mesh-controller/internal/catalogue/hosts_region_test.go

package catalogue_test

import (
	"reflect"
	"strings"
	"testing"

	"github.com/novox/mesh-controller/internal/catalogue"
	"github.com/novox/mesh-controller/internal/overlay"
)

// novox/hq issue 128, held where the host will see it: the shipped networking module's names,
// through the whole composition, and not only through FactsInto.
//
// Composition prefixes a fact's id with the module that asked for it and passes everything else
// through; a step that dropped `into` on the way would send the region as a whole file, and the
// host would write the machine's hosts file over again with every unit test above still green.

// onTheNetwork stands in for the overlay's generator: the node is part of the private network,
// and what the generator writes is not what is under test here.
type onTheNetwork struct{}

func (onTheNetwork) Resources(string) ([]map[string]any, bool, error) {
	return []map[string]any{{"id": "overlay-config", "type": "file",
		"path": "/etc/wireguard/mesh0.conf", "mode": "0600", "content": "[Interface]\n"}}, true, nil
}

func TestTheHostsRegionArrivesAsTheHostWillReadIt(t *testing.T) {
	shelf := provided(t)
	// A resolver restarting on the names another module put on the machine, and one resource it
	// only runs at start — neither of which composition has any business changing.
	resolver, err := catalogue.ParseManifest([]byte(`{
		"module": "resolver", "version": "1", "requires": ["mesh-addressing"],
		"resources": [
			{"id": "seed", "type": "file", "path": "/etc/resolver/seed", "mode": "0644",
			 "content": "seed\n", "at": "start"},
			{"id": "daemon", "type": "service", "unit": "resolver.service", "state": "running",
			 "restart-on": ["seed", "mesh-wireguard.fact-node-names"]}
		]}`))
	if err != nil {
		t.Fatal(err)
	}
	shelf[resolver.Module] = resolver

	got, err := catalogue.Resolve(shelf, []string{overlay.Domain, "resolver"},
		catalogue.Node{Name: "homer", At: "homer.internal"}, catalogue.World{})
	if err != nil {
		t.Fatal(err)
	}
	names := map[string]string{"homer.internal": "10.42.0.1", "marge.internal": "10.42.0.2"}
	out, err := got.Declaration(catalogue.Rendering{
		Names: names, Machines: names, Suffix: "internal",
		Generators: map[string]catalogue.Generator{overlay.Name: onTheNetwork{}},
	})
	if err != nil {
		t.Fatal(err)
	}
	ids := map[string]map[string]any{}
	for _, r := range out {
		ids[r["id"].(string)] = r
	}

	hosts := ids[overlay.Name+".fact-node-names"]
	if hosts == nil {
		t.Fatalf("no names reached the machine; the declaration has %v", keys(ids))
	}
	if hosts["path"] != "/etc/hosts" || hosts["into"] != "block" {
		t.Fatalf("the hosts file is not written into as a region: %v", hosts)
	}
	content := hosts["content"].(string)
	if !strings.Contains(content, "10.42.0.1\thomer.internal\thomer\t# this machine\n") {
		t.Errorf("the region does not name the machine:\n%s", content)
	}
	for _, floor := range []string{"Generated by the mesh", "localhost", "127.0.1.1"} {
		if strings.Contains(content, floor) {
			t.Errorf("the region carries %q, which is the machine's:\n%s", floor, content)
		}
	}

	// The resolver's reference to it still names a resource the host will be sent.
	daemon := ids["resolver.daemon"]
	if daemon == nil {
		t.Fatalf("the resolver's service was not composed: %v", keys(ids))
	}
	for _, named := range daemon["restart-on"].([]any) {
		if ids[named.(string)] == nil {
			t.Errorf("the resolver restarts on %v, which is nothing the host is sent", named)
		}
	}
	if !reflect.DeepEqual(daemon["restart-on"], []any{"resolver.seed", overlay.Name + ".fact-node-names"}) {
		t.Errorf("restart-on is %v", daemon["restart-on"])
	}

	// And a resource's own `at` passes through as the manifest wrote it.
	if seed := ids["resolver.seed"]; seed == nil || seed["at"] != "start" {
		t.Errorf("a resource's at did not survive composition: %v", seed)
	}
}

func keys(m map[string]map[string]any) []string {
	out := make([]string, 0, len(m))
	for k := range m {
		out = append(out, k)
	}
	return out
}