[V0_FILE]typescriptreact:file="app/components/demo.tsx" "use client"; import { useCallback, useEffect, useMemo, useRef, useState } from "react"; import type { AttemptSnapshot, MockRetrySnapshot, RetryLogEvent, } from "@/app/api/mock/store"; import { RetryCodeWorkbench } from "./retry-code-workbench"; type LifecycleState = "idle" | "running" | "completed" | "failed"; type HighlightTone = "amber" | "cyan" | "green" | "red"; type StartResponse = { runId: string; status: "running" | "completed" | "failed"; snapshot: MockRetrySnapshot; }; type RetryWorkflowLineMap = { attempt: number[]; sleep: number[]; successReturn: number[]; failureReturn: number[]; }; type RetryStepLineMap = { attempt: number[]; successReturn: number[]; }; type RetryBackoffDemoProps = { workflowCode: string; workflowHtmlLines: string[]; workflowLineMap: RetryWorkflowLineMap; stepCode: string; stepHtmlLines: string[]; stepLineMap: RetryStepLineMap; }; const POLL_INTERVAL_MS = 120; const MAX_ATTEMPTS = 5; const BASE_DELAY_MS = 1_000; const DEFAULT_FAIL_FIRST_ATTEMPTS = 2; const FAIL_FIRST_MIN = 0; const FAIL_FIRST_MAX = MAX_ATTEMPTS; const FAIL_FIRST_OPTIONS = Array.from( { length: FAIL_FIRST_MAX - FAIL_FIRST_MIN + 1 }, (_, index) => FAIL_FIRST_MIN + index ); function buildContactId(): string { return `contact_${Date.now().toString(36)}_${Math.random().toString(36).slice(2, 6)}`; } function formatDurationLabel(durationMs: number): string { if (durationMs >= 1000 && durationMs % 1000 === 0) { return `${durationMs / 1000}s`; } return `${durationMs}ms`; } function formatElapsedLabel(durationMs: number): string { const seconds = (durationMs / 1000).toFixed(2); return `${seconds}s`; } async function postJson( url: string, body: Record, signal: AbortSignal ): Promise { const response = await fetch(url, { method: "POST", headers: { "Content-Type": "application/json", }, body: JSON.stringify(body), signal, }); const payload = (await response .json() .catch(() => ({ error: "Failed to parse JSON response" }))) as | T | { error?: string }; if (signal.aborted) { throw new DOMException("Request aborted", "AbortError"); } if (!response.ok) { const message = typeof payload === "object" && payload && "error" in payload ? (payload.error ?? `Request failed (${response.status})`) : `Request failed (${response.status})`; throw new Error(message); } return payload as T; } export function RetryBackoffDemo({ workflowCode, workflowHtmlLines, workflowLineMap, stepCode, stepHtmlLines, stepLineMap, }: RetryBackoffDemoProps) { const [failFirstAttempts, setFailFirstAttempts] = useState( DEFAULT_FAIL_FIRST_ATTEMPTS ); const [lifecycle, setLifecycle] = useState("idle"); const [runId, setRunId] = useState(null); const [snapshot, setSnapshot] = useState(null); const [error, setError] = useState(null); const pollTimerRef = useRef | null>(null); const inFlightRef = useRef(false); const abortRef = useRef(null); const startButtonRef = useRef(null); const stopPolling = useCallback(() => { if (pollTimerRef.current) { clearInterval(pollTimerRef.current); pollTimerRef.current = null; } inFlightRef.current = false; }, []); const ensureAbortController = useCallback((): AbortController => { if (!abortRef.current || abortRef.current.signal.aborted) { abortRef.current = new AbortController(); } return abortRef.current; }, []); useEffect(() => { return () => { stopPolling(); abortRef.current?.abort(); abortRef.current = null; }; }, [stopPolling]); const fetchStatusSnapshot = useCallback(async (targetRunId: string, signal: AbortSignal) => { const response = await fetch( `/api/mock/status?runId=${encodeURIComponent(targetRunId)}`, { cache: "no-store", signal, } ); const payload = (await response .json() .catch(() => ({ error: "Failed to parse status response" }))) as | MockRetrySnapshot | { error?: string }; if (signal.aborted) { throw new DOMException("Request aborted", "AbortError"); } if (!response.ok) { const message = typeof payload === "object" && payload && "error" in payload ? payload.error ?? `Status request failed (${response.status})` : `Status request failed (${response.status})`; throw new Error(message); } return payload as MockRetrySnapshot; }, []); const beginPolling = useCallback( (targetRunId: string) => { stopPolling(); const poll = async () => { if (inFlightRef.current) { return; } inFlightRef.current = true; let signal: AbortSignal | null = null; try { const controller = ensureAbortController(); signal = controller.signal; const nextSnapshot = await fetchStatusSnapshot(targetRunId, signal); if (signal.aborted) { return; } setSnapshot(nextSnapshot); if (nextSnapshot.status === "completed") { if (signal.aborted) { return; } setLifecycle("completed"); stopPolling(); return; } if (nextSnapshot.status === "failed") { if (signal.aborted) { return; } setLifecycle("failed"); stopPolling(); return; } if (signal.aborted) { return; } setLifecycle("running"); } catch (pollError) { if ((signal && signal.aborted) || (pollError instanceof Error && pollError.name === "AbortError")) { return; } stopPolling(); setLifecycle("failed"); const message = pollError instanceof Error ? pollError.message : "Failed to read retry status"; setError(message); } finally { inFlightRef.current = false; } }; void poll(); pollTimerRef.current = setInterval(() => { void poll(); }, POLL_INTERVAL_MS); }, [ensureAbortController, fetchStatusSnapshot, stopPolling] ); const hasScrolledRef = useRef(false); useEffect(() => { if (lifecycle !