Files
mesh-delivery/modules/mesh-delivery-sdk/steprun/pull_bus.go
T
jschoubben 3e61b70517 SD5, BG11, BLD10: the build modules' shared code moves into the delivery SDK
All of mesh-build-go's buildstep Go module leaves mesh-catalog for
modules/mesh-delivery-sdk: the step run, fetch and release and the
regenerate-and-compare step as the package steprun, the CPU share as
steprun/buildcpu, the conformance kit as steprun/conformance, the seat
generator as seatgen with cmd/seatgen, and cmd/mesh-pack. The three
build modules and the builder's and checker's tests import the SDK and
keep no copy; the SDK requires nothing of mesh-catalog. Code the build
modules share is the delivery domain's SDK, not one module's package.
It carries the build-module round's two new files of that package
(dropdetected.go 247c422f, storedbuilds.go 904b8aed).

Builds: design 47 G §464, §680, §327, §420, §495

Claude-Session: https://claude.ai/code/session_01NcbgfGKaxw984XyAPfLm4h
2026-11-12 05:18:34 +01:00

104 lines
3.4 KiB
Go

package steprun
import (
"context"
"fmt"
"sync"
"time"
sdkstep "git.novox.be/novox/mesh-delivery/modules/mesh-delivery-sdk/buildstep"
"github.com/nats-io/nats.go/jetstream"
)
// JetStreamAsks is a build seat's workers on the bus: the shared pull consumer of each kind on the seat's stream
// (sdkstep.AskStream, AskWorker), which the broker makes when the seat is declared; a holder only binds them.
type JetStreamAsks struct {
JS jetstream.JetStream
Language string
mu sync.Mutex
cons map[string]jetstream.Consumer
}
func (s *JetStreamAsks) consumer(ctx context.Context, kind string) (jetstream.Consumer, error) {
s.mu.Lock()
defer s.mu.Unlock()
if c, ok := s.cons[kind]; ok {
return c, nil
}
stream, err := sdkstep.AskStream(s.Language)
if err != nil {
return nil, err
}
worker, err := sdkstep.AskWorker(s.Language, kind)
if err != nil {
return nil, err
}
c, err := s.JS.Consumer(ctx, stream, worker)
if err != nil {
return nil, fmt.Errorf("binding the %s worker %s on %s: %w", kind, worker, stream, err)
}
if s.cons == nil {
s.cons = map[string]jetstream.Consumer{}
}
s.cons[kind] = c
return c, nil
}
// Next is AskSource's: a fetch of one with no wait when wait is 0, else one that waits at most wait.
func (s *JetStreamAsks) Next(ctx context.Context, kind string, wait time.Duration) (*Pulled, error) {
c, err := s.consumer(ctx, kind)
if err != nil {
return nil, err
}
var batch jetstream.MessageBatch
if wait <= 0 {
batch, err = c.FetchNoWait(1)
} else {
batch, err = c.Fetch(1, jetstream.FetchMaxWait(wait))
}
if err != nil {
return nil, err
}
select {
case msg, ok := <-batch.Messages():
if !ok {
return nil, batch.Error()
}
var delivered uint64 = 1
if meta, err := msg.Metadata(); err == nil && meta != nil {
delivered = meta.NumDelivered
}
return &Pulled{Data: append([]byte(nil), msg.Data()...), Delivered: delivered,
Ack: msg.Ack, InProgress: msg.InProgress, Nak: msg.Nak, Term: msg.Term,
NakAfter: func(delay time.Duration) error { return msg.NakWithDelay(delay) }}, nil
case <-ctx.Done():
return nil, ctx.Err()
}
}
// DeclareAskWorkers makes language's seat stream and its three workers on a bus with no broker: a test's (the build
// modules' integration tests start one). On the mesh the broker declares them from the seat, as it declares every
// seat's stream (mesh-controller internal/broker SeatStreams); a holder never does.
func DeclareAskWorkers(ctx context.Context, js jetstream.JetStream, language string, ackWait time.Duration) error {
stream, err := sdkstep.AskStream(language)
if err != nil {
return err
}
seat, _ := sdkstep.BuildSeat(language)
if _, err := js.CreateOrUpdateStream(ctx, jetstream.StreamConfig{Name: stream, Subjects: []string{"mesh.seat." + seat + ".accept.>"},
Retention: jetstream.WorkQueuePolicy}); err != nil {
return fmt.Errorf("the stream %s: %w", stream, err)
}
for _, kind := range sdkstep.AskKinds {
worker, _ := sdkstep.AskWorker(language, kind)
subject, _ := sdkstep.AskSubject(language, kind)
// Both forms of the accept subject: main's and the asker's, `<main's>.<asker>` (design 47 G §600).
if _, err := js.CreateOrUpdateConsumer(ctx, stream, jetstream.ConsumerConfig{Durable: worker, FilterSubjects: []string{subject, subject + ".*"},
AckPolicy: jetstream.AckExplicitPolicy, AckWait: ackWait, MaxDeliver: 5}); err != nil {
return fmt.Errorf("the worker %s: %w", worker, err)
}
}
return nil
}