KSQL-14849: add 'confluent ksql cluster update --csu N' command

internal/ksql/command_cluster.go

@@ -21,6 +21,7 @@ func newClusterCommand(cfg *config.Config, prerunner pcmd.PreRunner) *cobra.Comm
 		cmd.AddCommand(c.newDeleteCommand())
 		cmd.AddCommand(c.newDescribeCommand())
 		cmd.AddCommand(c.newListCommand())
+		cmd.AddCommand(c.newUpdateCommand())
 	} else {
 		c := &ksqlCommand{pcmd.NewAuthenticatedWithMDSCLICommand(cmd, prerunner)}
 		cmd.AddCommand(c.newListCommandOnPrem())

internal/ksql/command_cluster_update.go

@@ -0,0 +1,144 @@
+package ksql
+
+import (
+	"fmt"
+	"sort"
+
+	"github.com/spf13/cobra"
+
+	pcmd "github.com/confluentinc/cli/v4/pkg/cmd"
+	"github.com/confluentinc/cli/v4/pkg/errors"
+	"github.com/confluentinc/cli/v4/pkg/examples"
+	"github.com/confluentinc/cli/v4/pkg/output"
+)
+
+// Valid CSU sizes that customers may target via self-serve cluster update.
+// Mirrors the server-side authoritative list in cc-control-plane-ksql:
+// internal/service/update_ksql_cluster_resize.go::validCSUSizes.
+// Values 1, 2 are legacy and not user-selectable. Values above 28 still
+// require a support ticket.
+//
+//nolint:gochecknoglobals
+var validCsuSizes = []int32{4, 8, 12, 16, 20, 24, 28}
+
+const csuSupportTicketMessage = "CSU values above 28 require a support ticket. " +
+	"Please contact Confluent Support to request a larger cluster size."
+
+func (c *ksqlCommand) newUpdateCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:               "update <id>",
+		Short:             "Update a ksqlDB cluster.",
+		Long:              buildUpdateLongDescription(),
+		Args:              cobra.ExactArgs(1),
+		ValidArgsFunction: pcmd.NewValidArgsFunction(c.validArgs),
+		RunE:              c.update,
+		Example: examples.BuildExampleString(
+			examples.Example{
+				Text: `Resize ksqlDB cluster "lksqlc-12345" to 8 CSUs.`,
+				Code: "confluent ksql cluster update lksqlc-12345 --csu 8",
+			},
+		),
+	}
+
+	cmd.Flags().Int32("csu", 0, fmt.Sprintf(
+		"Target number of CSUs for the cluster. Valid values: %s.",
+		formatCsuList(validCsuSizes)))
+	pcmd.AddContextFlag(cmd, c.CLICommand)
+	pcmd.AddEnvironmentFlag(cmd, c.AuthenticatedCLICommand)
+	pcmd.AddOutputFlag(cmd)
+
+	cobra.CheckErr(cmd.MarkFlagRequired("csu"))
+
+	return cmd
+}
+
+func buildUpdateLongDescription() string {
+	return fmt.Sprintf(
+		`Update an existing ksqlDB cluster. Currently only the CSU count may be
+modified, and only to larger sizes (shrink is not supported).
+
+Valid CSU values are %s. Larger sizes require a support ticket.
+The cluster will undergo a rolling restart to apply the new size; the
+command returns once the resize has been accepted by the control plane.`,
+		formatCsuList(validCsuSizes))
+}
+
+func (c *ksqlCommand) update(cmd *cobra.Command, args []string) error {
+	csu, err := cmd.Flags().GetInt32("csu")
+	if err != nil {
+		return err
+	}
+	if err := validateCsuForUpdate(csu); err != nil {
+		return err
+	}
+
+	environmentId, err := c.Context.EnvironmentId()
+	if err != nil {
+		return err
+	}
+
+	clusterId := args[0]
+
+	// Pre-check current CSU so we can short-circuit a no-op locally before
+	// issuing the PATCH. The server-side validator also rejects no-op resizes
+	// with 400 ("new CSU size is the same as old CSU size, no-op"), but a
+	// client-side check produces a clearer message and avoids a wasted API
+	// round trip. Note: shrink is not supported server-side either.
+	current, err := c.V2Client.DescribeKsqlCluster(clusterId, environmentId)
+	if err != nil {
+		return errors.CatchKSQLNotFoundError(err, clusterId)
+	}
+	currentCsu := current.Spec.GetCsu()
+	if currentCsu == csu {
+		return fmt.Errorf("ksqlDB cluster %q is already at %d CSUs; no change requested",
+			clusterId, csu)
+	}
+	if csu < currentCsu {
+		return fmt.Errorf("ksqlDB cluster %q is currently %d CSUs; shrinking is not supported "+
+			"(target %d < current %d)", clusterId, currentCsu, csu, currentCsu)
+	}
+
+	output.ErrPrintf(c.Config.EnableColor,
+		"Resizing ksqlDB cluster %q from %d to %d CSUs. A rolling restart will be "+
+			"performed asynchronously; the cluster will continue serving queries during the resize.\n",
+		clusterId, currentCsu, csu)
+
+	cluster, err := c.V2Client.UpdateKsqlCluster(clusterId, environmentId, csu)
+	if err != nil {
+		return err
+	}
+
+	table := output.NewTable(cmd)
+	table.Add(c.formatClusterForDisplayAndList(&cluster))
+	return table.Print()
+}
+
+// validateCsuForUpdate returns nil if csu is in validCsuSizes, and a
+// customer-safe error otherwise. The server-side check in
+// cc-control-plane-ksql is authoritative; this client-side validation exists
+// to fail fast with a clearer message before issuing the API call.
+func validateCsuForUpdate(csu int32) error {
+	if csu > 28 {
+		return fmt.Errorf("%d CSUs: %s", csu, csuSupportTicketMessage)
+	}
+	for _, valid := range validCsuSizes {
+		if csu == valid {
+			return nil
+		}
+	}
+	return fmt.Errorf("%d is not a valid CSU size for cluster update. Valid sizes are %s",
+		csu, formatCsuList(validCsuSizes))
+}
+
+func formatCsuList(sizes []int32) string {
+	sorted := append([]int32(nil), sizes...)
+	sort.Slice(sorted, func(i, j int) bool { return sorted[i] < sorted[j] })
+	out := ""
+	for i, s := range sorted {
+		if i > 0 {
+			out += ", "
+		}
+		out += fmt.Sprintf("%d", s)
+	}
+	return out
+}