== "idle" && !hasScrolledRef.current) { hasScrolledRef.current = true; const heading = document.getElementById("try-it-heading"); if (heading) { const top = heading.getBoundingClientRect().top + window.scrollY; window.scrollTo({ top, behavior: "smooth" }); } } if (lifecycle === "idle") { hasScrolledRef.current = false; } }, [lifecycle]); const handleStart = useCallback(async () => { setError(null); stopPolling(); abortRef.current?.abort(); abortRef.current = null; const controller = ensureAbortController(); const signal = controller.signal; try { const payload = await postJson("/api/mock/start", { contactId: buildContactId(), maxAttempts: MAX_ATTEMPTS, failuresBeforeSuccess: failFirstAttempts, baseDelayMs: BASE_DELAY_MS, }, signal); if (signal.aborted) { return; } setRunId(payload.runId); if (signal.aborted) { return; } setSnapshot(payload.snapshot); if (signal.aborted) { return; } setLifecycle(payload.status === "running" ? "running" : payload.status); if (payload.status === "running") { if (signal.aborted) { return; } beginPolling(payload.runId); } } catch (startError) { if (signal.aborted || (startError instanceof Error && startError.name === "AbortError")) { return; } const message = startError instanceof Error ? startError.message : "Failed to start mock retry run"; setError(message); setLifecycle("idle"); } }, [beginPolling, ensureAbortController, failFirstAttempts, stopPolling]); const handleReset = useCallback(() => { stopPolling(); abortRef.current?.abort(); abortRef.current = null; setLifecycle("idle"); setRunId(null); setSnapshot(null); setError(null); setTimeout(() => { startButtonRef.current?.focus(); }, 0); }, [stopPolling]); const isRunning = lifecycle === "running"; const phaseExplainer = useMemo(() => { if (!snapshot) { return "Waiting to start a run."; } if (snapshot.status === "running" && snapshot.currentPhase.phase === "attempt") { return `Attempt ${snapshot.currentPhase.attempt} is executing fetchCrmContact() in a step.`; } if (snapshot.status === "running" && snapshot.currentPhase.phase === "sleep") { return `sleep('${formatDurationLabel(snapshot.currentPhase.nextDelayMs ?? 0)}') in progress. The workflow is durably suspended and consuming zero compute.`; } if (snapshot.status === "completed") { return `Run completed on attempt ${snapshot.result?.attempt}.`; } if (snapshot.status === "failed") { return `Run failed after attempt ${snapshot.result?.attempt}. Max attempts exhausted.`; } return "Run is active."; }, [snapshot]); type GutterMarkKind = "success" | "fail"; const codeState = useMemo(() => { const wfMarks: Record = {}; const stepMarks: Record = {}; if (snapshot) { // Find indices of last fail and last attempt to determine visibility const lastSuccess = [...snapshot.executionLog].reverse().find((e) => e.kind === "success"); let lastFailIdx = -1; let lastAttemptIdx = -1; for (let i = snapshot.executionLog.length - 1; i >= 0; i--) { if (lastFailIdx === -1 && snapshot.executionLog[i].kind === "fail") lastFailIdx = i; if (lastAttemptIdx === -1 && snapshot.executionLog[i].kind === "attempt") lastAttemptIdx = i; if (lastFailIdx !== -1 && lastAttemptIdx !== -1) break; } if (lastSuccess) { for (const ln of workflowLineMap.attempt) wfMarks[ln] = "success"; for (const ln of stepLineMap.attempt) stepMarks[ln] = "success"; } else if (lastFailIdx > lastAttemptIdx) { // Show red X from fail until the next attempt starts (code highlights again) for (const ln of workflowLineMap.attempt) wfMarks[ln] = "fail"; for (const ln of stepLineMap.attempt) stepMarks[ln] = "fail"; } const hasSlept = snapshot.executionLog.some( (e) => e.kind === "sleep" || e.kind === "wakeup" ); if (hasSlept) { for (const ln of workflowLineMap.sleep) wfMarks[ln] = "success"; } if (snapshot.status === "completed") { for (const ln of workflowLineMap.successReturn) wfMarks[ln] = "success"; for (const ln of stepLineMap.successReturn) stepMarks[ln] = "success"; } if (snapshot.status === "failed") { for (const ln of workflowLineMap.failureReturn) wfMarks[ln] = "fail"; } } if (!snapshot) { return { tone: "amber" as HighlightTone, workflowActiveLines: [] as number[], stepActiveLines: [] as number[], workflowGutterMarks: wfMarks, stepGutterMarks: stepMarks, }; } if (snapshot.status === "running" && snapshot.currentPhase.phase === "attempt") { return { tone: "amber" as HighlightTone, workflowActiveLines: workflowLineMap.attempt, stepActiveLines: stepLineMap.attempt, workflowGutterMarks: wfMarks, stepGutterMarks: stepMarks, }; } if (snapshot.status === "running" && snapshot.currentPhase.phase === "sleep") { return { tone: "cyan" as HighlightTone, workflowActiveLines: workflowLineMap.sleep, stepActiveLines: [] as number[], workflowGutterMarks: wfMarks, stepGutterMarks: stepMarks, }; } if (snapshot.status === "completed") { return { tone: "green" as HighlightTone, workflowActiveLines: workflowLineMap.successReturn, stepActiveLines: stepLineMap.successReturn, workflowGutterMarks: wfMarks, stepGutterMarks: stepMarks, }; } return { tone: "red" as HighlightTone, workflowActiveLines: workflowLineMap.failureReturn, stepActiveLines: [] as number[], workflowGutterMarks: wfMarks, stepGutterMarks: stepMarks, }; }, [snapshot, stepLineMap, workflowLineMap]); return (

