Automatically fetch stack version in ecctl deployment create --version isn't provided (#761)

When `--version` is not provided to `ecctl deployment create`, the command now automatically fetches the latest available stack version from the API and uses it. This avoids a confusing error when users omit the `--version` flag.

Key changes in `create.go`:
- Added a call to `getLatestStackVersion()` that queries `stackapi.List` for available stack versions and picks the first (latest) one.
- The auto-fetch is skipped when `--file` is provided, since file-based payloads carry their own version.
- Prints a message to stderr (`--version not set, using latest: X.Y.Z`) so the user knows which version was selected.

Author: mlliarm

cmd/deployment/create.go

@@ -25,6 +25,7 @@ import (
 	"github.com/blang/semver/v4"
 	"github.com/elastic/cloud-sdk-go/pkg/api/deploymentapi"
 	"github.com/elastic/cloud-sdk-go/pkg/api/deploymentapi/deptemplateapi"
+	"github.com/elastic/cloud-sdk-go/pkg/api/stackapi"
 	"github.com/elastic/cloud-sdk-go/pkg/models"
 	"github.com/elastic/cloud-sdk-go/pkg/multierror"
 	sdkcmdutil "github.com/elastic/cloud-sdk-go/pkg/util/cmdutil"
@@ -45,8 +46,18 @@ var createCmd = &cobra.Command{
 		generatePayload, _ := cmd.Flags().GetBool("generate-payload")
 		name, _ := cmd.Flags().GetString("name")
 		version, _ := cmd.Flags().GetString("version")
+		file, _ := cmd.Flags().GetString("file")
 		region := ecctl.Get().Config.Region
 
+		if version == "" && file == "" {
+			var err error
+			version, err = getLatestStackVersion(region)
+			if err != nil {
+				return err
+			}
+			_, _ = fmt.Fprintf(cmd.ErrOrStderr(), "--version not set, using latest: %s\n", version)
+		}
+
 		payload, err := newCreatePayload(cmd, version, region)
 		if err != nil {
 			return err
@@ -111,6 +122,21 @@ func initFlags() {
 	createCmd.Flags().Bool("minimum-size", false, "Shrink each Elasticsearch topology element to its minimum allowed size")
 }
 
+func getLatestStackVersion(region string) (string, error) {
+	stacks, err := stackapi.List(stackapi.ListParams{
+		API:    ecctl.Get().API,
+		Region: region,
+	})
+	if err != nil {
+		return "", fmt.Errorf("unable to fetch stack versions: %w", err)
+	}
+	if len(stacks.Stacks) == 0 {
+		return "", errors.New("no stack versions available")
+	}
+	// List returns stacks sorted descending, so first is latest.
+	return stacks.Stacks[0].Version, nil
+}
+
 func getDefaultTemplate(region, stackVersion string) (string, error) {
 	showHidden := false
 	templates, err := deptemplateapi.List(deptemplateapi.ListParams{

