Exec

Source: src/Command/Exec.ts

An Exec runs a shell command purely for its side effects — it has no output contract. Unlike Build, it does not produce or track an output asset; reconcile runs the command and the resource succeeds as long as the command exits with code 0 (a non-zero exit fails with a CommandError).

Use it for one-off setup steps — running migrations, seeding data, code generation, or any command whose result lives outside Alchemy’s state. By default the input files are content-hashed so the command only re-runs when its inputs (or command/cwd/env) change; set memo: false to re-run on every deploy.

Running a Command

yield* Exec("codegen", {
  command: "npm run codegen",
  cwd: "./packages/api",
});

Running with Custom Environment

yield* Exec("migrate", {
  command: "npm run db:migrate",
  env: {
    DATABASE_URL: Redacted.make("postgres://..."),
  },
});

Memoizing Re-Runs

yield* Exec("codegen", {
  command: "npm run codegen",
  memo: { include: ["schema/**"] },
});