{error && (

{error}

)}

{lifecycle !== "idle" && ( )} Fail first

{phaseExplainer}

{runId && ( run: {runId} )}

sleep() → durable backoff with zero compute between attempts

); } function AttemptLadder({ attempts, currentPhase, }: { attempts: AttemptSnapshot[]; currentPhase: MockRetrySnapshot["currentPhase"]["phase"] | null; }) { if (attempts.length === 0) { return (

No attempts yet.

); } return (

{attempts.map((attempt) => { const statusTone = attemptTone(attempt.state); const sleepLabel = attempt.sleepMs > 0 ? formatDurationLabel(attempt.sleepMs) : "none"; const remainingLabel = attempt.state === "sleeping" && attempt.remainingSleepMs > 0 ? ` (${formatDurationLabel(attempt.remainingSleepMs)} left)` : ""; return (

); })}

); } function ExecutionLog({ events, elapsedMs, }: { events: RetryLogEvent[]; elapsedMs: number; }) { const scrollRef = useRef(null); useEffect(() => { const el = scrollRef.current; if (el) { el.scrollTop = el.scrollHeight; } }, [events.length]); return (

Execution log

{formatElapsedLabel(elapsedMs)}

{events.length === 0 && (

No events yet.

)} {events.map((event, index) => { const tone = eventTone(event.kind); return (

); })}

); } function attemptTone(state: AttemptSnapshot["state"]): { dotClass: string; badgeClass: string; cardClass: string; } { switch (state) { case "running": return { dotClass: "bg-amber-700 animate-pulse", badgeClass: "border-amber-700/40 bg-amber-700/10 text-amber-700", cardClass: "border-amber-700/40 bg-amber-700/10", }; case "sleeping": return { dotClass: "bg-cyan-700 animate-pulse", badgeClass: "border-cyan-700/40 bg-cyan-700/10 text-cyan-700", cardClass: "border-cyan-700/40 bg-cyan-700/10", }; case "failed": return { dotClass: "bg-red-700", badgeClass: "border-red-700/40 bg-red-700/10 text-red-700", cardClass: "border-red-700/40 bg-red-700/10", }; case "succeeded": return { dotClass: "bg-green-700", badgeClass: "border-green-700/40 bg-green-700/10 text-green-700", cardClass: "border-green-700/40 bg-green-700/10", }; case "pending": default: return { dotClass: "bg-gray-500", badgeClass: "border-gray-400/70 bg-background-100 text-gray-900", cardClass: "border-gray-400/40 bg-background-100", }; } } function eventTone(kind: RetryLogEvent["kind"]): { dotClass: string; labelClass: string; } { switch (kind) { case "attempt": return { dotClass: "bg-blue-700", labelClass: "text-blue-700", }; case "fail": return { dotClass: "bg-red-700", labelClass: "text-red-700", }; case "sleep": return { dotClass: "bg-cyan-700", labelClass: "text-cyan-700", }; case "wakeup": return { dotClass: "bg-amber-700", labelClass: "text-amber-700", }; case "success": return { dotClass: "bg-green-700", labelClass: "text-green-700", }; case "exhausted": return { dotClass: "bg-red-700", labelClass: "text-red-700", }; default: return { dotClass: "bg-gray-500", labelClass: "text-gray-900", }; } } [V0_FILE]typescriptreact:file="app/components/retry-code-workbench.tsx" "use client"; import { useEffect, useMemo, useRef, useState } from "react"; type HighlightTone = "amber" | "cyan" | "green" | "red"; type CopyState = "idle" | "copied" | "failed"; type HighlightStyle = { border: string; bg: string; text: string; }; const HIGHLIGHT_STYLES: Record = { amber: { border: "border-amber-700", bg: "bg-amber-700/15", text: "text-amber-700", }, cyan: { border: "border-cyan-700", bg: "bg-cyan-700/15", text: "text-cyan-700", }, green: { border: "border-green-700", bg: "bg-green-700/15", text: "text-green-700", }, red: { border: "border-red-700", bg: "bg-red-700/15", text: "text-red-700", }, }; const CHECKMARK_POINTS = "3,8.5 7,12.5 14,4.5"; type GutterMarkKind = "success" | "fail"; type CodePaneProps = { code: string; htmlLines: string[]; activeLines: number[]; gutterMarks: Record; filename: string; subtitle: string; tone: HighlightTone; }; function CodePane({ code, htmlLines, activeLines, gutterMarks, filename, subtitle, tone, }: CodePaneProps) { const [copyState, setCopyState] = useState("idle"); const activeLineSet = useMemo(() => new Set(activeLines), [activeLines]); const gutterMarkMap = useMemo(() => new Map(Object.entries(gutterMarks).map(([k, v]) => [Number(k), v])), [gutterMarks]); const prevMarkRef = useRef>(new Map()); const isFullReset = gutterMarkMap.size === 0 && activeLines.length === 0; useEffect(() => { if (isFullReset) { prevMarkRef.current.clear(); return; } gutterMarkMap.forEach((kind, line) => { prevMarkRef.current.set(line, kind); }); }, [gutterMarkMap, isFullReset]); const highlightStyle = HIGHLIGHT_STYLES[tone]; const handleCopy = async () => { try { await navigator.clipboard.writeText(code); setCopyState("copied"); window.setTimeout(() => setCopyState("idle"), 1200); } catch { setCopyState("failed"); window.setTimeout(() => setCopyState("idle"), 1200); } }; return (

{filename}

{subtitle}

          
            {htmlLines.map((lineHtml, index) => {
              const lineNumber = index + 1;
              const isActive = activeLineSet.has(lineNumber);
              const markKind = gutterMarkMap.get(lineNumber);
              const displayKind = isFullReset
                ? undefined
                : markKind ?? prevMarkRef.current.get(lineNumber);

              return (
                
                  
                    
                  
                  
                    {lineNumber}
                  
                   0 ? lineHtml : " ",
                    }}
                  />
                
              );
            })}

); } export type RetryCodeWorkbenchProps = { workflowCode: string; workflowHtmlLines: string[]; workflowActiveLines: number[]; workflowGutterMarks: Record; stepCode: string; stepHtmlLines: string[]; stepActiveLines: number[]; stepGutterMarks: Record; tone: HighlightTone; }; export function RetryCodeWorkbench({ workflowCode, workflowHtmlLines, workflowActiveLines, workflowGutterMarks, stepCode, stepHtmlLines, stepActiveLines, stepGutterMarks, tone, }: RetryCodeWorkbenchProps) { return (

