Fix CI - Attempt #2

.github/workflows/build_and_test.yaml

@@ -43,9 +43,7 @@ jobs:
         # Otherwise only the last build to finish would get saved to the cache.
         # We allow different test_flags to share a cache as they should have identical build outputs
         key: ${{ matrix.runner }} - ${{ matrix.cargo_flags }}
-        cache-directories: |
-          target/debug/jassets
-          target/release/jassets
+        cache-directories: "test-helpers/j4rs"
 
         # this line means that only the main branch writes to the cache
         # benefits:

.gitignore

@@ -12,4 +12,5 @@
 /docs/mdbook_bin
 /shotover-proxy/build/packages
 /some_local_file
-/test-helpers/src/connection/kafka/node/node_modules
+/test-helpers/src/connection/kafka/node/node_modules
+/test-helpers/j4rs

test-helpers/Cargo.toml

@@ -42,3 +42,6 @@ rustls-pemfile = "2.0.0"
 tokio-tungstenite = { version = "0.24", features = ["rustls-tls-native-roots"] }
 pretty_assertions.workspace = true
 serde.workspace = true
+
+[build-dependencies]
+j4rs = "0.21.0"

test-helpers/build.rs

@@ -0,0 +1,20 @@
+use j4rs::errors::J4RsError;
+
+fn main() {
+    println!("cargo:rerun-if-changed=build.rs");
+
+    std::fs::create_dir("j4rs").ok();
+    match j4rs::Jvm::copy_j4rs_libs_under("j4rs") {
+        Ok(()) => {}
+        Err(J4RsError::GeneralError(e)) => {
+            // if the jassets directory has been deleted (maybe it wasnt cached with the rest of the build)
+            // then we may still have a functioning j4rs directory from a previous run
+            if e != "Can not find jassets directory" {
+                panic!("j4rs lib copy failed with: GeneralError({e})")
+            }
+        }
+        Err(e) => {
+            panic!("j4rs lib copy failed with: {e}")
+        }
+    }
+}

test-helpers/src/connection/java.rs

@@ -11,7 +11,12 @@ impl Jvm {
     /// Construct a JVM, downloads the list of deps from the maven repository.
     /// Example dep string: "org.slf4j:slf4j-api:1.7.36"
     pub(crate) fn new(deps: &[&str]) -> Self {
-        let jvm = Rc::new(JvmBuilder::new().build().unwrap());
+        let jvm = Rc::new(
+            JvmBuilder::new()
+                .with_base_path("../test-helpers/j4rs")
+                .build()
+                .unwrap(),
+        );
 
         for dep in deps {
             jvm.deploy_artifact(&MavenArtifact::from(*dep)).unwrap();