Avoid Non-deterministic Code Outside context.run

A workflow endpoint should always produce the same results, even if it’s called multiple times. Avoid:

Non-idempotent functions
Time-dependent code
Randomness

Example of what to avoid:

export const { POST } = serve<{ entryId: string }>(async (context) => {  const { entryId } = context.requestPayload;  // 👇 Problem: Non-idempotent function outside context.run:  const result = await getResultFromDb(entryId);  if (result.return) {    return;  }  // ...})

export const { POST } = serve<string>(async (context) => {  const input = context.requestPayload  // 👇 Problem: time-dependent code  if (Date.now() % 5 == 2) {    await context.run("step-1", () => {      // ...    })  } else {    await context.run("step-2", () => {      // ...    })  }})

export const { POST } = serve<string>(async (context) => {  const input = context.requestPayload  // 👇 Problem: random code  if (Math.floor(Math.random() * 10) % 5 == 2) {    await context.run("step-1", () => {      // ...    })  } else {    await context.run("step-2", () => {      // ...    })  }})

@serve.post("/api/example")async def example(context: AsyncWorkflowContext[str]) -> None:    entry_id = context.request_payload["entry_id"]    # 👇 Problem: Non-idempotent function outside context.run:    result = await get_result_from_db(entry_id)    if result.should_return:        return    # ...

@serve.post("/api/example")async def example(context: AsyncWorkflowContext[str]) -> None:    input = context.request_payload    # 👇 Problem: time-dependent code    if time.time() % 5 == 2:        await context.run("step-1", lambda: ...)    else:        await context.run("step-2", lambda: ...)

@serve.post("/api/example")async def example(context: AsyncWorkflowContext[str]) -> None:    input = context.request_payload    # 👇 Problem: random code    if random.randint(0, 9) % 5 == 2:        await context.run("step-1", lambda: ...)    else:        await context.run("step-2", lambda: ...)

If you implement a non-idempotent code like the one shown above, you might encounter Failed to authenticate Workflow request. errors. This can happen if you return based on the result of the non-idempotent code before any workflow step.

To prevent this, ensure that the non-idempotent code (such as getResultFromDb in the example) runs within context.run.

const result = await context.run("get-result-from-db", async () => {  return await getResultFromDb(entryId)});if (result.return) {  return;}

async def _get_result_from_db():    return await get_result_from_db(entry_id)result = await context.run("get-result-from-db", _get_result_from_db)if result.should_return:    return