); } [V0_FILE]typescript:file="app/components/code-highlight-server.ts" import { highlight } from "sugar-high"; export function highlightCodeToHtmlLines(code: string): string[] { return highlight(code).split("\n"); } [V0_FILE]typescriptreact:file="app/layout.tsx" import type { Metadata } from "next"; import { Geist, Geist_Mono } from "next/font/google"; import "./globals.css"; const geistSans = Geist({ variable: "--font-geist-sans", subsets: ["latin"], }); const geistMono = Geist_Mono({ variable: "--font-geist-mono", subsets: ["latin"], }); export const metadata: Metadata = { title: "Retry with Backoff - Workflow DevKit Example", description: "Demonstrates durable exponential backoff retries with sleep() in Workflow DevKit", }; export default function RootLayout({ children, }: Readonly<{ children: React.ReactNode; }>) { return ( Skip to main content {children} ); } [V0_FILE]typescript:file="app/api/mock/start/route.ts" import { createApiErrorResponse, createApiSuccessResponse } from "../api"; import { buildMockRetrySnapshot, createMockRetryRun, } from "../store"; type StartRequestBody = { contactId?: unknown; maxAttempts?: unknown; failuresBeforeSuccess?: unknown; baseDelayMs?: unknown; }; const DEFAULT_CONTACT_ID = "contact_123"; const DEFAULT_MAX_ATTEMPTS = 5; const DEFAULT_FAILURES_BEFORE_SUCCESS = 2; const DEFAULT_BASE_DELAY_MS = 1_000; function generateRunId(): string { return `retry_${Date.now().toString(36)}_${Math.random().toString(36).slice(2, 8)}`; } function parseBoundedInteger(input: { field: string; value: unknown; min: number; max: number; fallback: number; }): { value: number } | { error: string } { if (input.value === undefined) { return { value: input.fallback }; } if ( typeof input.value !== "number" || !Number.isFinite(input.value) || !Number.isInteger(input.value) ) { return { error: `${input.field} must be an integer between ${input.min} and ${input.max}`, }; } if (input.value < input.min || input.value > input.max) { return { error: `${input.field} must be between ${input.min} and ${input.max}`, }; } return { value: input.value }; } function parseContactId(value: unknown): { value: string } | { error: string } { if (value === undefined) { return { value: DEFAULT_CONTACT_ID }; } if (typeof value !== "string") { return { error: "contactId must be a string" }; } const normalized = value.trim(); if (!normalized) { return { error: "contactId cannot be empty" }; } return { value: normalized }; } function validationErrorResponse( attempted: string, reason: string, body: StartRequestBody ): Response { console.warn("[mock-retry-backoff] start_validation_failed", { attempted, reason, body, }); return createApiErrorResponse( { code: "INVALID_REQUEST", message: reason, }, { status: 400 } ); } export async function POST(request: Request): Promise { let body: StartRequestBody; try { body = (await request.json()) as StartRequestBody; } catch { return createApiErrorResponse( { code: "INVALID_REQUEST", message: "Invalid JSON body", }, { status: 400 } ); } const contactIdResult = parseContactId(body.contactId); if ("error" in contactIdResult) { return validationErrorResponse( "validate_contact_id", contactIdResult.error, body ); } const maxAttemptsResult = parseBoundedInteger({ field: "maxAttempts", value: body.maxAttempts, min: 1, max: 10, fallback: DEFAULT_MAX_ATTEMPTS, }); if ("error" in maxAttemptsResult) { return validationErrorResponse( "validate_max_attempts", maxAttemptsResult.error, body ); } const failuresBeforeSuccessResult = parseBoundedInteger({ field: "failuresBeforeSuccess", value: body.failuresBeforeSuccess, min: 0, max: 20, fallback: DEFAULT_FAILURES_BEFORE_SUCCESS, }); if ("error" in failuresBeforeSuccessResult) { return validationErrorResponse( "validate_failures_before_success", failuresBeforeSuccessResult.error, body ); } const baseDelayMsResult = parseBoundedInteger({ field: "baseDelayMs", value: body.baseDelayMs, min: 50, max: 2_000, fallback: DEFAULT_BASE_DELAY_MS, }); if ("error" in baseDelayMsResult) { return validationErrorResponse( "validate_base_delay_ms", baseDelayMsResult.error, body ); } const run = createMockRetryRun({ runId: generateRunId(), contactId: contactIdResult.value, maxAttempts: maxAttemptsResult.value, failuresBeforeSuccess: failuresBeforeSuccessResult.value, baseDelayMs: baseDelayMsResult.value, }); const snapshot = buildMockRetrySnapshot(run, run.startedAtMs); return createApiSuccessResponse({ runId: run.id, contactId: run.contactId, status: snapshot.status, maxAttempts: run.maxAttempts, failuresBeforeSuccess: run.failuresBeforeSuccess, baseDelayMs: run.baseDelayMs, snapshot, }); } [V0_FILE]typescript:file="app/api/mock/api.ts" import { NextResponse } from "next/server"; type ApiError = { code: string; message: string; }; export function createApiSuccessResponse>( fields: T, init?: ResponseInit ) { return NextResponse.json( { ok: true, ...fields, }, init ); } export function createApiErrorResponse(error: ApiError, init?: ResponseInit) { return NextResponse.json( { ok: false, error, }, init ); } [V0_FILE]typescript:file="app/api/mock/status/route.ts" import { createApiErrorResponse, createApiSuccessResponse } from "../api"; import { buildMockRetrySnapshot, getMockRetryRun } from "../store"; export async function GET(request: Request): Promise { const searchParams = new URL(request.url).searchParams; const runId = searchParams.get("runId"); if (!runId) { return createApiErrorResponse( { code: "INVALID_REQUEST", message: "runId is required", }, { status: 400 } ); } const run = getMockRetryRun(runId); if (!run) { console.warn("[mock-retry-backoff] status_lookup_failed", { attempted: "mock_retry_status_lookup", reason: "run_not_found", runId, }); return createApiErrorResponse( { code: "NOT_FOUND", message: "Run not found", }, { status: 404 } ); } return createApiSuccessResponse(buildMockRetrySnapshot(run)); } [V0_FILE]typescript:file="app/api/mock/store.ts" export const ATTEMPT_WORK_MS = 500; export const MAX_BACKOFF_MS = 8_000; export type MockRunStatus = "running" | "completed" | "failed"; export type AttemptOutcome = "fail" | "success"; export type AttemptRuntimeState = | "pending" | "running" | "failed" | "succeeded" | "sleeping"; export type RetryPhaseKind = "attempt" | "sleep" | "done"; export interface AttemptPlan { attempt: number; startMs: number; endMs: number; sleepMs: number; outcome: AttemptOutcome; } export interface MockRetryRun { id: string; contactId: string; maxAttempts: number; failuresBeforeSuccess: number; baseDelayMs: number; startedAt: string; startedAtMs: number; status: MockRunStatus; plan: AttemptPlan[]; } export interface AttemptSnapshot extends AttemptPlan { state: AttemptRuntimeState; sleepEndMs: number; remainingSleepMs: number; } export interface RetryPhase { phase: RetryPhaseKind; attempt: number | null; nextDelayMs: number | null; } export type RetryLogEventKind = | "attempt" | "fail" | "sleep" | "wakeup" | "success" | "exhausted"; export interface RetryLogEvent { atMs: number; attempt: number; kind: RetryLogEventKind; message: string; } export interface MockRetrySnapshot { runId: string; contactId: string; status: MockRunStatus; maxAttempts: number; failuresBeforeSuccess: number; baseDelayMs: number; attemptWorkMs: number; startedAt: string; startedAtMs: number; elapsedMs: number; totalDurationMs: number; attempts: AttemptSnapshot[]; currentPhase: RetryPhase; executionLog: RetryLogEvent[]; result: | { attempt: number; outcome: "success" | "failed"; } | null; } declare global { // eslint-disable-next-line no-var var __mockRetryBackoffRuns: Map | undefined; } function toIso(timestampMs: number): string { return new Date(timestampMs).toISOString(); } export function getRunStore(): Map { return ( globalThis.__mockRetryBackoffRuns ?? (globalThis.