mesh-delivery/modules/mesh-delivery-builder/cmd/mesh-delivery-builder/versions.go

package main

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"strings"
	"time"

	"github.com/nats-io/nats.go"
	"github.com/nats-io/nats.go/jetstream"

	"git.novox.be/novox/mesh-sdk/go/delivery"
	"git.novox.be/novox/mesh-sdk/go/health"
	"git.novox.be/novox/mesh-sdk/go/process"

	"mesh-delivery-builder/internal/build"
	"mesh-delivery-builder/internal/versions"
)

// The floor's two module tools (novox/hq design 51 *The floor*); the seat's is `seat:<registry>.versions`.
const (
	bridgeTagsTool   = "mesh-delivery-forge-bridge.bridge_tags"
	requirementsTool = "mesh-delivery-indexer.indexer_requirements"
)

// awaitedVersions is the state versions as versions.Store: bound once the bus holds it (the grants part makes it, issue
// 1790); until then every use is an error, so a trunk build is built unnumbered and said (build.Builder.number).
type awaitedVersions struct{ b *process.AwaitedBucket }

var errVersionsMissing = errors.New("the state " + versions.Bucket + " is not on the bus yet")

func (s awaitedVersions) kv() (jetstream.KeyValue, error) {
	if kv := s.b.KV(); kv != nil {
		return kv, nil
	}
	return nil, errVersionsMissing
}

func (s awaitedVersions) Get(ctx context.Context, key string) ([]byte, uint64, bool, error) {
	kv, err := s.kv()
	if err != nil {
		return nil, 0, false, err
	}
	e, err := kv.Get(ctx, key)
	if errors.Is(err, jetstream.ErrKeyNotFound) {
		return nil, 0, false, nil
	}
	if err != nil {
		return nil, 0, false, err
	}
	return e.Value(), e.Revision(), true, nil
}

func versionsConflict(err error) error {
	if errors.Is(err, jetstream.ErrKeyExists) || errors.Is(err, jetstream.ErrKeyRevisionMismatch) {
		return versions.ErrConflict
	}
	return err
}

func (s awaitedVersions) Create(ctx context.Context, key string, value []byte) (uint64, error) {
	kv, err := s.kv()
	if err != nil {
		return 0, err
	}
	rev, err := kv.Create(ctx, key, value)
	return rev, versionsConflict(err)
}

func (s awaitedVersions) Update(ctx context.Context, key string, value []byte, revision uint64) (uint64, error) {
	kv, err := s.kv()
	if err != nil {
		return 0, err
	}
	rev, err := kv.Update(ctx, key, value, revision)
	return rev, versionsConflict(err)
}

func (s awaitedVersions) KeysOf(ctx context.Context, filter string) ([]string, error) {
	kv, err := s.kv()
	if err != nil {
		return nil, err
	}
	l, err := kv.ListKeysFiltered(ctx, filter)
	if err != nil {
		return nil, err
	}
	defer func() { _ = l.Stop() }()
	var out []string
	for k := range l.Keys() {
		out = append(out, k)
	}
	return out, nil
}

// floorVia is the floor's three sources as calls of the builder's own account (design 51 *The floor*): the seat's verb
// versions, the forge bridge's bridge_tags and the indexer's indexer_requirements. A call that fails is that source
// silent.
func floorVia(call toolCaller) versions.FloorSources {
	return versions.FloorSources{
		Seat: func(_ context.Context, seat, name string) ([]string, error) {
			raw, err := call("seat:"+seat+".versions", map[string]any{"name": name})
			if err != nil {
				return nil, err
			}
			var a struct {
				Versions []struct {
					Version string `json:"version"`
				} `json:"versions"`
			}
			if err := json.Unmarshal(raw, &a); err != nil {
				return nil, fmt.Errorf("%s's versions answered what is no list of versions: %w", seat, err)
			}
			var out []string
			for _, v := range a.Versions {
				if v.Version != "" {
					out = append(out, v.Version)
				}
			}
			return out, nil
		},
		Tags: func(_ context.Context, repository, prefix string) ([]string, error) {
			raw, err := call(bridgeTagsTool, map[string]any{"repository": repository, "prefix": prefix})
			if err != nil {
				return nil, err
			}
			var a struct {
				Tags []string `json:"tags"`
			}
			if err := json.Unmarshal(raw, &a); err != nil {
				return nil, fmt.Errorf("bridge_tags answered what is no list of tags: %w", err)
			}
			return a.Tags, nil
		},
		Requirements: func(_ context.Context, name string) ([]string, error) {
			raw, err := call(requirementsTool, map[string]any{"package": name})
			if err != nil {
				return nil, err
			}
			var a struct {
				Requirements []string `json:"requirements"`
			}
			if err := json.Unmarshal(raw, &a); err != nil {
				return nil, fmt.Errorf("indexer_requirements answered what is no list of versions: %w", err)
			}
			return a.Requirements, nil
		},
	}
}

// emitNumbered says the builder's event version.numbered (design 51 *Events of the builder*), on its own family apart
// from its builds' ends; the name and version are the bus's dedup id.
func emitNumbered(ctx context.Context, js jetstream.JetStream, cred process.Account, b versions.NumberedBody) error {
	id := "numbered-" + versions.Key(b.Name, b.Version)
	if b.Again != "" {
		id += "-again-" + b.Again
	}
	if err := emitEvent(ctx, js, cred, versions.NumberedEvent, id, b); err != nil {
		return fmt.Errorf("saying %s for %s@%s: %w", versions.NumberedEvent, b.Name, b.Version, err)
	}
	return nil
}

