The mesh knows which host runs a machine, and says who is behind another

novox/hq 04-ISSUES/087. A host refuses a declaration carrying a field it does not know, and refuses it WHOLE — deliberately, because that keeps a half-understood declaration off a machine. It makes every new declaration field a flag day: hosts first, then the controller. The mesh had no record of which host any machine ran, so that order was kept by somebody remembering it, and a machine that refused for this reason reported a failure with nothing saying why. The machine has reported its host version since ADR 0141. The controller's own copy of the report did not have the field, so it was unmarshalled into nothing and thrown away on arrival. It has it now, records it, and shows it in `node show` — "not reported" rather than blank, because a machine that has not said is not a machine running nothing. Status says which machines run an older host than another machine does, and which is newest. Deliberately disagreement rather than staleness: nothing delivers a host version yet (ADR 0141, accepted and not built), so the mesh holds no canonical current version and cannot honestly say a machine is behind THE host. What it can say is that the oldest host in the mesh is what the mesh may send. A machine that has reported nothing is left out rather than called behind. Versions compare as strings, which suits the timestamps and commits this mesh uses and is wrong for a scheme where "10" sorts before "9" — said in the code, at the place that would have to learn.
2026-09-30 08:53:59 +02:00
parent bfd983e3f8
commit 7683ba8b5b
7 changed files with 227 additions and 2 deletions
@@ -0,0 +1,98 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/novox/mesh-controller/internal/inventory"
+)
+
+// A host refuses a declaration carrying a field it does not know, and refuses it whole — so every new
+// field is a flag day, and the mesh had no record of which host any machine ran (novox/hq
+// 04-ISSUES/087). The order was kept by somebody remembering it.
+
+func TestTheMeshNamesEveryMachineOnAnOlderHostThanAnother(t *testing.T) {
+	older, newest := hostsBehind([]inventory.Node{
+		{Name: "anchor", HostVersion: "2026-09-29-0918"},
+		{Name: "laptop", HostVersion: "2026-09-29-0113"},
+		{Name: "spare", HostVersion: "2026-09-29-0918"},
+	})
+	if newest != "2026-09-29-0918" {
+		t.Fatalf("the newest reported host is %q", newest)
+	}
+	if len(older) != 1 || older[0].Name != "laptop" {
+		t.Fatalf("the machines behind another are %v, wanted laptop alone", older)
+	}
+}
+
+func TestAMachineThatHasNotSaidIsNotCalledBehind(t *testing.T) {
+	// It may be running anything. Guessing either way is worse than saying it has not said, which
+	// `node show` does per machine.
+	older, newest := hostsBehind([]inventory.Node{
+		{Name: "anchor", HostVersion: "2026-09-29-0918"},
+		{Name: "quiet"},
+	})
+	if newest != "2026-09-29-0918" {
+		t.Fatalf("the newest reported host is %q", newest)
+	}
+	for _, n := range older {
+		if n.Name == "quiet" {
+			t.Fatal("a machine that reported no host version was called behind")
+		}
+	}
+}
+
+func TestAMeshWhereNothingReportedAHostStatesNoDisagreement(t *testing.T) {
+	// Every machine predating ADR 0141, or a mesh that has heard nothing since the column existed.
+	// Saying "0 machines behind" would be a claim the mesh cannot make.
+	older, newest := hostsBehind([]inventory.Node{{Name: "anchor"}, {Name: "laptop"}})
+	if len(older) != 0 || newest != "" {
+		t.Fatalf("a mesh that has been told no host version reported %v / %q", older, newest)
+	}
+}
+
+func TestMachinesAllOnOneHostAreNotBehind(t *testing.T) {
+	older, _ := hostsBehind([]inventory.Node{
+		{Name: "anchor", HostVersion: "v2"},
+		{Name: "laptop", HostVersion: "v2"},
+	})
+	if len(older) != 0 {
+		t.Fatalf("machines agreeing on their host were reported as behind: %v", older)
+	}
+}
+
+func TestAReportedHostVersionIsKeptAndReadBack(t *testing.T) {
+	// The machine has sent this since ADR 0141 and the controller's own copy of the report did not
+	// have the field, so it was unmarshalled into nothing. End to end through the store, because the
+	// fault was a field that existed on one side of the wire only.
+	open := aMesh(t)
+	record, err := open.inventory.NodeByName(t.Context(), "anchor")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if record.HostVersion != "" {
+		t.Fatalf("a machine that never reported one has host version %q", record.HostVersion)
+	}
+	if err := open.inventory.RecordHostVersion(t.Context(), record.ID, "2026-09-30-0214"); err != nil {
+		t.Fatal(err)
+	}
+	again, err := open.inventory.NodeByName(t.Context(), "anchor")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if again.HostVersion != "2026-09-30-0214" {
+		t.Fatalf("the reported host version read back as %q", again.HostVersion)
+	}
+	// An empty report never clears what a machine last said: a bare word that the node is there
+	// says nothing about its host.
