generalize new fields introduced in higher versions.

Signed-off-by: Siyuan Zhang <sizhang@google.com>

server/storage/schema/changes.go

@@ -21,17 +21,22 @@ type schemaChange interface {
 	downgradeAction() action
 }
 
-// addNewField represents adding new field when upgrading. Downgrade will remove the field.
-func addNewField(bucket backend.Bucket, fieldName []byte, fieldValue []byte) schemaChange {
+type NewField struct {
+	Bucket     backend.Bucket
+	FieldName  []byte
+	FieldValue []byte
+}
+
+func (f *NewField) schemaChange() schemaChange {
 	return simpleSchemaChange{
 		upgrade: setKeyAction{
-			Bucket:     bucket,
-			FieldName:  fieldName,
-			FieldValue: fieldValue,
+			Bucket:     f.Bucket,
+			FieldName:  f.FieldName,
+			FieldValue: f.FieldValue,
 		},
 		downgrade: deleteKeyAction{
-			Bucket:    bucket,
-			FieldName: fieldName,
+			Bucket:    f.Bucket,
+			FieldName: f.FieldName,
 		},
 	}
 }

server/storage/schema/changes_test.go

@@ -30,7 +30,7 @@ func TestUpgradeDowngrade(t *testing.T) {
 	}{
 		{
 			name:                    "addNewField empty",
-			change:                  addNewField(Meta, []byte("/test"), []byte("1")),
+			change:                  (&NewField{Meta, []byte("/test"), []byte("1")}).schemaChange(),
 			expectStateAfterUpgrade: map[string]string{"/test": "1"},
 		},
 	}

server/storage/schema/schema.go

@@ -123,14 +123,37 @@ func schemaChangesForVersion(v semver.Version, isUpgrade bool) ([]schemaChange,
 	return actions, nil
 }
 
+func NewFieldsForVersion(v semver.Version) []NewField {
+	if newFields, found := newFieldsMapping[v]; found {
+		return newFields
+	}
+	return nil
+}
+
+func newFieldMappingsToSchemaChanges(newFieldMap map[semver.Version][]NewField) map[semver.Version][]schemaChange {
+	schemaChangeMap := map[semver.Version][]schemaChange{}
+	for ver, newFields := range newFieldMap {
+		changes := []schemaChange{}
+		for _, f := range newFields {
+			changes = append(changes, f.schemaChange())
+		}
+		schemaChangeMap[ver] = changes
+	}
+	return schemaChangeMap
+}
+
 var (
-	// schemaChanges list changes that were introduced in a particular version.
+	// newFieldsMapping list new fields that were introduced in a particular version.
 	// schema was introduced in v3.6 as so its changes were not tracked before.
-	schemaChanges = map[semver.Version][]schemaChange{
+	newFieldsMapping = map[semver.Version][]NewField{
 		version.V3_6: {
-			addNewField(Meta, MetaStorageVersionName, emptyStorageVersion),
+			{Meta, MetaStorageVersionName, emptyStorageVersion},
 		},
 	}
+	// schemaChanges list changes that were introduced in a particular version.
+	// schema was introduced in v3.6 as so its changes were not tracked before.
+	schemaChanges = newFieldMappingsToSchemaChanges(newFieldsMapping)
+
 	// emptyStorageVersion is used for v3.6 Step for the first time, in all other version StoragetVersion should be set by migrator.
 	// Adding a addNewField for StorageVersion we can reuse logic to remove it when downgrading to v3.5
 	emptyStorageVersion = []byte("")

tests/framework/e2e/etcd_process.go

@@ -31,7 +31,6 @@ import (
 	"github.com/coreos/go-semver/semver"
 	"go.uber.org/zap"
 
-	"go.etcd.io/etcd/api/v3/version"
 	"go.etcd.io/etcd/client/pkg/v3/fileutil"
 	"go.etcd.io/etcd/pkg/v3/expect"
 	"go.etcd.io/etcd/pkg/v3/proxy"
@@ -279,12 +278,17 @@ func (ep *EtcdServerProcess) VerifySchemaVersion(lg *zap.Logger) error {
 	if currentEtcdVer.LessThan(ver) || ver.LessThan(prevEtcdVer) {
 		return fmt.Errorf("expect backend schema version to be between [%s, %s], but got %s", prevEtcdVer.String(), currentEtcdVer.String(), ver.String())
 	}
-	// check new fields introduced in V3_6 do not exist in V3_5 data file.
-	// V3_6 contains all the fields in V3_5, so no need to check for V3_6 servers.
-	if *currentEtcdVer == version.V3_5 {
-		_, vs := be.BatchTx().UnsafeRange(schema.Meta, schema.MetaStorageVersionName, nil, 1)
+	// storage schema is generally backward compatible. No need to check the buckets for higher version.
+	if ep.cfg.ExecPath == BinPath.Etcd {
+		return nil
+	}
+	lg.Info("verify no new storage schema field is present in the db file of last release process")
+	nextEtcdVer := semver.Version{Major: currentEtcdVer.Major, Minor: currentEtcdVer.Minor + 1}
+	newFields := schema.NewFieldsForVersion(nextEtcdVer)
+	for _, f := range newFields {
+		_, vs := be.BatchTx().UnsafeRange(f.Bucket, f.FieldName, nil, 1)
 		if len(vs) != 0 {
-			return fmt.Errorf("expect storageVersion not exist in the meta bucket, but got %s", string(vs[0]))
+			return fmt.Errorf("expect %s not exist in the %s bucket, but got %s", f.Bucket.Name(), f.FieldName, vs[0])
 		}
 	}
 	return nil