Migrate opentsdb string fields to int (#401)

This fixes a migration bug introduced by #398
We unfortunately have to add a schema migration function to convert the strings to int
Since 1.20.0 is released, we cannot just go back to a string at this point, so a migration is the way forward

Fixes #400
We should release 1.20.1 once that's merged

grafana/resource_data_source.go

@@ -26,10 +26,12 @@ The required arguments for this resource vary depending on the type of data
 source selected (via the 'type' argument).
 `,
 
-		CreateContext: CreateDataSource,
-		UpdateContext: UpdateDataSource,
-		DeleteContext: DeleteDataSource,
-		ReadContext:   ReadDataSource,
+		CreateContext:  CreateDataSource,
+		UpdateContext:  UpdateDataSource,
+		DeleteContext:  DeleteDataSource,
+		ReadContext:    ReadDataSource,
+		StateUpgraders: []schema.StateUpgrader{resourceDataSourceV0Upgrader},
+		SchemaVersion:  1,
 
 		// Import either by ID or UID
 		Importer: &schema.ResourceImporter{
@@ -704,3 +706,59 @@ func makeSecureJSONData(d *schema.ResourceData) gapi.SecureJSONData {
 		TLSClientKey:      d.Get("secure_json_data.0.tls_client_key").(string),
 	}
 }
+
+// TSDB Version and Resolution used to be strings, but now are integers.
+func resourceDataSourceV0Schema() *schema.Resource {
+	return &schema.Resource{
+		Schema: map[string]*schema.Schema{
+			"json_data": {
+				Type:     schema.TypeList,
+				Optional: true,
+				Elem: &schema.Resource{
+					Schema: map[string]*schema.Schema{
+						"tsdb_resolution": {
+							Type:        schema.TypeInt,
+							Optional:    true,
+							Description: "(OpenTSDB) Resolution.",
+						},
+						"tsdb_version": {
+							Type:        schema.TypeInt,
+							Optional:    true,
+							Description: "(OpenTSDB) Version.",
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
+var resourceDataSourceV0Upgrader = schema.StateUpgrader{
+	Version: 0,
+	Type:    resourceDataSourceV0Schema().CoreConfigSchema().ImpliedType(),
+	Upgrade: func(ctx context.Context, rawState map[string]interface{}, meta interface{}) (map[string]interface{}, error) {
+		convertToInt := func(m map[string]interface{}, key string) {
+			if value, hasValue := m[key]; hasValue {
+				m[key] = 0
+				if valueStr, ok := value.(string); ok {
+					if valueInt, err := strconv.Atoi(valueStr); err == nil {
+						m[key] = valueInt
+					}
+				}
+			}
+		}
+
+		var jsonData map[string]interface{}
+		if jsonDataList, ok := rawState["json_data"].([]interface{}); ok && len(jsonDataList) > 0 {
+			jsonData = jsonDataList[0].(map[string]interface{})
+		} else if jsonDataMap, ok := rawState["json_data"].(map[string]interface{}); ok {
+			jsonData = jsonDataMap
+		}
+		if jsonData != nil {
+			convertToInt(jsonData, "tsdb_version")
+			convertToInt(jsonData, "tsdb_resolution")
+		}
+
+		return rawState, nil
+	},
+}

grafana/resource_data_source_test.go

@@ -2,6 +2,7 @@ package grafana
 
 import (
 	"fmt"
+	"reflect"
 	"strconv"
 	"testing"
 
@@ -566,6 +567,133 @@ func TestAccDataSource_basic(t *testing.T) {
 	}
 }
 
+func TestDatasourceMigrationV0(t *testing.T) {
+	cases := []struct {
+		name     string
+		state    map[string]interface{}
+		expected map[string]interface{}
+	}{
+		{
+			name: "no json data",
+			state: map[string]interface{}{
+				"name": "test",
+				"type": "prometheus",
+			},
+			expected: map[string]interface{}{
+				"name": "test",
+				"type": "prometheus",
+			},
+		},
+		{
+			name: "no tsdb fields",
+			state: map[string]interface{}{
+				"name": "test",
+				"type": "prometheus",
+				"json_data": []map[string]interface{}{
+					{
+						"url": "http://localhost:9090",
+					},
+				},
+			},
+			expected: map[string]interface{}{
+				"name": "test",
+				"type": "prometheus",
+				"json_data": []map[string]interface{}{
+					{
+						"url": "http://localhost:9090",
+					},
+				},
+			},
+		},
+		{
+			name: "nil or empty tsdb fields",
+			state: map[string]interface{}{
+				"name": "test",
+				"type": "test",
+				"json_data": []map[string]interface{}{
+					{
+						"tsdb_version":    "",
+						"tsdb_resolution": nil,
+						"url":             "http://localhost:9090",
+					},
+				},
+			},
+			expected: map[string]interface{}{
+				"name": "test",
+				"type": "test",
+				"json_data": []map[string]interface{}{
+					{
+						"tsdb_version":    0,
+						"tsdb_resolution": 0,
+						"url":             "http://localhost:9090",
+					},
+				},
+			},
+		},
+		{
+			name: "already int",
+			state: map[string]interface{}{
+				"name": "test",
+				"type": "test",
+				"json_data": []map[string]interface{}{
+					{
+						"tsdb_version":    0,
+						"tsdb_resolution": 2,
+						"url":             "http://localhost:9090",
+					},
+				},
+			},
+			expected: map[string]interface{}{
+				"name": "test",
+				"type": "test",
+				"json_data": []map[string]interface{}{
+					{
+						"tsdb_version":    0,
+						"tsdb_resolution": 2,
+						"url":             "http://localhost:9090",
+					},
+				},
+			},
+		},
+		{
+			name: "migration",
+			state: map[string]interface{}{
+				"name": "test",
+				"type": "test",
+				"json_data": []map[string]interface{}{
+					{
+						"tsdb_version":    "0",
+						"tsdb_resolution": "2",
+						"url":             "http://localhost:9090",
+					},
+				},
+			},
+			expected: map[string]interface{}{
+				"name": "test",
+				"type": "test",
+				"json_data": []map[string]interface{}{
+					{
+						"tsdb_version":    0,
+						"tsdb_resolution": 2,
+						"url":             "http://localhost:9090",
+					},
+				},
+			},
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			actual, err := resourceDataSourceV0Upgrader.Upgrade(nil, tc.expected, nil)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if !reflect.DeepEqual(actual, tc.expected) {
+				t.Errorf("Expected %#v, got %#v", tc.expected, actual)
+			}
+		})
+	}
+}
+
 func testAccDataSourceCheckExists(rn string, dataSource *gapi.DataSource) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		rs, ok := s.RootModule().Resources[rn]