  "gix-lock",
+ "gix-tempfile",
  "home",
  "log",
  "pretty_assertions",
@@ -1053,6 +1071,25 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "signal-hook"
+version = "0.3.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8621587d4798caf8eb44879d42e56b9a93ea5dcd315a6487c357130095b62801"
+dependencies = [
+ "libc",
+ "signal-hook-registry",
+]
+
+[[package]]
+name = "signal-hook-registry"
+version = "1.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a9e9e0b4211b72e7b8b6e85c807d36c212bdb33ea8587f7569562a84df5465b1"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "signature"
 version = "2.1.0"
diff --git a/Cargo.toml b/Cargo.toml
index cfc23ff..9d9911c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -21,7 +21,8 @@ clap = { version = "4.4.7", features = ["derive"] }
 config = { version = "0.13.3", default-features = false, features = ["toml"] }
 env_logger = { version = "0.10.0", default-features = false, features = ["auto-color"] }
 git2 = "0.18.1"
-gix-lock = "13.1.1"
+gix-lock = { version = "14.0.0" }
+gix-tempfile = { version = "14.0.0", features = ["signals"] }
 home = "0.5.5"
 log = "0.4.20"
 regex-lite = "0.1.5"
diff --git a/src/git/cache.rs b/src/git/cache.rs
index ec98075..5756e2b 100644
--- a/src/git/cache.rs
+++ b/src/git/cache.rs
@@ -1,6 +1,6 @@
 use std::{
     path::{Path, PathBuf},
-    time::Duration,
+    time::{Duration, Instant},
 };
 
 use git2::{
@@ -56,6 +56,7 @@ impl ProtofetchGitCache {
             std::fs::create_dir_all(&location)?;
         }
 
+        gix_lock::tempfile::signal::setup(Default::default());
         let lock = Self::acquire_lock(&location)?;
 
         let worktrees = location.join(WORKTREES_DIR);
@@ -98,17 +99,21 @@ impl ProtofetchGitCache {
             "Acquiring a lock on the cache location: {}",
             location.display()
         );
-        match Marker::acquire_to_hold_resource(location, Fail::Immediately, None) {
-            Ok(lock) => Ok(lock),
-            Err(_) => {
-                info!("Failed to acquire a lock on the cache location, retrying");
-                let lock = Marker::acquire_to_hold_resource(
-                    location,
-                    Fail::AfterDurationWithBackoff(Duration::from_secs(300)),
-                    None,
-                )?;
-                info!("Acquired a lock on the cache location");
-                Ok(lock)
+        let start = Instant::now();
+        loop {
+            match Marker::acquire_to_hold_resource(location, Fail::Immediately, None) {
+                Ok(lock) => {
+                    info!("Acquired a lock on the cache location");
+                    return Ok(lock);
+                }
+                Err(error) => {
+                    if start.elapsed() < Duration::from_secs(300) {
+                        debug!("Failed to acquire a lock on the cache location, retrying");
+                        std::thread::sleep(Duration::from_secs(1));
+                    } else {
+                        return Err(error.into());
+                    }
+                }
             }
         }
     }