cmd/deployment/create_test.go

@@ -272,6 +272,79 @@ Deployment [%s] - [Apm][%s]: running step "waiting-for-some-step" (Plan duration
 				).Error(),
 			},
 		},
+		{
+			name: "succeeds creating a deployment without --version by fetching latest stack version",
+			args: testutils.Args{
+				Cmd: createCmd,
+				Args: []string{
+					"create",
+					"--request-id=some_request_id",
+					"--deployment-template=aws-io-optimized-v2",
+					"--name=with_default",
+				},
+				Cfg: testutils.MockCfg{Responses: []mock.Response{
+					{
+						Response: http.Response{
+							StatusCode: 200,
+							Body: mock.NewStructBody(models.StackVersionConfigs{
+								Stacks: []*models.StackVersionConfig{
+									{Version: "7.8.0"},
+									{Version: "7.7.0"},
+									{Version: "7.6.0"},
+								},
+							}),
+						},
+						Assert: &mock.RequestAssertion{
+							Method: "GET",
+							Header: api.DefaultReadMockHeaders,
+							Path:   "/api/v1/regions/ece-region/stack/versions",
+							Host:   api.DefaultMockHost,
+							Query: url.Values{
+								"show_deleted": {"false"},
+							},
+						},
+					},
+					{
+						Response: http.Response{
+							StatusCode: 200,
+							Body:       mock.NewByteBody(awsIoOptimisedTemplate),
+						},
+						Assert: &mock.RequestAssertion{
+							Method: "GET",
+							Header: api.DefaultReadMockHeaders,
+							Path:   "/api/v1/deployments/templates/aws-io-optimized-v2",
+							Host:   api.DefaultMockHost,
+							Query: url.Values{
+								"region":                       {"ece-region"},
+								"show_instance_configurations": {"true"},
+								"show_max_zones":               {"false"},
+								"stack_version":                {"7.8.0"},
+							},
+						},
+					},
+					{
+						Response: http.Response{
+							StatusCode: 201,
+							Body:       mock.NewStructBody(defaultCreateResponse),
+						},
+						Assert: &mock.RequestAssertion{
+							Method: "POST",
+							Header: api.DefaultWriteMockHeaders,
+							Body:   mock.NewStringBody(`{"name":"with_default","resources":{"apm":[{"elasticsearch_cluster_ref_id":"main-elasticsearch","plan":{"apm":{"version":"7.8.0"},"cluster_topology":[{"instance_configuration_id":"aws.apm.r5d","size":{"resource":"memory","value":512},"zone_count":1}]},"ref_id":"main-apm","region":"us-east-1"}],"appsearch":null,"elasticsearch":[{"plan":{"autoscaling_enabled":false,"cluster_topology":[{"id":"coordinating","instance_configuration_id":"aws.coordinating.m5d","node_roles":null,"node_type":{"data":false,"ingest":true,"master":false},"size":{"resource":"memory","value":0},"topology_element_control":{"min":{"resource":"memory","value":0}},"zone_count":2},{"autoscaling_max":{"resource":"memory","value":118784},"elasticsearch":{"node_attributes":{"data":"hot"}},"id":"hot_content","instance_configuration_id":"aws.data.highio.i3","node_roles":null,"node_type":{"data":true,"ingest":true,"master":true},"size":{"resource":"memory","value":8192},"topology_element_control":{"min":{"resource":"memory","value":1024}},"zone_count":2},{"autoscaling_max":{"resource":"memory","value":118784},"elasticsearch":{"node_attributes":{"data":"warm"}},"id":"warm","instance_configuration_id":"aws.data.highstorage.d3","node_roles":null,"node_type":{"data":true,"ingest":false,"master":false},"size":{"resource":"memory","value":0},"topology_element_control":{"min":{"resource":"memory","value":0}},"zone_count":2},{"autoscaling_max":{"resource":"memory","value":59392},"elasticsearch":{"node_attributes":{"data":"cold"}},"id":"cold","instance_configuration_id":"aws.data.highstorage.d3","node_roles":null,"node_type":{"data":true,"ingest":false,"master":false},"size":{"resource":"memory","value":0},"topology_element_control":{"min":{"resource":"memory","value":0}},"zone_count":1},{"id":"master","instance_configuration_id":"aws.master.r5d","node_roles":null,"node_type":{"data":false,"ingest":false,"master":true},"size":{"resource":"memory","value":0},"topology_element_control":{"min":{"resource":"memory","value":0}},"zone_count":3},{"autoscaling_max":{"resource":"memory","value":61440},"autoscaling_min":{"resource":"memory","value":0},"id":"ml","instance_configuration_id":"aws.ml.m5d","node_roles":null,"node_type":{"data":false,"ingest":false,"master":false,"ml":true},"size":{"resource":"memory","value":0},"topology_element_control":{"min":{"resource":"memory","value":0}},"zone_count":1}],"deployment_template":{"id":"aws-io-optimized-v2"},"elasticsearch":{"version":"7.8.0"}},"ref_id":"main-elasticsearch","region":"us-east-1","settings":{"dedicated_masters_threshold":6}}],"enterprise_search":[{"elasticsearch_cluster_ref_id":"main-elasticsearch","plan":{"cluster_topology":[{"instance_configuration_id":"aws.enterprisesearch.m5d","node_type":{"appserver":true,"connector":true,"worker":true},"size":{"resource":"memory","value":0},"zone_count":2}],"enterprise_search":{"version":"7.8.0"}},"ref_id":"main-enterprise_search","region":"us-east-1"}],"integrations_server":null,"kibana":[{"elasticsearch_cluster_ref_id":"main-elasticsearch","plan":{"cluster_topology":[{"instance_configuration_id":"aws.kibana.r5d","size":{"resource":"memory","value":1024},"zone_count":1}],"kibana":{"version":"7.8.0"}},"ref_id":"main-kibana","region":"us-east-1"}]}}` + "\n"),
+							Path:   "/api/v1/deployments",
+							Host:   api.DefaultMockHost,
+							Query: url.Values{
+								"request_id": {"some_request_id"},
+							},
+						},
+					},
+				}},
+			},
+			want: testutils.Assertion{
+				Stdout: string(defaultCreateResponseBytes),
+				Stderr: "--version not set, using latest: 7.8.0\n",
+			},
+		},
 		{
 			name: "succeeds creating a deployment without --deployment-template by auto-selecting default",
 			args: testutils.Args{