TLS-5, TLS-6: the tool runner holds the indexer's manifests and modules and the assigner's placement and seat-holders from their first views and views events, never their state, and the console gains mesh_first_views and mesh_first_view_again (ADR 0615, ADR 0621, issue 1966)

Claude-Session: https://claude.ai/code/session_01JG73KJNrH5EgFXMKKYSrig
2026-11-04 12:06:20 +01:00
parent 8b1ab467a9
commit 31247dff6b
17 changed files with 577 additions and 64 deletions
@@ -0,0 +1,195 @@
+// Package firstview is the tool runner's picture of the four states it reads of the indexer and the assigner: the assigner's
+// placement and seat-holders, the indexer's manifests and modules (novox/hq ADR 0615 §1, §3; ADR 0621 §2; issue 1966 TLS-5).
+//
+// **It never reads the owners' state.** At start it asks each owner's first-view tool until answered (the owner answers in a
+// runtime of its own, never through this one: ADR 0621 §1), then follows the owner's views family, one event per changed key;
+// a gap in the revisions, or an owner whose state was made again, asks the first view once more, said in the log. Past two
+// minutes without an answer it writes a finding in its own state `findings`, which the condition keeper raises and clears.
+package firstview
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"sort"
+	"sync"
+	"time"
+
+	"git.novox.be/novox/mesh-delivery/sdk/views"
+
+	"github.com/novox/mesh-tools/node-tools/internal/bus"
+)
+
+// The owners and their first-view tools (the tools' addresses are `<owner>.<tool>`).
+const (
+	Indexer  = "mesh-delivery-indexer"
+	Assigner = "mesh-delivery-assigner"
+)
+
+// Spec is one first view the runner holds.
+type Spec struct{ Owner, Tool, State string }
+
+// Specs are the four.
+var Specs = []Spec{
+	{Assigner, "placement", "placement"},
+	{Assigner, "seat-holders", "seat-holders"},
+	{Indexer, "manifests", "manifests"},
+	{Indexer, "modules", "modules"},
+}
+
+// Name is the name a state is read by, `<owner>.<state>`: delivery.PlacementRead, delivery.SeatHoldersRead and the indexer's.
+func (s Spec) Name() string { return s.Owner + "." + s.State }
+
+// Views is the four followers.
+type Views struct {
+	logf      func(string, ...any)
+	followers map[string]*views.Follower // by Spec.Name()
+	byState   map[string]*views.Follower // by the state an event names
+	ctx       context.Context
+	cancel    context.CancelFunc
+	wg        sync.WaitGroup
+	deps      Deps
+}
+
+// FindingsState is the runner's own state the findings are written in.
+const FindingsState = "findings"
+
+// Deps is what the views reach the bus through: Start makes them from the runner's connection, a test from fakes.
+type Deps struct {
+	// Module is the runner's own name, the observer of its findings.
+	Module string
+	// Ask calls an owner's tool, `<owner>.<tool>`.
+	Ask func(address string, body any) (json.RawMessage, error)
+	// Consume hands each event of the owners' views families to deliver, until the stop is called.
+	Consume func(deliver func(bus.Envelope) error) (stop func(), err error)
+	// PutFinding and DeleteFinding keep and remove a finding in the runner's own state.
+	PutFinding    func(key string, value json.RawMessage) error
+	DeleteFinding func(key string) error
+	// Bound and Wait are the follower's (zero: two minutes, five seconds).
+	Bound, Wait time.Duration
+}
+
+// Start asks the four first views, each until answered, and follows the owners' views families on the runner's own
+// consumers. It returns at once: the picture fills as the owners answer.
+func Start(parent context.Context, conn *bus.Conn, logf func(string, ...any)) (*Views, func()) {
+	me := conn.Module()
+	return StartWith(parent, Deps{Module: me,
+		Ask: func(address string, body any) (json.RawMessage, error) {
+			got, err := conn.Ask(address, body, "")
+			return got.Result, err
+		},
+		Consume: func(deliver func(bus.Envelope) error) (func(), error) { return conn.ConsumeAs(me, deliver) },
+		PutFinding: func(key string, value json.RawMessage) error {
+			_, err := conn.StatePut(me, FindingsState, key, value)
+			return err
+		},
+		DeleteFinding: func(key string) error { return conn.StateDelete(me, FindingsState, key) },
+	}, logf)
+}
+
+// StartWith is Start over deps.
