Allow importing a datasource either by ID or UID (#396)

* Allow importing a datasource either by ID or UID
Closes #252

* Lint

Author: julienduchesne

docs/resources/data_source.md

@@ -183,4 +183,11 @@ Optional:
 - **tls_client_cert** (String, Sensitive) (All) TLS Client cert for outgoing requests.
 - **tls_client_key** (String, Sensitive) (All) TLS Client key for outgoing requests.
 
+## Import
 
+Import is supported using the following syntax:
+
+```shell
+terraform import grafana_data_source.by_integer_id {{datasource id}}
+terraform import grafana_data_source.by_uid {{datasource uid}}
+```

examples/resources/grafana_data_source/import.sh

@@ -0,0 +1,2 @@
+terraform import grafana_data_source.by_integer_id {{datasource id}}
+terraform import grafana_data_source.by_uid {{datasource uid}}

grafana/resource_data_source.go

@@ -31,6 +31,23 @@ source selected (via the 'type' argument).
 		DeleteContext: DeleteDataSource,
 		ReadContext:   ReadDataSource,
 
+		// Import either by ID or UID
+		Importer: &schema.ResourceImporter{
+			StateContext: func(c context.Context, rd *schema.ResourceData, meta interface{}) ([]*schema.ResourceData, error) {
+				_, err := strconv.ParseInt(rd.Id(), 10, 64)
+				if err != nil {
+					// If the ID is not a number, then it may be a UID
+					client := meta.(*client).gapi
+					ds, err := client.DataSourceByUID(rd.Id())
+					if err != nil {
+						return nil, fmt.Errorf("failed to find datasource by ID or UID '%s': %w", rd.Id(), err)
+					}
+					rd.SetId(strconv.FormatInt(ds.ID, 10))
+				}
+				return []*schema.ResourceData{rd}, nil
+			},
+		},
+
 		Schema: map[string]*schema.Schema{
 			"access_mode": {
 				Type:        schema.TypeString,

grafana/resource_data_source_test.go

@@ -540,6 +540,27 @@ func TestAccDataSource_basic(t *testing.T) {
 						append(checks, test.additionalChecks...)...,
 					),
 				},
+				// Test import using ID
+				{
+					ResourceName: test.resource,
+					ImportState:  true,
+				},
+				// Test import using UID
+				{
+					ResourceName: test.resource,
+					ImportState:  true,
+					ImportStateIdFunc: func(s *terraform.State) (string, error) {
+						rs, ok := s.RootModule().Resources[test.resource]
+						if !ok {
+							return "", fmt.Errorf("resource not found: %s", test.resource)
+						}
+
+						if rs.Primary.ID == "" {
+							return "", fmt.Errorf("resource id not set")
+						}
+						return rs.Primary.Attributes["uid"], nil
+					},
+				},
 			},
 		})
 	}