style: define is503 function to follow isABC pattern

server/errors.go

@@ -6,6 +6,7 @@ import (
 
 	"github.com/Layr-Labs/eigenda-proxy/commitments"
 	"github.com/Layr-Labs/eigenda-proxy/common"
+	"github.com/Layr-Labs/eigenda/api"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
 )
@@ -44,3 +45,9 @@ func is429(err error) bool {
 	st, isGRPCError := status.FromError(err)
 	return isGRPCError && st.Code() == codes.ResourceExhausted
 }
+
+// 503 is returned to tell the caller (batcher) to failover to ethda b/c eigenda is temporarily down
+func is503(err error) bool {
+	// TODO: would be cleaner to define a sentinel error in eigenda-core and use that instead
+	return errors.Is(err, &api.ErrorFailover{})
+}

server/handlers.go

@@ -9,7 +9,6 @@ import (
 	"net/http"
 
 	"github.com/Layr-Labs/eigenda-proxy/commitments"
-	"github.com/Layr-Labs/eigenda/api"
 	"github.com/gorilla/mux"
 )
 
@@ -186,7 +185,7 @@ func (svr *Server) handlePostShared(w http.ResponseWriter, r *http.Request, comm
 			http.Error(w, err.Error(), http.StatusBadRequest)
 		case is429(err):
 			http.Error(w, err.Error(), http.StatusTooManyRequests)
-		case errors.Is(err, &api.ErrorFailover{}):
+		case is503(err):
 			// this tells the caller (batcher) to failover to ethda b/c eigenda is temporarily down
 			http.Error(w, err.Error(), http.StatusServiceUnavailable)
 		default: