Carry an adopted node's mode and taken modules in every declaration, from one marshaller (hq ADR 0100)

cmd/mesh-controller/sendable.go

@@ -0,0 +1,96 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"sort"
+
+	"github.com/novox/mesh-controller/internal/catalogue"
+	"github.com/novox/mesh-controller/internal/inventory"
+)
+
+// sendable is a declaration as a machine is sent it: its resources and, for an adopted node, its
+// mode and which modules were taken on it (novox/hq ADR 0100).
+//
+// **Body is the only place the envelope is marshalled.** It was written by hand at every send site,
+// in the digest the mesh compares, and in `plan --json`; a key added at one and not another would
+// make a machine look out of date for ever, or send something `plan` never showed.
+type sendable struct {
+	Resources []map[string]any
+	// Adoption is nil for a converged node, and then the body is byte for byte what it was before
+	// adoption existed: an older host parses the envelope strictly and would refuse the key.
+	Adoption *adoptionEnvelope
+}
+
+// adoptionEnvelope is what an adopted node is told about its mode. Taken is every module taken on
+// it that it runs; Untaken is, for every module it runs that is not taken, the ids of that module's
+// files and containers — the resources the host keeps as found until the module is taken. Ids
+// rather than a rule to split them by, because a module's name may contain a dot.
+type adoptionEnvelope struct {
+	Taken   []string            `json:"taken"`
+	Untaken map[string][]string `json:"untaken,omitempty"`
+}
+
+// Body is the declaration's bytes, as sent and as digested.
+func (s sendable) Body() ([]byte, error) {
+	envelope := map[string]any{"declaration": 1, "resources": s.Resources}
+	if s.Adoption != nil {
+		envelope["adoption"] = s.Adoption
+	}
+	return json.Marshal(envelope)
+}
+
+// adoptionOf is the envelope for a node, nil when it is converged.
+func adoptionOf(ctx context.Context, inv *inventory.Inventory, node string,
+	plan catalogue.Resolution, composed catalogue.Composed) (*adoptionEnvelope, error) {
+	record, err := inv.NodeByName(ctx, node)
+	if err != nil {
+		return nil, err
+	}
+	if !record.Adopted {
+		return nil, nil
+	}
+	taken, err := inv.Taken(ctx, node)
+	if err != nil {
+		return nil, err
+	}
+	return adoptionFor(plan, taken, composed), nil
+}
+
+// adoptionFor is the envelope computed from what was taken and who owns each resource.
+//
+// Every module the node runs that is not taken is untaken — including one pulled in by another
+// rather than assigned: what is found is kept until its module is taken, whoever put it there.
+func adoptionFor(plan catalogue.Resolution, taken []string,
+	composed catalogue.Composed) *adoptionEnvelope {
+	isTaken := map[string]bool{}
+	for _, m := range taken {
+		isTaken[m] = true
+	}
+	out := &adoptionEnvelope{Taken: []string{}}
+	runs := map[string]bool{}
+	for _, m := range plan.Modules {
+		runs[m.Module] = true
+		if isTaken[m.Module] {
+			out.Taken = append(out.Taken, m.Module)
+		}
+	}
+	sort.Strings(out.Taken)
+	for _, r := range composed.Resources {
+		id, _ := r["id"].(string)
+		module, owned := composed.Owner[id]
+		if !owned || !runs[module] || isTaken[module] {
+			continue
+		}
+		switch r["type"] {
+		case "file", "container":
+		default:
+			continue
+		}
+		if out.Untaken == nil {
+			out.Untaken = map[string][]string{}
+		}
+		out.Untaken[module] = append(out.Untaken[module], id)
+	}
+	return out
+}