Update price feeds if header changed by validator

- currently not validating price feeds if the underlying header already exists
  and is valid, since price feeds should have been added when initial header
  was added

pkg/datastore/postgres/repositories/header_repository.go

@@ -2,10 +2,13 @@ package repositories
 
 import (
 	"database/sql"
+	"errors"
 	"github.com/vulcanize/vulcanizedb/pkg/core"
 	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
 )
 
+var ErrValidHeaderExists = errors.New("valid header already exists")
+
 type HeaderRepository struct {
 	database *postgres.DB
 }
@@ -25,7 +28,7 @@ func (repository HeaderRepository) CreateOrUpdateHeader(header core.Header) (int
 	if headerMustBeReplaced(hash, header) {
 		return repository.replaceHeader(header)
 	}
-	return 0, err
+	return 0, ErrValidHeaderExists
 }
 
 func (repository HeaderRepository) GetHeader(blockNumber int64) (core.Header, error) {

pkg/datastore/postgres/repositories/header_repository_test.go

@@ -13,7 +13,6 @@ import (
 
 var _ = Describe("Block header repository", func() {
 	Describe("creating or updating a header", func() {
-
 		It("adds a header", func() {
 			node := core.Node{}
 			db := test_config.NewTestDB(node)
@@ -56,7 +55,7 @@ var _ = Describe("Block header repository", func() {
 			Expect(ethNodeFingerprint).To(Equal(db.Node.ID))
 		})
 
-		It("does not duplicate headers", func() {
+		It("returns valid header exists error if attempting duplicate headers", func() {
 			node := core.Node{}
 			db := test_config.NewTestDB(node)
 			test_config.CleanTestDB(db)
@@ -71,7 +70,8 @@ var _ = Describe("Block header repository", func() {
 			Expect(err).NotTo(HaveOccurred())
 
 			_, err = repo.CreateOrUpdateHeader(header)
-			Expect(err).NotTo(HaveOccurred())
+			Expect(err).To(HaveOccurred())
+			Expect(err).To(MatchError(repositories.ErrValidHeaderExists))
 
 			var dbHeaders []core.Header
 			err = db.Select(&dbHeaders, `SELECT block_number, hash, raw FROM public.headers WHERE block_number = $1`, header.BlockNumber)