// emitEvent says one of the builder's events, mesh.mod.<module>.event.<event>, with the SDK's envelope headers and id as
// the bus's dedup id.
func emitEvent(ctx context.Context, js jetstream.JetStream, cred process.Account, event, id string, body any) error {
	data, err := json.Marshal(body)
	if err != nil {
		return err
	}
	msg := nats.NewMsg(cred.EventSubject(event))
	msg.Header.Set("x-event-id", id)
	msg.Header.Set("x-source", cred.Module)
	msg.Header.Set("x-node", cred.Node)
	msg.Header.Set("x-time", time.Now().UTC().Format(time.RFC3339Nano))
	msg.Header.Set("content-type", "application/json")
	msg.Data = data
	pub, cancel := context.WithTimeout(ctx, 10*time.Second)
	defer cancel()
	_, err = js.PublishMsg(pub, msg, jetstream.WithMsgID(id))
	return err
}

// The events on the builder's consumer of EVENTS that wake a floor (design 51 *The floor*, DLV-B3b).
var (
	manifestAcceptedSubject = "mesh.mod." + delivery.IndexerModule + ".event." + delivery.ManifestAcceptedEvent
	conditionClearedSubject = "mesh.mod." + health.KeeperModule + ".event." + health.EventCleared
)

// floorWake asks the floor of the names an event wakes again, by looking at every module again: a trunk build is
// numbered before its claim (build.Builder.number).
type floorWake struct {
	b     *build.Builder
	waits *versions.FloorWaits
	logf  func(string, ...any)
}

// heard takes a message of the consumer in when it is one that wakes a floor, acknowledged, and answers whether it was.
func (f *floorWake) heard(ctx context.Context, m jetstream.Msg) bool {
	switch m.Subject() {
	case manifestAcceptedSubject:
		f.ack(m)
		f.wake(ctx, versions.WakeAccepted, "", "")
	case conditionClearedSubject:
		f.ack(m)
		var e health.Event
		if err := json.Unmarshal(m.Data(), &e); err != nil {
			f.logf("%s holds what is no condition, left: %v", m.Subject(), err)
			return true
		}
		for _, module := range conditionModules(e.Subject.ID) {
			f.wake(ctx, versions.WakeCleared, "", module)
		}
	default:
		return false
	}
	return true
}

func (f *floorWake) ack(m jetstream.Msg) {
	if err := m.Ack(); err != nil {
		f.logf("acknowledging %s: %v", m.Subject(), err)
	}
}

// wake looks at every module again when the event wakes a name, and says which.
func (f *floorWake) wake(ctx context.Context, kind, seat, module string) {
	names := f.waits.Wake(kind, seat, module, "")
	if len(names) == 0 {
		return
	}
	f.logf("the floor of %s is asked again: %s", strings.Join(names, ", "), kind)
	f.b.Reconsider(ctx)
}

// conditionModules are the tokens of a condition's subject id (`<node>/<module>`, `<module>.<check>`): a module named
// among them is the one whose condition cleared.
func conditionModules(id string) []string {
	return strings.FieldsFunc(id, func(r rune) bool { return r == '/' || r == '.' || r == ':' })
}

// doneVia says whether a build key is done, read from the builder's own builds state: the build's file is held.
func doneVia(b *build.Builder) func(ctx context.Context, module, fp string) (bool, error) {
	return func(ctx context.Context, module, fp string) (bool, error) {
		key, err := delivery.BuilderBuildKey(module, fp)
		if err != nil {
			return false, err
		}
		raw, _, found, err := b.Claimer.Store.Get(ctx, key)
		if err != nil || !found {
			return false, err
		}
		cur, err := delivery.DecodeBuilderBuild(raw)
		if err != nil {
			return false, err
		}
		return cur.State == delivery.BuildDone, nil
	}
}

// removeVia calls a registry seat's remove for one tagged version, as the builder's own account (design 51 *Tagged
// versions*): the reason tag-gone; the seat says removed on its events.
func removeVia(call toolCaller) func(ctx context.Context, seat string, e versions.Entry) error {
	return func(_ context.Context, seat string, e versions.Entry) error {
		_, err := call("seat:"+seat+".remove", map[string]any{"name": e.Name, "version": e.Version, "tag": e.Tag, "reason": "tag-gone"})
		return err
	}
}

// tagAsked answers an unanswered value of tag-asks by compare-and-set at its revision, said in the log.
func tagAsked(ctx context.Context, acts versions.Acts, kv jetstream.KeyValue, e jetstream.KeyValueEntry, logf func(string, ...any)) {
	if e.Operation() != jetstream.KeyValuePut {
		return
	}
	t, err := versions.DecodeTagAsk(e.Value())
	if err != nil {
		logf("%s.%s holds what is not a tag ask, left: %v", versions.TagAsksState, e.Key(), err)
		return
	}
	if !t.Answered.IsZero() {
		return
	}
	t = acts.TagAsked(ctx, t, time.Now())
	logf("%s: %s of %s %s by %s (%s): %s", e.Key(), map[bool]string{true: "untag", false: "tag ask"}[t.Untag], t.Repository, t.Branch, t.By, t.Why, t.Answer)
	data, err := json.Marshal(t)
	if err != nil {
		return
	}
	if _, err := kv.Update(ctx, e.Key(), data, e.Revision()); err != nil && !errors.Is(err, jetstream.ErrKeyExists) && !errors.Is(err, jetstream.ErrKeyRevisionMismatch) {
		logf("%s.%s: the answer could not be written: %v", versions.TagAsksState, e.Key(), err)
	}
}