Add migration and new schema version for resource_string

random/resource_string.go

@@ -11,10 +11,11 @@ import (
 
 func resourceString() *schema.Resource {
 	return &schema.Resource{
-		Create: CreateString,
-		Read:   ReadString,
-		Delete: schema.RemoveFromState,
-
+		Create:        CreateString,
+		Read:          ReadString,
+		Delete:        schema.RemoveFromState,
+		MigrateState:  resourceRandomStringMigrateState,
+		SchemaVersion: 1,
 		Schema: map[string]*schema.Schema{
 			"keepers": {
 				Type:     schema.TypeMap,

random/resource_string_migration.go

@@ -0,0 +1,50 @@
+package random
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func resourceRandomStringMigrateState(
+	v int, is *terraform.InstanceState, meta interface{}) (*terraform.InstanceState, error) {
+	switch v {
+	case 0:
+		log.Println("[INFO] Found random string state v0; migrating to v1")
+		return migrateStringStateV0toV1(is)
+	default:
+		return is, fmt.Errorf("Unexpected schema version: %d", v)
+	}
+}
+
+func redactAttributes(is *terraform.InstanceState) map[string]string {
+	redactedAttributes := make(map[string]string)
+	for k, v := range is.Attributes {
+		redactedAttributes[k] = v
+		if k == "id" || k == "result" {
+			redactedAttributes[k] = "<sensitive>"
+		}
+	}
+	return redactedAttributes
+}
+
+func migrateStringStateV0toV1(is *terraform.InstanceState) (*terraform.InstanceState, error) {
+	if is.Empty() {
+		log.Println("[DEBUG] Empty InstanceState; nothing to migrate.")
+		return is, nil
+	}
+
+	log.Printf("[DEBUG] Random String Attributes before Migration: %#v", redactAttributes(is))
+
+	keys := []string{"min_numeric", "min_upper", "min_lower", "min_special"}
+	for _, k := range keys {
+		if v := is.Attributes[k]; v == "" {
+			is.Attributes[k] = "0"
+		}
+	}
+
+	log.Printf("[DEBUG] Random String Attributes after State Migration: %#v", redactAttributes(is))
+
+	return is, nil
+}

random/resource_string_migration_test.go

@@ -0,0 +1,77 @@
+package random
+
+import (
+	"testing"
+
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func TestResourceStringMigrateState(t *testing.T) {
+	cases := map[string]struct {
+		StateVersion       int
+		ID                 string
+		InputAttributes    map[string]string
+		ExpectedAttributes map[string]string
+		Meta               interface{}
+	}{
+		"v0_1_simple": {
+			StateVersion: 0,
+			ID:           "some_id",
+			InputAttributes: map[string]string{
+				"result": "foo",
+				"id":     "foo",
+				"length": "3",
+			},
+			ExpectedAttributes: map[string]string{
+				"result":      "foo",
+				"id":          "foo",
+				"length":      "3",
+				"min_numeric": "0",
+				"min_special": "0",
+				"min_lower":   "0",
+				"min_upper":   "0",
+			},
+		},
+		"v0_1_special": {
+			StateVersion: 0,
+			ID:           "some_id",
+			InputAttributes: map[string]string{
+				"result":           "foo",
+				"id":               "foo",
+				"special":          "false",
+				"length":           "3",
+				"override_special": "!@",
+			},
+			ExpectedAttributes: map[string]string{
+				"result":           "foo",
+				"id":               "foo",
+				"special":          "false",
+				"length":           "3",
+				"override_special": "!@",
+				"min_numeric":      "0",
+				"min_special":      "0",
+				"min_lower":        "0",
+				"min_upper":        "0",
+			},
+		},
+	}
+
+	for tn, tc := range cases {
+		is := &terraform.InstanceState{
+			ID:         tc.ID,
+			Attributes: tc.InputAttributes,
+		}
+		is, err := resourceRandomStringMigrateState(tc.StateVersion, is, tc.Meta)
+
+		if err != nil {
+			t.Fatalf("bad: %s, err: %#v", tn, err)
+		}
+
+		for k, v := range tc.ExpectedAttributes {
+			actual := is.Attributes[k]
+			if actual != v {
+				t.Fatalf("Bad Random String Migration for %q: %q\n\n expected: %q", k, actual, v)
+			}
+		}
+	}
+}