refactor(coprocessor): use shared locked solc install util

Author: Eikix

coprocessor/fhevm-engine/Cargo.lock

@@ -1,6 +1,7 @@
 [workspace]
 resolver = "2"
 members = [
+    "solc-build-utils",
     "tfhe-worker",
     "fhevm-engine-common",
     "host-listener",
@@ -46,6 +47,7 @@ clap = { version = "4.5.38", features = ["derive", "env"] }
 daggy = "0.8.1"
 foundry-compilers = { version = "0.19.1", features = ["svm-solc"] }
 futures-util = "0.3.31"
+fs4 = "0.13.1"
 hex = "0.4.3"
 lru = "0.13.0"
 opentelemetry = "0.29.1"

coprocessor/fhevm-engine/Cargo.toml

@@ -41,6 +41,7 @@ fhevm_gateway_bindings = { path = "../../../gateway-contracts/rust_bindings" }
 [build-dependencies]
 foundry-compilers = { workspace = true }
 semver = { workspace = true }
+solc-build-utils = { path = "../solc-build-utils" }
 
 [dev-dependencies]
 alloy = { workspace = true, features = ["node-bindings"] }

coprocessor/fhevm-engine/build-utils/solc_retry.rs

@@ -2,14 +2,12 @@ use std::{env, path::Path};
 
 use foundry_compilers::{multi::MultiCompiler, solc::SolcCompiler, Project, ProjectPathsConfig};
 use semver::Version;
-
-#[path = "../build-utils/solc_retry.rs"]
-mod solc_retry;
+use solc_build_utils::find_or_install_solc_locked;
 
 fn main() {
     let paths = ProjectPathsConfig::hardhat(Path::new(env!("CARGO_MANIFEST_DIR"))).unwrap();
     // Use a specific version due to an issue with libc and libstdc++ in the rust Docker image we use to run it.
-    let solc = solc_retry::find_or_install_solc(&Version::new(0, 8, 28));
+    let solc = find_or_install_solc_locked(&Version::new(0, 8, 28));
     let project = Project::builder()
         .paths(paths)
         .build(MultiCompiler::new(Some(SolcCompiler::Specific(solc)), None).unwrap())

coprocessor/fhevm-engine/gw-listener/Cargo.toml

@@ -51,3 +51,4 @@ tracing-test = { workspace = true }
 foundry-compilers = { workspace = true }
 foundry-compilers-artifacts = "0.13"
 semver = { workspace = true }
+solc-build-utils = { path = "../solc-build-utils" }

coprocessor/fhevm-engine/gw-listener/build.rs

@@ -2,11 +2,9 @@ use foundry_compilers::{
     multi::MultiCompiler, solc::SolcCompiler, Project, ProjectPathsConfig,
 };
 use semver::Version;
+use solc_build_utils::find_or_install_solc_locked;
 use std::{env, fs, path::Path, process::Command};
 
-#[path = "../build-utils/solc_retry.rs"]
-mod solc_retry;
-
 fn build_contracts() {
     println!(
         "cargo:rerun-if-changed=../../../host-contracts/contracts/ACL.sol"
@@ -83,7 +81,7 @@ fn main() {
             .unwrap();
     // Use a specific version due to an issue with libc and libstdc++ in the
     // rust Docker image we use to run it.
-    let solc = solc_retry::find_or_install_solc(&Version::new(0, 8, 28));
+    let solc = find_or_install_solc_locked(&Version::new(0, 8, 28));
     let project = Project::builder()
         .paths(paths)
         .build(

coprocessor/fhevm-engine/host-listener/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "solc-build-utils"
+version = "0.1.0"
+edition.workspace = true
+license.workspace = true
+
+[lib]
+path = "src/lib.rs"
+
+[dependencies]
+foundry-compilers = { workspace = true }
+fs4 = { workspace = true }
+semver = { workspace = true }

coprocessor/fhevm-engine/host-listener/build.rs

@@ -0,0 +1,32 @@
+use foundry_compilers::solc::Solc;
+use fs4::fs_std::FileExt;
+use semver::Version;
+use std::fs::OpenOptions;
+
+const SOLC_INSTALL_LOCK_FILE: &str = "fhevm-solc-install.lock";
+
+pub fn find_or_install_solc_locked(version: &Version) -> Solc {
+    let lock_path = std::env::temp_dir().join(SOLC_INSTALL_LOCK_FILE);
+    let lock_file = OpenOptions::new()
+        .read(true)
+        .write(true)
+        .create(true)
+        .truncate(false)
+        .open(&lock_path)
+        .unwrap_or_else(|err| {
+            panic!(
+                "Failed to open solc install lock file {}: {err}",
+                lock_path.display()
+            );
+        });
+
+    lock_file.lock_exclusive().unwrap_or_else(|err| {
+        panic!(
+            "Failed to acquire solc install lock {}: {err}",
+            lock_path.display()
+        );
+    });
+
+    Solc::find_or_install(version)
+        .unwrap_or_else(|err| panic!("Failed to find or install solc {version}: {err:?}"))
+}

coprocessor/fhevm-engine/solc-build-utils/Cargo.toml

@@ -39,6 +39,7 @@ fhevm_gateway_bindings = { path = "../../../gateway-contracts/rust_bindings" }
 [build-dependencies]
 foundry-compilers = { workspace = true }
 semver = { workspace = true }
+solc-build-utils = { path = "../solc-build-utils" }
 
 [dev-dependencies]
 alloy = { workspace = true, features = ["node-bindings"] }