+func StartWith(parent context.Context, d Deps, logf func(string, ...any)) (*Views, func()) {
+	ctx, cancel := context.WithCancel(parent)
+	v := &Views{logf: logf, ctx: ctx, cancel: cancel, followers: map[string]*views.Follower{}, byState: map[string]*views.Follower{}, deps: d}
+	for _, s := range Specs {
+		s := s
+		call := func(tool string, body any) (json.RawMessage, error) { return d.Ask(s.Owner+"."+tool, body) }
+		f := &views.Follower{Owner: s.Owner, Tool: s.Tool, State: s.State, Ask: views.AskVia(call, s.Tool), Logf: logf,
+			Bound: d.Bound, Wait: d.Wait,
+			Raise: func(st views.Status) { v.finding(st, true) },
+			Clear: func(st views.Status) { v.finding(st, false) }}
+		v.followers[s.Name()] = f
+		v.byState[s.State] = f
+		v.wg.Add(1)
+		go func() { defer v.wg.Done(); _ = f.Start(ctx) }()
+	}
+	stop, err := d.Consume(v.hear)
+	if err != nil {
+		logf("[mesh-tools] the owners' views are not followed (%v): the pictures are the first views alone until the runner starts again", err)
+		stop = func() {}
+	}
+	return v, func() { stop(); cancel(); v.wg.Wait() }
+}
+
+// hear applies one views event; a gap asks the first view once more.
+func (v *Views) hear(env bus.Envelope) error {
+	ev, err := views.DecodeEvent(env.Body)
+	if err != nil {
+		return nil // not a views event: nothing to hold, nothing to retry
+	}
+	f := v.byState[ev.State]
+	if f == nil || f.Owner != ev.Owner {
+		return nil
+	}
+	if gap, why := f.Apply(ev); gap {
+		v.logf("[mesh-tools] a gap in %s's %s (%s): its first view %s is asked once more", f.Owner, f.State, why, f.Tool)
+		go func() { _ = f.Again(v.ctx, "a gap: "+why) }()
+	}
+	return nil
+}
+
+// finding writes or removes the runner's finding of a first view unanswered past its bound, in its own state.
+func (v *Views) finding(st views.Status, raised bool) {
+	key, value, err := views.UnansweredFinding(v.deps.Module, st, time.Now())
+	if err != nil {
+		v.logf("[mesh-tools] the finding of the first view %s is not made: %v", st.Tool, err)
+		return
+	}
+	if raised {
+		err = v.deps.PutFinding(key, value)
+	} else {
+		err = v.deps.DeleteFinding(key)
+	}
+	if err != nil {
+		v.logf("[mesh-tools] the finding of the first view %s is not kept: %v", st.Tool, err)
+	}
+}
+
+// State is the picture of the state spec names (`<owner>.<state>`), every current value by key; an error says the owner has
+// not answered yet, so nothing is claimed of it.
+func (v *Views) State(name string) (map[string][]byte, error) {
+	f := v.followers[name]
+	if f == nil {
+		return nil, fmt.Errorf("the tool runner holds no first view of %s", name)
+	}
+	select {
+	case <-f.Ready():
+	default:
+		return nil, fmt.Errorf("%s's first view %s has not been answered yet", f.Owner, f.Tool)
+	}
+	out := map[string][]byte{}
+	for k, raw := range f.Values() {
+		out[k] = raw
+	}
+	return out, nil
+}
+
+// Entry is one value of the picture, nil when the owner holds none.
+func (v *Views) Entry(name, key string) ([]byte, error) {
+	all, err := v.State(name)
+	if err != nil {
+		return nil, err
+	}
+	return all[key], nil
+}
+
+// Status is each first view as it stands, by `<owner>.<state>`, sorted.
+func (v *Views) Status() []views.Status {
+	var out []views.Status
+	for _, f := range v.followers {
+		out = append(out, f.Status())
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Owner+out[i].State < out[j].Owner+out[j].State })
+	return out
+}
+
+// Again asks every first view once more, by hand, for why.
+func (v *Views) Again(ctx context.Context, why string) []error {
+	var errs []error
+	for _, f := range v.followers {
+		if err := f.Again(ctx, why); err != nil {
+			errs = append(errs, err)
+		}
+	}
+	return errs
+}