sqs

babelqueue-go/sqs

Amazon SQS transport for the BabelQueue Go runtime — "Polyglot Queues, Simplified."

It implements §3 of the broker-bindings contract: the canonical envelope is the message body, and the contract fields are projected onto native SQS MessageAttributes so a PHP/Python/… peer can route and correlate without parsing the body.

Install

go get github.com/babelqueue/babelqueue-go/sqs

Use

ctx := context.Background()

tr, err := sqs.New(ctx,
    sqs.WithRegion("eu-central-1"),
    // sqs.WithEndpoint("http://localhost:4566"), // LocalStack/ElasticMQ
)
if err != nil { log.Fatal(err) }

app := babelqueue.NewApp(tr, babelqueue.WithDefaultQueue("orders"))

// produce
app.Publish(ctx, "urn:babel:orders:created", map[string]any{"order_id": 1042})

// consume
app.Handle("urn:babel:orders:created", func(ctx context.Context, env babelqueue.Envelope) error {
    // env.Data, env.TraceID ...
    return nil
})
app.Run(ctx)

Credentials come from the standard AWS default provider chain (env vars, shared profile, instance role, IRSA, SSO). FIFO queues: add sqs.WithFIFO(true) (the queue name must end in .fifo).

How it maps to the contract (§3)

The envelope is unchanged (schema_version stays 1); SQS is purely additive.

Out-of-band transport headers

This transport implements the optional babelqueue.HeaderPublisher capability: out-of-band headers ride as String MessageAttributes beside the frozen envelope, never in it (GR-1), and are surfaced back to the consumer on ReceivedMessage.Headers. So the optional otel module's W3C traceparent (ADR-0028) — and the bq-replay-bypass marker (ADR-0027) — propagate over SQS for true cross-hop span parent-child linkage. Headers are merged beside the contract bq-* attributes without clobbering them, and bounded by the 10-attribute SQS limit (the contract attributes are always preserved first).

Test

go test ./...                       # unit (fake SQS client, no broker)
go test -tags=integration ./...     # integration (needs LocalStack at SQS_ENDPOINT)

The default unit run fakes the AWS client. The New config-loading path is covered by the LocalStack integration test (-tags=integration).

License

MIT