From 7a8f0135b35ca43a58483873527bc992b8fcc740 Mon Sep 17 00:00:00 2001
From: Matthew Jaffee <jaffee@pilosa.com>
Date: Mon, 6 Dec 2021 10:36:55 -0600
Subject: [PATCH] redirect GetTranslateData if node doesn't own partition

---
 api.go          | 18 ++++++++++++++++++
 http/handler.go |  6 ++++++
 2 files changed, 24 insertions(+)

diff --git a/api.go b/api.go
index 07e971599..6fd8d38cc 100644
--- a/api.go
+++ b/api.go
@@ -834,6 +834,15 @@ func (api *API) FragmentData(ctx context.Context, indexName, fieldName, viewName
 	return f, nil
 }
 
+type RedirectError struct {
+	HostPort string
+	error    string
+}
+
+func (r RedirectError) Error() string {
+	return r.error
+}
+
 // TranslateData returns all translation data in the specified partition.
 func (api *API) TranslateData(ctx context.Context, indexName string, partition int) (io.WriterTo, error) {
 	span, _ := tracing.StartSpanFromContext(ctx, "API.TranslateData")
@@ -849,6 +858,15 @@ func (api *API) TranslateData(ctx context.Context, indexName string, partition i
 		return nil, newNotFoundError(ErrIndexNotFound, indexName)
 	}
 
+	snap := topology.NewClusterSnapshot(api.cluster.noder, api.cluster.Hasher, api.cluster.ReplicaN)
+	nodes := snap.PartitionNodes(partition)
+	if nodes[0].ID != api.server.NodeID() {
+		return nil, RedirectError{
+			HostPort: nodes[0].URI.HostPort(),
+			error:    fmt.Sprintf("can't translate data, this node(%s) does not partition %d", api.server.uri, partition),
+		}
+	}
+
 	// Retrieve translatestore from holder.
 	store := idx.TranslateStore(partition)
 	if store == nil {
diff --git a/http/handler.go b/http/handler.go
index 94665bbfa..9e626babf 100644
--- a/http/handler.go
+++ b/http/handler.go
@@ -2326,6 +2326,12 @@ func (h *Handler) handleGetTranslateData(w http.ResponseWriter, r *http.Request)
 
 	// Retrieve partition data from holder.
 	p, err := h.api.TranslateData(r.Context(), q.Get("index"), int(partition))
+	if redir, ok := err.(pilosa.RedirectError); ok {
+		newURL := *r.URL
+		newURL.Host = redir.HostPort
+		http.Redirect(w, r, newURL.String(), http.StatusSeeOther)
+		return
+	}
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusNotFound)
 		return