Add more detail for 404s

validator_client/src/http_api/create_signed_voluntary_exit.rs

@@ -20,11 +20,20 @@ pub async fn create_signed_voluntary_exit<T: 'static + SlotClock + Clone, E: Eth
     };
 
     let pubkey_bytes = PublicKeyBytes::from(pubkey);
+    if !validator_store.has_validator(&pubkey_bytes) {
+        return Err(warp_utils::reject::custom_not_found(format!(
+            "{} is disabled or not mangaged by this validator client",
+            pubkey_bytes.as_hex_string()
+        )));
+    }
+
     let validator_index = validator_store
         .validator_index(&pubkey_bytes)
         .ok_or_else(|| {
             warp_utils::reject::custom_not_found(format!(
-                "Unable to find validator with public key: {}",
+                "The validator index for {} is not known. The validator client \
+                may still be initializing or the validator has not yet had a \
+                deposit processed.",
                 pubkey_bytes.as_hex_string()
             ))
         })?;

validator_client/src/validator_store.rs

@@ -156,6 +156,14 @@ impl<T: SlotClock + 'static, E: EthSpec> ValidatorStore<T, E> {
         self.validators.clone()
     }
 
+    /// Indicates if the `voting_public_key` exists in self and is enabled.
+    pub fn has_validator(&self, voting_public_key: &PublicKeyBytes) -> bool {
+        self.validators
+            .read()
+            .validator(voting_public_key)
+            .is_some()
+    }
+
     /// Insert a new validator to `self`, where the validator is represented by an EIP-2335
     /// keystore on the filesystem.
     #[allow(clippy::too_many_arguments)]