feat: finish relay server implementation

Cargo.toml

@@ -89,6 +89,8 @@ testcontainers = "0.26"
 test-case = "3.3"
 tree_hash = "0.12"
 tree_hash_derive = "0.12"
+tar = "0.4"
+flate2 = "1.1"
 wiremock = "0.6"
 
 # Crates in the workspace

crates/app/Cargo.toml

@@ -28,6 +28,9 @@ serde_json.workspace = true
 hex.workspace = true
 k256.workspace = true
 bon.workspace = true
+flate2.workspace = true
+tar.workspace = true
+tempfile.workspace = true
 pluto-cluster.workspace = true
 pluto-k1util.workspace = true
 pluto-crypto.workspace = true
@@ -36,8 +39,8 @@ pluto-crypto.workspace = true
 pluto-build-proto.workspace = true
 
 [dev-dependencies]
-tempfile.workspace = true
 wiremock.workspace = true
+test-case.workspace = true
 
 [lints]
 workspace = true

crates/app/src/lib.rs

@@ -27,3 +27,6 @@ pub mod eth2wrap;
 
 /// Private key locking service.
 pub mod privkeylock;
+
+/// Utility helpers for archiving, extracting, and comparing files/directories.
+pub mod utils;

crates/app/src/obolapi/error.rs

@@ -59,6 +59,14 @@ pub enum Error {
     #[error("signature string has invalid size: {0}")]
     InvalidSignatureSize(usize),
 
+    /// Failed to convert share index to u8.
+    #[error("failed to convert share index to u8: {0}")]
+    FailedToConvertShareIndexToU8(#[from] std::num::TryFromIntError),
+
+    /// Math overflow error.
+    #[error("math overflow error")]
+    MathOverflow,
+
     /// Epoch parsing error.
     #[error("epoch parsing error: {0}")]
     EpochParse(#[from] std::num::ParseIntError),

crates/app/src/obolapi/exit.rs

@@ -346,9 +346,12 @@ impl Client {
             let mut sig = [0u8; 96];
             sig.copy_from_slice(&sig_bytes);
 
-            // `BlstImpl::threshold_aggregate` shifts the index to 1-based internally
+            // Convert 0-indexed array position to 1-indexed share ID (API stores signatures
+            // at array position share_id-1, e.g., share 1 at position 0)
             let share_idx = u8::try_from(sig_idx)
-                .map_err(|_| Error::InvalidSignatureSize(sig_idx.saturating_add(1)))?;
+                .map_err(Error::FailedToConvertShareIndexToU8)?
+                .checked_add(1)
+                .ok_or(Error::MathOverflow)?;
             raw_signatures.insert(share_idx, sig);
         }