Deploy your indexer

A consume() loop is a long-running process with a database and a checkpoint. Here's where to put it.

Four files, whatever the target:

Runnable original: sales-index. The loop itself lives in Index.

Everything above the last row reads from hosted Secondlayer. The last row replaces it.

Delivery is at-least-once. A process killed between the read and the commit re-reads that page on restart, so every write needs a conflict rule:

.onConflict((oc) => oc.column("tx_id").doNothing())

Rows and checkpoint commit in one transaction. With both, a kill mid-batch costs a repeated page — never a gap, never a double count.

Railway, Render, and Fly mark a service unhealthy unless something answers over HTTP. A bare loop binds nothing and gets restarted forever.

onBatch receives progress on its context, so liveness needs no bookkeeping of its own:

let last = { at: 0, ctx: null as ConsumerBatchContext | null };

// in onBatch, before any early return — an empty page still proves it's alive
last = { at: Date.now(), ctx };

Bun.serve({
  port: Number(process.env.PORT ?? 8080),
  fetch: () =>
    Response.json({
      ok: Date.now() - last.at < 120_000,
      last_delivered_height: last.ctx?.height ?? null,
      blocks_behind: last.ctx?.blocksBehind ?? null,
    }),
});

Gate on freshness, not lag: a genesis backfill sits millions of blocks behind the tip and is perfectly healthy. A wedged loop stops reporting pages — that's the restartable signal. ctx.height holds across empty pages and rolls back on a reorg, so it never needs reconstructing from the rows.

Every redeploy arrives as SIGTERM. Pass an AbortSignal and consume() checks it at the top of the loop, never mid-batch, so the in-flight transaction always commits.

const shutdown = new AbortController();
process.on("SIGTERM", () => shutdown.abort());

await index.contractCalls.consume({
  signal: shutdown.signal,
  // …
});

DATABASE_URL is the whole contract — Secondlayer never sees your rows. Any Postgres works; the platform guides each name a local option.