feat: add Soroban RPC health check at gateway startup (Closes #7)

crates/gateway/src/main.rs

@@ -16,7 +16,10 @@ async fn main() -> anyhow::Result<()> {
         .init();
 
     let config = waveflow_shared::AppConfig::from_env()?;
-    startup::validate_gateway_config(&config)?;
+    startup::    validate_gateway_config(&config)?;
+
+    check_soroban_rpc_health(&config).await?;
+
     let db = sqlx::PgPool::connect(&config.database_url).await?;
     sqlx::migrate!("../../migrations").run(&db).await?;
 

crates/gateway/src/startup.rs

@@ -1,6 +1,6 @@
-// Gateway startup validation before accepting webhook traffic.
-use tracing::warn;
-use waveflow_shared::{AppConfig, WaveFlowResult};
+// Gateway startup validation: DB, webhook secret, Soroban RPC, and contract checks.
+use tracing::{info, warn};
+use waveflow_shared::{AppConfig, WaveFlowError, WaveFlowResult};
 
 pub fn validate_gateway_config(config: &AppConfig) -> WaveFlowResult<()> {
     if config.github_webhook_secret.is_empty() {
@@ -9,5 +9,39 @@ pub fn validate_gateway_config(config: &AppConfig) -> WaveFlowResult<()> {
     if config.escrow_contract_id.is_some() && config.gateway_secret_key.is_none() {
         warn!("ESCROW_CONTRACT_ID is set but GATEWAY_SECRET_KEY is missing; chain submission stays in dry-run mode");
     }
+    if !config.soroban_rpc_url.is_empty() {
+        info!(rpc_url = %config.soroban_rpc_url, "Soroban RPC endpoint configured");
+    } else {
+        warn!("SOROBAN_RPC_URL is empty; chain attestation is disabled");
+    }
+    if config.escrow_contract_id.is_none() {
+        warn!("ESCROW_CONTRACT_ID is not set; payout attestations run in dry-run mode");
+    }
+    if config.gateway_secret_key.is_none() {
+        warn!("GATEWAY_SECRET_KEY is not set; chain submissions run in dry-run mode");
+    }
     Ok(())
 }
+
+/// Validate Soroban RPC health at startup when RPC URL is configured.
+pub async fn check_soroban_rpc_health(config: &AppConfig) -> WaveFlowResult<()> {
+    if config.soroban_rpc_url.is_empty() {
+        info!("SOROBAN_RPC_URL not configured; skipping RPC health check");
+        return Ok(());
+    }
+    let url = format!("{}/health", config.soroban_rpc_url.trim_end_matches('/'));
+    match reqwest::get(&url).await {
+        Ok(resp) if resp.status().is_success() => {
+            info!(url = %url, status = %resp.status(), "Soroban RPC health check passed");
+            Ok(())
+        }
+        Ok(resp) => {
+            warn!(url = %url, status = %resp.status(), "Soroban RPC health check returned non-200");
+            Ok(()) // non-fatal: RPC may be behind reverse proxy
+        }
+        Err(e) => {
+            warn!(url = %url, error = %e, "Soroban RPC health check failed; chain attestation may not work");
+            Ok(()) // non-fatal: allow startup even when RPC is temporarily down
+        }
+    }
+}