issue 1840/S3: keep each node's declared packages on the bus, so the pacman verbs can say what a node declares

cmd/mesh-controller/declared_packages_integration_test.go

@@ -0,0 +1,61 @@
+//go:build integration
+
+package main
+
+import (
+	"encoding/json"
+	"testing"
+
+	"git.novox.be/novox/mesh-sdk/go/catalogue"
+	"github.com/novox/mesh-controller/internal/inventory"
+)
+
+// 1840/AC5 (ADR 0507 §5): the source of the declared-packages mirror composes each node and names, for a package two modules
+// declare and one declared absent, the modules that declare it; the same records give the same bytes on a second pass, so
+// the mirror writes nothing; a node with no package has a key that says so.
+func TestTheDeclaredPackagesMirrorNamesWhatEachNodesModulesDeclare(t *testing.T) {
+	open := aMesh(t)
+	ctx := t.Context()
+	register(t, open, catalogue.Manifest{Module: "viewer", Version: "1", Resources: []map[string]any{
+		{"id": "pkg-curl", "type": "package", "package": "curl"},
+		{"id": "pkg-nano", "type": "package", "package": "nano", "absent": true}}})
+	register(t, open, catalogue.Manifest{Module: "fetcher", Version: "1", Resources: []map[string]any{
+		{"id": "pkg-curl", "type": "package", "package": "curl"}}})
+	for _, module := range []string{"viewer", "fetcher"} {
+		if _, err := assign(ctx, open, "anchor", module); err != nil {
+			t.Fatalf("assign anchor %s: %v", module, err)
+		}
+	}
+	source := declaredPackagesMirror(open)
+	first, err := source(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var got inventory.DeclaredPackagesMirrored
+	if err := json.Unmarshal(first["anchor"], &got); err != nil {
+		t.Fatalf("anchor has no value: %v", err)
+	}
+	want := []inventory.PackageDeclared{{Package: "curl", Modules: []string{"fetcher", "viewer"}},
+		{Package: "nano", Modules: []string{"viewer"}, Absent: true}}
+	if len(got.Packages) != len(want) {
+		t.Fatalf("anchor declares %+v, want %+v", got.Packages, want)
+	}
+	for i, p := range want {
+		if g := got.Packages[i]; g.Package != p.Package || g.Absent != p.Absent || len(g.Modules) != len(p.Modules) ||
+			(len(p.Modules) > 0 && g.Modules[0] != p.Modules[0]) {
+			t.Errorf("package %d is %+v, want %+v", i, g, p)
+		}
+	}
+	if string(first["laptop"]) != `{"node":"laptop","packages":[]}` {
+		t.Errorf("a node declaring none is %s", first["laptop"])
+	}
+	second, err := source(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for node, value := range first {
+		if string(second[node]) != string(value) {
+			t.Errorf("the value of %s changed between two passes over the same records:\n%s\n%s", node, value, second[node])
+		}
+	}
+}

cmd/mesh-controller/push.go

@@ -281,7 +281,7 @@ func serve(ctx context.Context) (err error) {
 	// The provisioner's plan of each handed module, as its machine was last sent it (design 57 P6), in the module's
 	// assignment.
 	inv.SetProvisioningPlans(inv.SentProvisioningPlans)
-	go mirroringRecords(ctx, inv, bus.Conn, bus)
+	go mirroringRecords(ctx, open, inv, bus.Conn, bus)
 	// And the bucket of the files that travel by digest, judged against what each machine's latest declaration names (ADR 0486 §3).
 	go sweepingDeclarationFiles(ctx, inv, bus.Conn)
 	// And the key of each plan in its build phase, which holds the build seat's checks while a delivery builds (ADR 0483 clause 2).

cmd/mesh-controller/record_mirrors.go

@@ -7,6 +7,7 @@ import (
 	"sort"
 	"time"
 
+	"git.novox.be/novox/mesh-sdk/go/compose"
 	"github.com/nats-io/nats.go"
 	"github.com/nats-io/nats.go/jetstream"
 
@@ -29,7 +30,7 @@ import (
 const mirrorEvery = 10 * time.Second
 
 // mirroringRecords keeps the mirrors current for as long as this controller serves: ctx ends when it stops.
-func mirroringRecords(ctx context.Context, inv *inventory.Inventory, conn *nats.Conn, announce recordmirror.Announcer) {
+func mirroringRecords(ctx context.Context, open *stores, inv *inventory.Inventory, conn *nats.Conn, announce recordmirror.Announcer) {
 	api, err := jetstream.New(conn)
 	if err != nil {
 		fmt.Printf("the record mirrors are not kept: %v\n", err)
@@ -44,8 +45,9 @@ func mirroringRecords(ctx context.Context, inv *inventory.Inventory, conn *nats.
 		return e
 	}
 	sources := map[string]func(context.Context) (map[string][]byte, error){
-		recordmirror.DeclaredConfig.Name: inv.DeclaredConfigMirror,
-		recordmirror.Predefined.Name:     inv.PredefinedMirror,
+		recordmirror.DeclaredConfig.Name:   inv.DeclaredConfigMirror,
+		recordmirror.Predefined.Name:       inv.PredefinedMirror,
+		recordmirror.DeclaredPackages.Name: declaredPackagesMirror(open),
 	}
 	writers := map[string]*recordmirror.Writer{}
 	failing := map[string]string{}
@@ -176,3 +178,36 @@ func keepingAssignments(ctx context.Context, inv *inventory.Inventory, announce
 	}
 	events.known = now
 }
+
+// declaredPackagesMirror is the source of the declared-packages mirror (ADR 0507 §5): each node's composition, asked as a
+// question that makes nothing, and the packages it declares with the modules that declare them. A node whose own set does
+// not compose has no key, and any other failure to read is the pass's error, so a key is never purged for a store that
+// could not be read.
+func declaredPackagesMirror(open *stores) func(context.Context) (map[string][]byte, error) {
+	return func(ctx context.Context) (map[string][]byte, error) {
+		in, err := inputFor(ctx, open)
+		if err != nil {
+			return nil, err
+		}
+		// Which module owns each resource is carried only for a node-engine that reads it, so every node is asked as one that does.
+		asked := in.Input
+		asked.Nodes = append([]compose.Node(nil), in.Nodes...)
+		for i := range asked.Nodes {
+			asked.Nodes[i].ReadsModules = true
+		}
+		out := map[string][]byte{}
+		for _, n := range in.sortedNodes() {
+			d, _, err := compose.ComposeIn(asked, n.Name, compose.Foreseeing)
+			if compose.IsUnresolvable(err) {
+				continue
+			}
+			if err != nil {
+				return nil, fmt.Errorf("the packages %s declares cannot be read: %w", n.Name, err)
+			}
+			if out[n.Name], err = inventory.DeclaredPackagesValue(n.Name, d.Resources, d.ModuleOf); err != nil {
+				return nil, err
+			}
+		}
+		return out, nil
+	}
+}