feat: make plugin version optional - installs latest version (#2315)

* feat: make plugin version optional - installs latest version

* docs: version won't auto-update

* ref: check plugin catalog latest version in read

* ref: only fetch catalog plugin version when desired version is the latest

Author: s4kh

docs/resources/cloud_plugin_installation.md

@@ -38,7 +38,10 @@ resource "grafana_cloud_plugin_installation" "test" {
 
 - `slug` (String) Slug of the plugin to be installed.
 - `stack_slug` (String) The stack id to which the plugin should be installed.
-- `version` (String) Version of the plugin to be installed.
+
+### Optional
+
+- `version` (String) Version of the plugin to be installed. Defaults to 'latest' and installs the most recent version. Terraform will detect new version as drift for plan/apply. Defaults to `latest`.
 
 ### Read-Only
 

internal/resources/cloud/resource_cloud_plugin_installation.go

@@ -19,6 +19,8 @@ var (
 	)
 )
 
+const LatestVersion = "latest"
+
 func resourcePluginInstallation() *common.Resource {
 	schema := &schema.Resource{
 		Description: `
@@ -46,9 +48,10 @@ Required access policy scopes:
 				ForceNew:    true,
 			},
 			"version": {
-				Description: "Version of the plugin to be installed.",
+				Description: "Version of the plugin to be installed. Defaults to 'latest' and installs the most recent version. Terraform will detect new version as drift for plan/apply.",
 				Type:        schema.TypeString,
-				Required:    true,
+				Optional:    true,
+				Default:     LatestVersion,
 				ForceNew:    true,
 			},
 		},
@@ -92,10 +95,11 @@ func listStackPlugins(ctx context.Context, client *gcom.APIClient, data *ListerD
 func resourcePluginInstallationCreate(ctx context.Context, d *schema.ResourceData, client *gcom.APIClient) diag.Diagnostics {
 	stackSlug := d.Get("stack_slug").(string)
 	pluginSlug := d.Get("slug").(string)
+	version := d.Get("version").(string)
 
 	req := gcom.PostInstancePluginsRequest{
 		Plugin:  pluginSlug,
-		Version: common.Ref(d.Get("version").(string)),
+		Version: common.Ref(version),
 	}
 
 	err := retry.RetryContext(ctx, 2*time.Minute, func() *retry.RetryError {
@@ -133,10 +137,24 @@ func resourcePluginInstallationRead(ctx context.Context, d *schema.ResourceData,
 	if err, shouldReturn := common.CheckReadError("plugin", d, err); shouldReturn {
 		return err
 	}
+	desiredVersion := d.Get("version").(string)
+	catalogVersion := ""
+	if desiredVersion == LatestVersion {
+		catalogPlugin, _, err := client.PluginsAPI.GetPlugin(ctx, pluginSlug.(string)).Execute()
+		if err, shouldReturn := common.CheckReadError("plugin", d, err); shouldReturn {
+			return err
+		}
+		catalogVersion = catalogPlugin.Version
+	}
 
 	d.Set("stack_slug", installation.InstanceSlug)
 	d.Set("slug", installation.PluginSlug)
-	d.Set("version", installation.Version)
+
+	if desiredVersion == LatestVersion && installation.Version == catalogVersion {
+		d.Set("version", LatestVersion)
+	} else {
+		d.Set("version", installation.Version)
+	}
 	d.SetId(resourcePluginInstallationID.Make(stackSlug, pluginSlug))
 
 	return nil

internal/resources/cloud/resource_cloud_plugin_test.go

@@ -36,6 +36,17 @@ func TestAccResourcePluginInstallation(t *testing.T) {
 					resource.TestCheckResourceAttr("grafana_cloud_plugin_installation.test-installation", "slug", "grafana-googlesheets-datasource"),
 					resource.TestCheckResourceAttr("grafana_cloud_plugin_installation.test-installation", "version", "1.2.5")),
 			},
+			{
+				Config: testAccGrafanaCloudPluginInstallationLatest(stackSlug, "grafana-clock-panel"),
+				Check: resource.ComposeTestCheckFunc(
+					testAccStackCheckExists("grafana_cloud_stack.test", &stack),
+					testAccCloudPluginInstallationCheckExists(stackSlug, "grafana-clock-panel"),
+					resource.TestCheckResourceAttrSet("grafana_cloud_plugin_installation.test-installation-no-version", "id"),
+					resource.TestCheckResourceAttr("grafana_cloud_plugin_installation.test-installation-no-version", "stack_slug", stackSlug),
+					resource.TestCheckResourceAttr("grafana_cloud_plugin_installation.test-installation-no-version", "slug", pluginSlug),
+					resource.TestCheckResourceAttr("grafana_cloud_plugin_installation.test-installation-no-version", "version", "latest"),
+				),
+			},
 			{
 				ResourceName:      "grafana_cloud_plugin_installation.test-installation",
 				ImportState:       true,
@@ -95,6 +106,7 @@ func testAccGrafanaCloudPluginInstallation(stackSlug, name, version string) stri
 		resource "grafana_cloud_stack" "test" {
 			name  = "%[1]s"
 			slug  = "%[1]s"
+			delete_protection = false
 			wait_for_readiness = false
 		}
 
@@ -105,3 +117,18 @@ func testAccGrafanaCloudPluginInstallation(stackSlug, name, version string) stri
 		}
 	`, stackSlug, name, version)
 }
+
+func testAccGrafanaCloudPluginInstallationLatest(stackSlug, name string) string {
+	return fmt.Sprintf(`
+		resource "grafana_cloud_stack" "test" {
+			name  = "%[1]s"
+			slug  = "%[1]s"
+			delete_protection = false
+			wait_for_readiness = false
+		}
+        resource "grafana_cloud_plugin_installation" "test-installation-no-version" {
+            stack_slug = grafana_cloud_stack.test.slug
+            slug       = "%[2]s"
+        }
+    `, stackSlug, name)
+}