__mockRetryBackoffRuns = new Map()) ); } function computeBackoffDelayMs(baseDelayMs: number, attempt: number): number { return Math.min(MAX_BACKOFF_MS, baseDelayMs * 2 ** (attempt - 1)); } function runStatusTransition( run: MockRetryRun, nextStatus: MockRunStatus, reason: string, context: Record ): void { if (run.status === nextStatus) { return; } console.info("[mock-retry-backoff] run_status_transition", { runId: run.id, from: run.status, to: nextStatus, reason, ...context, }); run.status = nextStatus; } export function buildAttemptPlan(input: { maxAttempts: number; failuresBeforeSuccess: number; baseDelayMs: number; }): AttemptPlan[] { const { maxAttempts, failuresBeforeSuccess, baseDelayMs } = input; const plan: AttemptPlan[] = []; let cursorMs = 0; const successAttempt = failuresBeforeSuccess < maxAttempts ? failuresBeforeSuccess + 1 : null; for (let attempt = 1; attempt <= maxAttempts; attempt += 1) { const startMs = cursorMs; const endMs = startMs + ATTEMPT_WORK_MS; const outcome: AttemptOutcome = successAttempt !== null && attempt === successAttempt ? "success" : "fail"; const hasNextAttempt = attempt < maxAttempts && outcome === "fail"; const sleepMs = hasNextAttempt ? computeBackoffDelayMs(baseDelayMs, attempt) : 0; plan.push({ attempt, startMs, endMs, sleepMs, outcome, }); cursorMs = endMs + sleepMs; if (outcome === "success") { break; } } return plan; } export function createMockRetryRun(input: { runId: string; contactId: string; maxAttempts: number; failuresBeforeSuccess: number; baseDelayMs: number; nowMs?: number; }): MockRetryRun { const nowMs = input.nowMs ?? Date.now(); const run: MockRetryRun = { id: input.runId, contactId: input.contactId, maxAttempts: input.maxAttempts, failuresBeforeSuccess: input.failuresBeforeSuccess, baseDelayMs: input.baseDelayMs, startedAt: toIso(nowMs), startedAtMs: nowMs, status: "running", plan: buildAttemptPlan({ maxAttempts: input.maxAttempts, failuresBeforeSuccess: input.failuresBeforeSuccess, baseDelayMs: input.baseDelayMs, }), }; console.info("[mock-retry-backoff] run_created", { runId: run.id, contactId: run.contactId, maxAttempts: run.maxAttempts, failuresBeforeSuccess: run.failuresBeforeSuccess, baseDelayMs: run.baseDelayMs, planLength: run.plan.length, totalDurationMs: run.plan.at(-1)?.endMs ?? 0, }); getRunStore().set(run.id, run); return run; } export function getMockRetryRun(runId: string): MockRetryRun | undefined { return getRunStore().get(runId); } function buildExecutionTimeline(plan: AttemptPlan[]): RetryLogEvent[] { const events: RetryLogEvent[] = []; for (const attempt of plan) { events.push({ atMs: attempt.startMs, attempt: attempt.attempt, kind: "attempt", message: `Attempt ${attempt.attempt} started`, }); if (attempt.outcome === "success") { events.push({ atMs: attempt.endMs, attempt: attempt.attempt, kind: "success", message: `Attempt ${attempt.attempt} succeeded`, }); continue; } events.push({ atMs: attempt.endMs, attempt: attempt.attempt, kind: "fail", message: `Attempt ${attempt.attempt} failed`, }); if (attempt.sleepMs > 0) { events.push({ atMs: attempt.endMs, attempt: attempt.attempt, kind: "sleep", message: `sleep("${attempt.sleepMs}ms") started`, }); events.push({ atMs: attempt.endMs + attempt.sleepMs, attempt: attempt.attempt, kind: "wakeup", message: `Woke up after ${attempt.sleepMs}ms`, }); } } const finalAttempt = plan.at(-1); if (finalAttempt && finalAttempt.outcome === "fail") { events.push({ atMs: finalAttempt.endMs, attempt: finalAttempt.attempt, kind: "exhausted", message: `Max attempts exhausted (${finalAttempt.attempt})`, }); } return events.sort((left, right) => left.atMs - right.atMs); } export function buildMockRetrySnapshot( run: MockRetryRun, nowMs: number = Date.now() ): MockRetrySnapshot { const elapsedMs = Math.max(0, nowMs - run.startedAtMs); const attempts: AttemptSnapshot[] = run.plan.map((attempt) => ({ ...attempt, state: "pending", sleepEndMs: attempt.endMs + attempt.sleepMs, remainingSleepMs: 0, })); let status: MockRunStatus = "running"; let currentPhase: RetryPhase = { phase: "done", attempt: null, nextDelayMs: null, }; let result: MockRetrySnapshot["result"] = null; for (let index = 0; index < attempts.length; index += 1) { const attempt = attempts[index]; if (elapsedMs < attempt.endMs) { attempt.state = "running"; currentPhase = { phase: "attempt", attempt: attempt.attempt, nextDelayMs: attempt.sleepMs > 0 ? attempt.sleepMs : null, }; break; } if (attempt.outcome === "success") { attempt.state = "succeeded"; status = "completed"; currentPhase = { phase: "done", attempt: attempt.attempt, nextDelayMs: null, }; result = { attempt: attempt.attempt, outcome: "success" }; break; } if (attempt.sleepMs > 0 && elapsedMs < attempt.sleepEndMs) { attempt.state = "sleeping"; attempt.remainingSleepMs = Math.max(0, attempt.sleepEndMs - elapsedMs); currentPhase = { phase: "sleep", attempt: attempt.attempt, nextDelayMs: attempt.sleepMs, }; break; } attempt.state = "failed"; if (index === attempts.length - 1) { status = "failed"; currentPhase = { phase: "done", attempt: attempt.attempt, nextDelayMs: null, }; result = { attempt: attempt.attempt, outcome: "failed" }; break; } } runStatusTransition(run, status, "snapshot_recomputed", { elapsedMs, currentPhase, }); return { runId: run.id, contactId: run.contactId, status, maxAttempts: run.maxAttempts, failuresBeforeSuccess: run.failuresBeforeSuccess, baseDelayMs: run.baseDelayMs, attemptWorkMs: ATTEMPT_WORK_MS, startedAt: run.startedAt, startedAtMs: run.startedAtMs, elapsedMs, totalDurationMs: run.plan.at(-1)?.endMs ?? 0, attempts, currentPhase, executionLog: buildExecutionTimeline(run.plan).filter( (event) => event.atMs <= elapsedMs ), result, }; } [V0_FILE]typescriptreact:file="app/page.tsx" import { highlightCodeToHtmlLines } from "./components/code-highlight-server"; import { RetryBackoffDemo } from "./components/demo"; const directiveUseWorkflow = `"use ${"workflow"}"`; const directiveUseStep = `"use ${"step"}"`; const workflowCode = `import { sleep } from "workflow"; export async function syncCrmContactWithBackoff(contactId: string) { ${directiveUseWorkflow}; const maxAttempts = 5; const baseDelayMs = 1000; let attempt = 1; while (attempt <= maxAttempts) { try { await fetchCrmContact(contactId, attempt); return { contactId, status: "completed", attempts: attempt }; } catch (error) { if (attempt === maxAttempts) { return { contactId, status: "failed", attempts: attempt }; } const delayMs = Math.min(8000, baseDelayMs * 2 ** (attempt - 1)); await sleep(\`${"${delayMs}"}ms\`); attempt += 1; } } return { contactId, status: "failed", attempts: maxAttempts }; }`; const stepCode = `async function fetchCrmContact(contactId: string, attempt: number) { ${directiveUseStep}; const response = await fetch(\`https://crm.example.com/contacts/\${contactId}\`, { method: "GET", headers: { "x-attempt": String(attempt) }, }); if (!response.ok) { throw new Error(\`Transient CRM failure on attempt \${attempt}\`); } const payload = await response.json(); return payload; }`; function buildWorkflowLineMap(code: string) { const lines = code.split("\n"); const attempt = lines .map((line, index) => line.includes("await fetchCrmContact(") ? index + 1 : null ) .filter((line): line is number => line !== null); const sleep = lines .map((line, index) => (line.includes("await sleep(") ? index + 1 : null)) .filter((line): line is number => line !== null); const successReturn = lines .map((line, index) => line.includes('status: "completed"') ? index + 1 : null ) .filter((line): line is number => line !== null); const failureReturn = lines .map((line, index) => line.includes('status: "failed"') && line.includes("attempts: attempt") ? index + 1 : null ) .filter((line): line is number => line !== null); return { attempt, sleep, successReturn, failureReturn, }; } function buildStepLineMap(code: string) { const lines = code.split("\n"); const attempt = lines .map((line, index) => line.includes("const response = await fetch(") ? index + 1 : null ) .filter((line): line is number => line !== null); const successReturn = lines .map((line, index) => (line.includes("return payload;") ? index + 1 : null)) .filter((line): line is number => line !== null); return { attempt, successReturn }; } const workflowHtmlLines = highlightCodeToHtmlLines(workflowCode); const stepHtmlLines = highlightCodeToHtmlLines(stepCode); const workflowLineMap = buildWorkflowLineMap(workflowCode); const stepLineMap = buildStepLineMap(stepCode); export default function Home() { return (

