ent · a8m · Aug 24, 2021 · Aug 23, 2021 · Aug 23, 2021 · Aug 24, 2021
diff --git a/doc/md/schema-fields.md b/doc/md/schema-fields.md
@@ -401,6 +401,7 @@ The framework provides a few built-in validators for each type:
 
 - `[]byte`
   - `MaxLen(i)`
+  - `MinLen(i)`
 
 ## Optional
 

diff --git a/entc/integration/ent/runtime.go b/entc/integration/ent/runtime.go
diff --git a/entc/integration/ent/schema/fieldtype.go b/entc/integration/ent/schema/fieldtype.go
@@ -197,7 +197,8 @@ func (FieldType) Fields() []ent.Field { //nolint:funlen
 			GoType(&sql.NullTime{}),
 		field.Bytes("raw_data").
 			Optional().
-			MaxLen(20),
+			MaxLen(20).
+			MinLen(3),
 		field.Bytes("ip").
 			Optional().
 			GoType(net.IP("127.0.0.1")).

diff --git a/entc/integration/gremlin/ent/runtime.go b/entc/integration/gremlin/ent/runtime.go
diff --git a/entc/integration/type_test.go b/entc/integration/type_test.go
@@ -125,8 +125,16 @@ func Types(t *testing.T, client *ent.Client) {
 		SetInt64(64).
 		SetRawData(make([]byte, 40)).
 		Save(ctx)
-	require.Error(err)
-
+	require.Error(err, "MaxLen validator should reject this operation")
+	_, err = client.FieldType.Create().
+		SetInt(1).
+		SetInt8(8).
+		SetInt16(16).
+		SetInt32(32).
+		SetInt64(64).
+		SetRawData(make([]byte, 2)).
+		Save(ctx)
+	require.Error(err, "MinLen validator should reject this operation")
 	ft = ft.Update().
 		SetInt(1).
 		SetInt8(math.MaxInt8).

diff --git a/schema/field/field.go b/schema/field/field.go
@@ -588,6 +588,18 @@ func (b *bytesBuilder) MaxLen(i int) *bytesBuilder {
 	return b
 }
 
+// MinLen adds a length validator for this field.
+// Operation fails if the length of the buffer is less than the given value.
+func (b *bytesBuilder) MinLen(i int) *bytesBuilder {
+	b.desc.Validators = append(b.desc.Validators, func(b []byte) error {
+		if len(b) < i {
+			return errors.New("value is less than the required length")
+		}
+		return nil
+	})
+	return b
+}
+
 // Validate adds a validator for this field. Operation fails if the validation fails.
 //
 //	field.Bytes("blob").