feat(plugin): surface installed plugins and the marketplace on the landing screen

The no-argument landing now reflects the plugins a user has added: each
installed plugin is listed as a runnable `datumctl <command>` verb badged
with the catalog it came from, and a new "Extend datumctl" entry plus a few
tips point at `datumctl plugin browse`. The plugin list is read locally and
best-effort, so it never slows down or breaks the landing.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: scotwells

internal/cmd/landing.go

@@ -4,12 +4,14 @@ import (
 	"fmt"
 	"io"
 	"math/rand"
+	"sort"
 	"strings"
 	"time"
 
 	"github.com/spf13/cobra"
 
 	"go.datum.net/datumctl/internal/datumconfig"
+	"go.datum.net/datumctl/internal/pluginstore"
 )
 
 // runLanding prints a contextual welcome when `datumctl` is invoked with no
@@ -113,19 +115,81 @@ func printLoggedInLanding(out io.Writer, cfg *datumconfig.ConfigV1Beta1, session
 		fmt.Fprintln(out, "                         datumctl describe <resource> <name>")
 		fmt.Fprintln(out, "  Ship something         datumctl apply -f file.yaml")
 		fmt.Fprintln(out, "                         datumctl create <resource> ...")
+		fmt.Fprintln(out, "  Extend datumctl        datumctl plugin browse")
 		fmt.Fprintln(out, "  Explore the API        datumctl api-resources")
 		fmt.Fprintln(out, "  Follow the audit trail datumctl activity")
 		fmt.Fprintln(out, "  Switch context         datumctl ctx")
 	}
 	fmt.Fprintln(out, "  Switch account         datumctl auth switch")
 	fmt.Fprintln(out)
 
+	// Installed plugins become `datumctl <command>` verbs, so reflect the user's
+	// own setup on the landing. Best-effort and local-only — never blocks the
+	// landing on a missing or unreadable plugin store.
+	printInstalledPlugins(out)
+
 	fmt.Fprintf(out, "Tip: %s\n", pickTip(time.Now().UnixNano()))
 	fmt.Fprintln(out)
 
 	fmt.Fprintln(out, "Run 'datumctl --help' for the full command reference.")
 }
 
+// printInstalledPlugins renders a "Your plugins" block listing each installed
+// plugin as a runnable `datumctl <command>` verb with the catalog it came from.
+// It is best-effort and local-only: any error reading the plugin store, or no
+// installed plugins, simply prints nothing.
+func printInstalledPlugins(out io.Writer) {
+	dir, err := pluginstore.PluginsDir("")
+	if err != nil {
+		return
+	}
+	manifest, err := pluginstore.Load(dir)
+	if err != nil || manifest == nil || len(manifest.Plugins) == 0 {
+		return
+	}
+
+	names := make([]string, 0, len(manifest.Plugins))
+	for name := range manifest.Plugins {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+
+	// Pad the command column so the source labels line up.
+	cmdWidth := 0
+	for _, name := range names {
+		if w := len("datumctl " + name); w > cmdWidth {
+			cmdWidth = w
+		}
+	}
+
+	for i, name := range names {
+		label := ""
+		if i == 0 {
+			label = "Your plugins"
+		}
+		command := "datumctl " + name
+		fmt.Fprintf(out, "  %-22s %-*s (%s)\n", label, cmdWidth, command, landingPluginSource(manifest.Plugins[name]))
+	}
+	fmt.Fprintln(out)
+}
+
+// landingPluginSource returns a short catalog label for an installed plugin,
+// mirroring how `plugin list` labels provenance.
+func landingPluginSource(entry *pluginstore.InstalledPlugin) string {
+	if entry == nil {
+		return ""
+	}
+	if entry.Catalog != "" {
+		return pluginstore.CanonicalCatalogName(entry.Catalog)
+	}
+	// Legacy records: a slash in Source means a direct GitHub install; otherwise
+	// it came from the curated official catalog.
+	if strings.Contains(entry.Source, "/") {
+		return "direct"
+	}
+	return pluginstore.OfficialCatalogName
+}
+
 // firstName returns the first whitespace-delimited token of full. Returns ""
 // for empty/whitespace input.
 func firstName(full string) string {
@@ -169,6 +233,10 @@ var landingTips = []string{
 	// Audit tips
 	"'datumctl activity' tails the audit trail across your whole control plane.",
 	"'datumctl activity --start-time now-1h' scopes the feed to the last hour.",
+	// Plugin / marketplace tips
+	"'datumctl plugin browse' explores plugins across every registered catalog.",
+	"'datumctl plugin search <keyword>' finds plugins to install from any catalog.",
+	"'datumctl plugin index add <name> <url>' registers a team or community catalog.",
 	// Power-user tips
 	"Set DATUM_PROJECT or DATUM_ORGANIZATION to override context for a single command.",
 	"'datumctl describe <resource> <name>' shows status conditions — handy for debugging.",