internal/ksql/command_cluster_update_test.go

@@ -0,0 +1,78 @@
+package ksql
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestValidateCsuForUpdate(t *testing.T) {
+	tests := []struct {
+		name        string
+		csu         int32
+		expectErr   bool
+		errContains string
+	}{
+		{name: "valid 4", csu: 4},
+		{name: "valid 8", csu: 8},
+		{name: "valid 12", csu: 12},
+		{name: "valid 16", csu: 16},
+		{name: "valid 20", csu: 20},
+		{name: "valid 24", csu: 24},
+		{name: "valid 28", csu: 28},
+		{
+			name:        "legacy size 1 rejected",
+			csu:         1,
+			expectErr:   true,
+			errContains: "not a valid CSU size",
+		},
+		{
+			name:        "legacy size 2 rejected",
+			csu:         2,
+			expectErr:   true,
+			errContains: "not a valid CSU size",
+		},
+		{
+			name:        "in-range but non-canonical (5) rejected",
+			csu:         5,
+			expectErr:   true,
+			errContains: "not a valid CSU size",
+		},
+		{
+			name:        "in-range but non-canonical (10) rejected",
+			csu:         10,
+			expectErr:   true,
+			errContains: "not a valid CSU size",
+		},
+		{
+			name:        "above 28 routes to support-ticket message",
+			csu:         32,
+			expectErr:   true,
+			errContains: "support ticket",
+		},
+		{
+			name:        "well above ceiling routes to support-ticket message",
+			csu:         128,
+			expectErr:   true,
+			errContains: "support ticket",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			err := validateCsuForUpdate(tc.csu)
+			if tc.expectErr {
+				require.Error(t, err)
+				require.Contains(t, err.Error(), tc.errContains)
+			} else {
+				require.NoError(t, err)
+			}
+		})
+	}
+}
+
+func TestFormatCsuList(t *testing.T) {
+	require.Equal(t, "4, 8, 12, 16, 20, 24, 28", formatCsuList(validCsuSizes))
+	// Input order should not matter; output is sorted ascending.
+	require.Equal(t, "4, 8, 16", formatCsuList([]int32{16, 4, 8}))
+}

pkg/ccloudv2/ksql.go

@@ -2,6 +2,7 @@ package ccloudv2
 
 import (
 	"context"
+	"fmt"
 	"net/http"
 
 	ksqlv2 "github.com/confluentinc/ccloud-sdk-go-v2/ksql/v2"
@@ -73,3 +74,29 @@ func (c *Client) CreateKsqlCluster(displayName, environmentId, kafkaClusterId, c
 	res, httpResp, err := c.KsqlClient.ClustersKsqldbcmV2Api.CreateKsqldbcmV2Cluster(c.ksqlApiContext()).KsqldbcmV2Cluster(cluster).Execute()
 	return res, errors.CatchCCloudV2Error(err, httpResp)
 }
+
+// UpdateKsqlCluster issues PATCH /ksqldbcm/v2/clusters/{id} with {"spec":{"csu": N}}
+// to trigger a self-serve cluster resize.
+//
+// The PATCH operation is not yet available in ccloud-sdk-go-v2/ksql/v2 — it is
+// being added in cc-api PR #2507 (KSQL-14844), after which the SDK needs to be
+// regenerated and the ksql module dependency in go.mod bumped. Until that
+// lands, calling this method returns a clear, customer-safe error rather than
+// an HTTP failure. See KSQL-14849 for the work item.
+//
+// Wiring instructions once the SDK is regenerated:
+//
+//	cluster := ksqlv2.KsqldbcmV2Cluster{Spec: &ksqlv2.KsqldbcmV2ClusterSpec{Csu: &csu}}
+//	res, httpResp, err := c.KsqlClient.ClustersKsqldbcmV2Api.
+//	    UpdateKsqldbcmV2Cluster(c.ksqlApiContext(), id).
+//	    KsqldbcmV2ClusterUpdate(cluster).Environment(environmentId).Execute()
+//	return res, errors.CatchCCloudV2Error(err, httpResp)
+func (c *Client) UpdateKsqlCluster(id, environmentId string, csu int32) (ksqlv2.KsqldbcmV2Cluster, error) {
+	_ = id
+	_ = environmentId
+	_ = csu
+	return ksqlv2.KsqldbcmV2Cluster{}, fmt.Errorf(
+		"ksqlDB cluster update is not yet available in this CLI build; " +
+			"this command is pending a ccloud-sdk-go-v2/ksql regeneration " +
+			"after cc-api PR #2507 (KSQL-14844) merges. Track KSQL-14849 for status.")
+}