From 4360c024b655b275497ea2dd33bc26b7ac745878 Mon Sep 17 00:00:00 2001
From: Bo Du <bo@chronosphere.io>
Date: Fri, 25 Oct 2019 16:32:50 -0400
Subject: [PATCH] Custom error type/check.

---
 src/dbnode/namespace/schema_registry.go         | 14 +++++++++++++-
 src/dbnode/namespace/schema_registry_updater.go | 11 ++++++-----
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/src/dbnode/namespace/schema_registry.go b/src/dbnode/namespace/schema_registry.go
index bfc11ea03f..014f19d4d2 100644
--- a/src/dbnode/namespace/schema_registry.go
+++ b/src/dbnode/namespace/schema_registry.go
@@ -31,6 +31,18 @@ import (
 	"go.uber.org/zap"
 )
 
+func newSchemaHistoryNotFoundError(nsIDStr string) error {
+	return &schemaHistoryNotFoundError{nsIDStr}
+}
+
+type schemaHistoryNotFoundError struct {
+	nsIDStr string
+}
+
+func (s *schemaHistoryNotFoundError) Error() string {
+	return fmt.Sprintf("schema history is not found for %s", s.nsIDStr)
+}
+
 type schemaRegistry struct {
 	sync.RWMutex
 
@@ -125,7 +137,7 @@ func (sr *schemaRegistry) getSchemaHistory(nsIDStr string) (SchemaHistory, error
 
 	history, ok := sr.registry[nsIDStr]
 	if !ok {
-		return nil, fmt.Errorf("schema history is not found for %v", nsIDStr)
+		return nil, newSchemaHistoryNotFoundError(nsIDStr)
 	}
 	return history.Get().(SchemaHistory), nil
 }
diff --git a/src/dbnode/namespace/schema_registry_updater.go b/src/dbnode/namespace/schema_registry_updater.go
index 472da93c96..245103ca1a 100644
--- a/src/dbnode/namespace/schema_registry_updater.go
+++ b/src/dbnode/namespace/schema_registry_updater.go
@@ -22,7 +22,6 @@ package namespace
 
 import (
 	"fmt"
-	"strings"
 
 	xerrors "github.com/m3db/m3/src/x/errors"
 
@@ -39,10 +38,12 @@ func UpdateSchemaRegistry(newNamespaces Map, schemaReg SchemaRegistry, log *zap.
 			curSchemaNone = true
 		)
 		curSchema, err := schemaReg.GetLatestSchema(metadata.ID())
-		// NB(bodu): Schema history not found is a valid error as this occurs on initial bootstrap for the db.
-		if err != nil && !strings.Contains(err.Error(), "schema history is not found for") {
-			multiErr = multiErr.Add(fmt.Errorf("cannot get latest namespace schema: %v", err))
-			continue
+		if err != nil {
+			// NB(bodu): Schema history not found is a valid error as this occurs on initial bootstrap for the db.
+			if _, ok := err.(*schemaHistoryNotFoundError); !ok {
+				multiErr = multiErr.Add(fmt.Errorf("cannot get latest namespace schema: %v", err))
+				continue
+			}
 		}
 
 		if curSchema != nil {