internal/cmd/landing_test.go

@@ -0,0 +1,108 @@
+package cmd
+
+import (
+	"bytes"
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"go.datum.net/datumctl/internal/pluginstore"
+)
+
+func seedPluginsManifest(t *testing.T, plugins map[string]*pluginstore.InstalledPlugin) {
+	t.Helper()
+	dir := t.TempDir()
+	t.Setenv("DATUMCTL_PLUGINS_DIR", dir)
+	data, err := json.MarshalIndent(pluginstore.Manifest{Plugins: plugins}, "", "  ")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(dir, "plugins.json"), data, 0o600); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestPrintInstalledPlugins_listsInstalledAsCommands(t *testing.T) {
+	seedPluginsManifest(t, map[string]*pluginstore.InstalledPlugin{
+		// Catalog "default" is the official catalog under its legacy alias; it must
+		// render with the canonical product-facing name "datum".
+		"dns":  {Catalog: "default", Version: "v1.2.3", Source: "datum"},
+		"ipam": {Catalog: "acme", Version: "v0.4.0", Source: "https://plugins.acme.example/index.yaml"},
+		// Legacy record with no catalog and a slashed source -> "direct".
+		"costs": {Source: "octo/datumctl-costs", Version: "v2.0.0"},
+	})
+
+	var buf bytes.Buffer
+	printInstalledPlugins(&buf)
+	out := buf.String()
+
+	if !strings.Contains(out, "Your plugins") {
+		t.Fatalf("expected a Your plugins block, got:\n%s", out)
+	}
+	// Each plugin is shown as a runnable `datumctl <command>` verb.
+	for _, cmd := range []string{"datumctl dns", "datumctl ipam", "datumctl costs"} {
+		if !strings.Contains(out, cmd) {
+			t.Errorf("expected %q in output:\n%s", cmd, out)
+		}
+	}
+	// Provenance is labelled, with the legacy "default" alias canonicalized.
+	for _, src := range []string{"(datum)", "(acme)", "(direct)"} {
+		if !strings.Contains(out, src) {
+			t.Errorf("expected source label %q in output:\n%s", src, out)
+		}
+	}
+	if strings.Contains(out, "(default)") {
+		t.Errorf("legacy 'default' catalog should render as 'datum', not 'default':\n%s", out)
+	}
+}
+
+func TestPrintInstalledPlugins_emptyWhenNoneInstalled(t *testing.T) {
+	seedPluginsManifest(t, map[string]*pluginstore.InstalledPlugin{})
+
+	var buf bytes.Buffer
+	printInstalledPlugins(&buf)
+
+	if buf.Len() != 0 {
+		t.Fatalf("expected no output when no plugins are installed, got:\n%s", buf.String())
+	}
+}
+
+func TestPrintInstalledPlugins_emptyWhenStoreUnreadable(t *testing.T) {
+	// Point the store at a path that cannot be a valid plugins dir; the landing
+	// must degrade silently rather than emit a partial or erroring block.
+	file := filepath.Join(t.TempDir(), "not-a-dir")
+	if err := os.WriteFile(file, []byte("x"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	t.Setenv("DATUMCTL_PLUGINS_DIR", filepath.Join(file, "nested"))
+
+	var buf bytes.Buffer
+	printInstalledPlugins(&buf)
+
+	if buf.Len() != 0 {
+		t.Fatalf("expected no output when the plugin store is unreadable, got:\n%s", buf.String())
+	}
+}
+
+func TestLandingPluginSource(t *testing.T) {
+	cases := []struct {
+		name  string
+		entry *pluginstore.InstalledPlugin
+		want  string
+	}{
+		{"nil", nil, ""},
+		{"catalog", &pluginstore.InstalledPlugin{Catalog: "acme"}, "acme"},
+		{"legacy default alias", &pluginstore.InstalledPlugin{Catalog: "default"}, "datum"},
+		{"legacy direct", &pluginstore.InstalledPlugin{Source: "octo/repo"}, "direct"},
+		{"legacy official", &pluginstore.InstalledPlugin{Source: "datum"}, pluginstore.OfficialCatalogName},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := landingPluginSource(tc.entry); got != tc.want {
+				t.Errorf("landingPluginSource = %q, want %q", got, tc.want)
+			}
+		})
+	}
+}