Enhance Solana transaction support and add new dependencies

[d4mr]

• Introduced SolanaSigner to the engine core for improved Solana transaction handling.
• Added base64, bincode, solana-client, and solana-sdk as dependencies in Cargo.toml.
• Updated server state to include solana_signer and added new route for signing Solana transactions.

Summary by CodeRabbit

• New Features

  • Added Solana transaction signing API: submit a transaction request and receive a signature plus a base64-encoded signed transaction.
  • Supports execution options (compute unit limits and optional pricing) when preparing transactions.
  • API surfaced in OpenAPI docs and router for straightforward discovery.

• Chores

  • Wired Solana signer and RPC caching into the server so signing requests use cached RPC endpoints.

[coderabbitai]

Walkthrough

Adds Solana transaction signing: new workspace dependencies, a route module implementing signing (builds, signs, serializes transactions), and Solana signer + RPC cache wired into server state and initialization.

Changes

Cohort / File(s)	Summary
Dependency additions server/Cargo.toml	Added workspace dependencies: engine-solana-core (path "../solana-core"), base64, bincode, solana-sdk, solana-client.
Routes module index server/src/http/routes/mod.rs	Declared new public module sign_solana_transaction.
Solana signing route server/src/http/routes/sign_solana_transaction.rs	New Axum route handler sign_solana_transaction with request/response types; resolves RPC client, fetches blockhash, builds versioned transaction, signs via SolanaSigner, serializes signed transaction to base64, returns signature and signed transaction.
Server state & router server/src/http/server.rs	EngineServerState extended with pub solana_signer: Arc<SolanaSigner> and pub solana_rpc_cache: Arc<SolanaRpcCache>; registers the signing route in the v1 router.
Server initialization server/src/main.rs	Initialized SolanaSigner, SolanaRpcUrls, and SolanaRpcCache; wired solana_signer and solana_rpc_cache into EngineServerState; updated EoaSigner construction to clone iaw_client.

Sequence Diagram(s)

sequenceDiagram
    actor Client
    participant Handler as sign_solana_transaction
    participant RpcCache as SolanaRpcCache/RPC
    participant Signer as SolanaSigner

    Client->>Handler: POST /solana/sign/transaction\n(request + credentials)
    Handler->>Handler: Extract chain_id & signer_address\nparse request & exec options
    Handler->>RpcCache: Get RPC client for chain_id
    RpcCache-->>Handler: RPC client
    Handler->>RpcCache: Fetch latest blockhash
    RpcCache-->>Handler: blockhash
    Handler->>Handler: Build versioned transaction\n(set blockhash, compute units/price)
    Handler->>Signer: Sign versioned transaction (credentials)
    Signer-->>Handler: Signed transaction + signature
    Handler->>Handler: Serialize (bincode) -> base64
    Handler-->>Client: 200 OK\n{ signature, signed_transaction }

Loading

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

• Review transaction construction and use of compute unit options in sign_solana_transaction.rs.
• Verify blockhash retrieval/error mapping and serialization (bincode -> base64).
• Check correct initialization and lifetimes of solana_signer, solana_rpc_cache, and cloned iaw_client in main.rs.

Pre-merge checks and finishing touches

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main changes: adding Solana transaction signing capabilities and new dependencies.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch pb/solana-sign-transaction

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

Disabled knowledge base sources:

• Linear integration is disabled by default for public repositories

You can enable these sources in your CodeRabbit configuration.

📥 Commits

Reviewing files that changed from the base of the PR and between a1b60c4 and 92871e4.

⛔ Files ignored due to path filters (1)

• Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (5)

• server/Cargo.toml (2 hunks)
• server/src/http/routes/mod.rs (1 hunks)
• server/src/http/routes/sign_solana_transaction.rs (1 hunks)
• server/src/http/server.rs (3 hunks)
• server/src/main.rs (3 hunks)

🧰 Additional context used

🧬 Code graph analysis (4)

server/src/http/routes/mod.rs (1)

server/src/http/routes/sign_solana_transaction.rs (1)

• sign_solana_transaction (66-144)

server/src/main.rs (3)

server/src/http/server.rs (1)

• new (48-116)

core/src/signer.rs (2)

• new (211-216)
• new (561-566)

server/src/queue/manager.rs (1)

• new (52-318)

server/src/http/routes/sign_solana_transaction.rs (1)

server/src/http/server.rs (1)

• new (48-116)

server/src/http/server.rs (1)

server/src/http/routes/sign_solana_transaction.rs (1)

• sign_solana_transaction (66-144)

[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (2)

server/src/main.rs (2)

63-64: Consider cloning iaw_client on line 64 for consistency.

Line 63 uses iaw_client.clone() for EoaSigner, but line 64 moves iaw_client for SolanaSigner. While moving is more efficient since iaw_client isn't used afterward, using .clone() on both lines would improve consistency with the established pattern (including in queue/manager.rs).

Apply this diff for consistency:

 let eoa_signer = Arc::new(EoaSigner::new(vault_client.clone(), iaw_client.clone()));
-let solana_signer = Arc::new(SolanaSigner::new(vault_client.clone(), iaw_client));
+let solana_signer = Arc::new(SolanaSigner::new(vault_client.clone(), iaw_client.clone()));

---

75-82: Consider consolidating duplicated Solana RPC cache creation.

A separate SolanaRpcCache with identical configuration is also created in queue/manager.rs (lines 66-69 of the relevant snippet). This results in two independent cache instances serving different parts of the system (HTTP routes vs queue workers), which can lead to:

• Wasted memory maintaining duplicate caches
• Configuration drift if URLs are updated in one place but not the other
• Inconsistent cache state

Consider creating the cache once here and passing it as a parameter to QueueManager::new(), similar to how authorization_cache is handled (line 91).

To consolidate, modify QueueManager::new() to accept solana_rpc_cache as a parameter instead of creating it internally:

 let queue_manager = QueueManager::new(
     redis_client.clone(),
     &config.queue,
     &config.solana,
     chains.clone(),
     signer.clone(),
     eoa_signer.clone(),
     authorization_cache.clone(),
     kms_client_cache.clone(),
+    solana_rpc_cache.clone(),
 )
 .await?;

Then update the QueueManager::new signature in queue/manager.rs to accept the cache instead of creating it.

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

Disabled knowledge base sources:

• Linear integration is disabled by default for public repositories

You can enable these sources in your CodeRabbit configuration.

📥 Commits

Reviewing files that changed from the base of the PR and between 92871e4 and fb90893.

📒 Files selected for processing (3)

• server/src/http/routes/sign_solana_transaction.rs (1 hunks)
• server/src/http/server.rs (3 hunks)
• server/src/main.rs (4 hunks)

🚧 Files skipped from review as they are similar to previous changes (2)

• server/src/http/server.rs
• server/src/http/routes/sign_solana_transaction.rs

🧰 Additional context used

🧬 Code graph analysis (1)

server/src/main.rs (3)

server/src/http/server.rs (1)

• new (50-118)

core/src/signer.rs (2)

• new (211-216)
• new (561-566)

server/src/queue/manager.rs (1)

• new (52-318)

🔇 Additional comments (2)

server/src/main.rs (2)

3-4: LGTM!

The new imports for Solana support are appropriate and all are used in the initialization flow.

---

137-138: LGTM!

The solana_signer and solana_rpc_cache are correctly added to EngineServerState following the established pattern for shared resources, with appropriate Arc cloning for thread-safe access.