Reject invalid deployment configuration early

crates/remora-worker/src/application.rs

@@ -61,7 +61,7 @@ impl WorkerApplicationConfig {
                 endpoint: target.endpoint.clone(),
                 region: target.region.clone(),
             });
-        Ok(Self {
+        let config = Self {
             management: ManagementConfig::from_env(crate::COMPONENT_NAME)?,
             database_url: required_env("DATABASE_URL")?,
             database_connections: env_parse("REMORA_DATABASE_MAX_CONNECTIONS", "16")?,
@@ -124,7 +124,9 @@ impl WorkerApplicationConfig {
                 "REMORA_HUGGING_FACE_ENDPOINT",
                 "https://huggingface.co",
             ),
-        })
+        };
+        validate_worker_timing(&config.coordination, &config.worker)?;
+        Ok(config)
     }
 }
 
@@ -324,6 +326,27 @@ fn parse_scheme_ports(input: &str) -> Result<Vec<(String, u16)>, RuntimeError> {
         .collect()
 }
 
+fn validate_worker_timing(
+    coordination: &StoreConfig,
+    worker: &WorkerConfig,
+) -> Result<(), RuntimeError> {
+    if coordination.global_limit == 0
+        || coordination.lease_ttl.is_zero()
+        || coordination.reserve_ttl.is_zero()
+        || coordination.progress_ttl.is_zero()
+        || worker.local_limit == 0
+        || worker.idle_delay.is_zero()
+        || worker.renew_interval.is_zero()
+        || worker.renew_interval >= coordination.lease_ttl
+        || worker.cancel_poll_interval.is_zero()
+    {
+        return Err(RuntimeError::message(
+            "worker limits and timing must be positive, and renewal must precede lease expiry",
+        ));
+    }
+    Ok(())
+}
+
 async fn wait_for_shutdown() -> Result<(), RuntimeError> {
     #[cfg(unix)]
     {
@@ -387,4 +410,19 @@ mod tests {
         assert!(parse_scheme_ports("https").is_err());
         assert!(parse_cidrs("private").is_err());
     }
+
+    #[test]
+    fn validates_worker_timing_before_external_connections() {
+        let coordination = StoreConfig {
+            global_limit: 1,
+            lease_ttl: Duration::from_secs(30),
+            reserve_ttl: Duration::from_secs(30),
+            progress_ttl: Duration::from_secs(60),
+            cancel_ttl: None,
+        };
+        let mut worker = WorkerConfig::default();
+        assert!(validate_worker_timing(&coordination, &worker).is_ok());
+        worker.renew_interval = coordination.lease_ttl;
+        assert!(validate_worker_timing(&coordination, &worker).is_err());
+    }
 }