+	if err := open.inventory.RecordHostVersion(t.Context(), record.ID, "  "); err != nil {
+		t.Fatal(err)
+	}
+	kept, err := open.inventory.NodeByName(t.Context(), "anchor")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if kept.HostVersion != "2026-09-30-0214" {
+		t.Fatalf("a report carrying no host version cleared what the machine had said: %q",
+			kept.HostVersion)
+	}
+}
@@ -436,6 +436,12 @@ func showNode(ctx context.Context, inv *inventory.Inventory, name string) error
 	}
 	fmt.Printf("%s\n", node.Name)
 	fmt.Printf("  last heard from   %s\n", heardFrom(node))
+	// Which host runs it, as it reported (novox/hq 04-ISSUES/087). Said whenever known, because a
+	// host refuses a declaration carrying a field it does not understand and refuses it WHOLE — so
+	// which host a machine runs is what decides whether the mesh can send it anything new, and
+	// nothing could say it. "not reported" rather than blank: a machine that has not said is a
+	// different thing from one running nothing.
+	fmt.Printf("  host              %s\n", orNotReported(node.HostVersion))
 	if err := showMode(ctx, inv, node); err != nil {
 		return err
 	}
@@ -486,3 +492,11 @@ func showNode(ctx context.Context, inv *inventory.Inventory, name string) error
 	}
 	return nil
 }
+
+// orNotReported is a fact a machine states about itself, or the fact that it has not.
+func orNotReported(s string) string {
+	if strings.TrimSpace(s) == "" {
+		return "not reported — this machine has not said since the mesh began keeping it"
+	}
+	return s
+}
@@ -171,6 +171,25 @@ func statusCommand(ctx context.Context, args []string) error {
 		fmt.Printf("\n  `push --behind` sends them\n\n")
 	}

+	if older, newest := hostsBehind(nodes); len(older) > 0 {
+		// **Before a declaration gains a field, every machine has to understand it** (novox/hq
+		// 04-ISSUES/087). A host refuses a declaration carrying a field it does not know, and refuses
+		// it whole, so every new field is a flag day: hosts first, then the controller. The mesh had
+		// no record of which host any machine ran, so that order was kept by somebody remembering it,
+		// and a machine that refused for this reason reported a failure with nothing saying why.
+		//
+		// Said as disagreement rather than as "out of date", because nothing delivers a host version
+		// yet (ADR 0141, not built) and so the mesh has no canonical current one. What it can say
+		// truthfully is that these machines do not all run the same host, and which is newest of the
+		// ones it has been told about.
+		fmt.Printf("%d machine(s) run an older host than another machine does:\n", len(older))
+		for _, n := range older {
+			fmt.Printf("  %-12s %s\n", n.Name, orNotReported(n.HostVersion))
+		}
+		fmt.Printf("\n  the newest any machine reports is %s. A host refuses a declaration carrying a\n"+
+			"  field it does not know, whole — so a new field reaches these machines last\n\n", newest)
+	}
+
 	if len(asked.untaken) > 0 {
 		// **Before the adopted line, and it breaks "all well".** An adopted machine is a state
 		// somebody chose and can leave alone; a module assigned to one and never taken is work
@@ -369,3 +388,40 @@ func (a answers) well() bool {
 	return len(a.wrong) == 0 && len(a.quiet) == 0 && len(a.behind) == 0 &&
 		len(a.waiting) == 0 && len(a.refused) == 0 && a.network == "" && len(a.untaken) == 0
 }
+
+// hostsBehind is every machine reporting an older host than the newest any machine reports, and that
+// newest version.
+//
+// **Disagreement, not staleness.** Nothing delivers a host version yet
+// ([ADR 0141](../../02-DECISIONS/0141-the-host-delivers-its-own-successor.md) is accepted and not
+// built), so the mesh holds no canonical current version and cannot say a machine is behind THE host.
+// It can say these machines are behind ANOTHER MACHINE's, which is the fact that matters before a
+// declaration gains a field: the oldest host in the mesh is what the mesh may send
+// (novox/hq 04-ISSUES/087).
+//
+// A machine that has not reported a version is left out rather than called behind. It may be running
+// anything, and guessing in either direction is worse than saying it has not said — which `node show`
+// does say, per machine.
+//
+// Versions are compared as strings, which is enough for the timestamps and commits this mesh uses and
+// is wrong for a scheme where "10" sorts before "9". Saying so here rather than pretending: when a
+// version becomes something ordered, this is the place that has to learn how.
+func hostsBehind(nodes []inventory.Node) ([]inventory.Node, string) {
+	newest := ""
+	for _, n := range nodes {
+		if n.HostVersion > newest {
+			newest = n.HostVersion
+		}
+	}
+	if newest == "" {
+		return nil, "" // nothing has reported one; there is no disagreement to state
+	}
+	var older []inventory.Node
+	for _, n := range nodes {
+		if n.HostVersion != "" && n.HostVersion != newest {
+			older = append(older, n)
+		}
+	}
+	sort.Slice(older, func(i, j int) bool { return older[i].Name < older[j].Name })
+	return older, newest
+}