mesh-sdk/go/catalogue/hostname_seat_test.go

package catalogue

import (
	"strings"
	"testing"
)

// novox/hq ADR 0223 part 3: a machine's names are one seat's. The `hosts` module holding
// `node-hosts-file` became `hostname` holding `node-hostname`, which writes /etc/hostname beside the
// machine's own lines in /etc/hosts. The seat was renamed (ADR 0122), so what claims the old name — a
// manifest registered before the rename — still holds the one seat.

func withHostnameAlias(t *testing.T) {
	t.Helper()
	was := aliases
	t.Cleanup(func() { aliases = was })
	UseAliases(map[string]string{"node-hosts-file": "node-hostname"})
}

func TestTheHostsFilesFormerNameResolvesToTheHostnameSeat(t *testing.T) {
	if _, known := SeatNamed("node-hostname"); !known {
		t.Fatal("node-hostname is not in the mesh's set")
	}
	withHostnameAlias(t)
	seat, known := SeatNamed("node-hosts-file")
	if !known || seat.Name != "node-hostname" || seat.Scope != ScopeNode {
		t.Fatalf("the former name did not resolve: %+v %v", seat, known)
	}
	var verbs []string
	for _, v := range seat.Serves {
		verbs = append(verbs, v.Name)
	}
	if strings.Join(verbs, " ") != "entries add remove" {
		t.Errorf("the renamed seat serves %v; its verbs are unchanged", verbs)
	}
}

// One seat under either name: the module registered before the rename and the one after cannot both
// hold it on one machine.
func TestTheOldAndTheNewClaimantAreOneSeatOnAMachine(t *testing.T) {
	withHostnameAlias(t)
	cat := shelf(
		mod("hosts", nil, nil, nil, Claim{Name: "node-hosts-file"}),
		mod("hostname", nil, nil, nil, Claim{Name: "node-hostname"}),
	)
	_, err := Resolve(cat, []string{"hosts", "hostname"}, workstation(), World{})
	if err == nil || !strings.Contains(err.Error(), "node-hostname") {
		t.Errorf("hosts and hostname both held the machine's names on one machine: %v", err)
	}
	if _, err := Resolve(cat, []string{"hosts"}, workstation(), World{}); err != nil {
		t.Errorf("a machine still assigned hosts under the old name does not resolve: %v", err)
	}
}

// The catalogue's module: /etc/hostname is the operator's `hostname` setting. Without it the module is
// left out, naming the key — the mesh never renames a machine on its own — and a mesh-wide setting
// naming ${machine:name} gives every machine its mesh name.
func TestTheMachinesNameIsItsSetting(t *testing.T) {
	cat := map[string]Manifest{"hostname": catalogueManifest(t, "hostname")}
	got, err := Resolve(cat, []string{"hostname"}, Node{Name: "ace", At: "ace.internal"}, World{})
	if err != nil {
		t.Fatal(err)
	}
	machines := map[string]string{"ace.internal": "10.42.0.2"}
	nameOf := func(settings SettingsBy) (string, string) {
		t.Helper()
		composed, err := got.Compose(Rendering{Names: machines, Machines: machines, Suffix: "internal",
			Settings: settings})
		if err != nil {
			t.Fatal(err)
		}
		if why := composed.LeftOut["hostname"]; why != "" {
			return "", why
		}
		for _, r := range composed.Resources {
			if r["path"] == "/etc/hostname" {
				return r["content"].(string), ""
			}
		}
		t.Fatal("no /etc/hostname composed")
		return "", ""
	}

	if _, why := nameOf(nil); !strings.Contains(why, "hostname") {
		t.Errorf("with no setting the machine's name was written, or left out for another reason: %q", why)
	}
	if name, why := nameOf(SettingsBy{"hostname": {{From: "ace", Values: map[string]any{"hostname": "Ace"}}}}); name != "Ace\n" {
		t.Errorf("the operator's name for the machine gave %q (%s)", name, why)
	}
	mesh := Layer{From: "the mesh", Values: map[string]any{"hostname": "${machine:name}"}}
	if name, why := nameOf(SettingsBy{"hostname": {mesh}}); name != "ace\n" {
		t.Errorf("a mesh-wide ${machine:name} gave %q (%s)", name, why)
	}
	node := Layer{From: "ace", Values: map[string]any{"hostname": "Ace"}}
	if name, why := nameOf(SettingsBy{"hostname": {mesh, node}}); name != "Ace\n" {
		t.Errorf("a machine's own name over the mesh-wide one gave %q (%s)", name, why)
	}
}