Workflow DevKit Example

Retry with Backoff

Syncing a CRM contact against a flaky API should not require cron jobs or background workers. This workflow retries with exponential backoff and durable{" "} sleep(){" "} between attempts, which means zero compute while waiting.

Try It

{/* ── Why this matters ────────────────────────────────────── */}

Why Not Just Use a Cron Job?

Traditional

You build a retry queue with a database table, a cron job or background worker, and manual bookkeeping for attempt counts, backoff timers, and max-retry thresholds. Failed jobs sit in a table until the next sweep. The {"\u201C"}retry logic{"\u201D"} is scattered across the scheduler, the handler, and the DB schema.

Workflow Retry

A while loop with try/catch{" "} is the retry logic. Each{" "} sleep() is a durable pause at zero compute{"\u2014"}no polling, no timers, no database rows. The attempt counter and backoff math are plain local variables that survive across restarts.

In production, add circuit-breaker logic or alert on max-retries exhausted to avoid silent failures.

); } [V0_FILE]css:file="app/globals.css" @import "tailwindcss"; @theme { --color-background-100: #0a0a0a; --color-background-200: #171717; --color-gray-100: #1a1a1a; --color-gray-200: #1f1f1f; --color-gray-300: #292929; --color-gray-400: #737373; --color-gray-500: #525252; --color-gray-600: #404040; --color-gray-700: #262626; --color-gray-800: #171717; --color-gray-900: #a1a1a1; --color-gray-1000: #ededed; --color-blue-700: #0070F3; --color-red-700: #E5484D; --color-amber-700: #FFB224; --color-green-700: #46A758; --color-violet-700: #8B5CF6; --color-cyan-700: #06B6D4; --font-sans: var(--font-geist-sans); --font-mono: var(--font-geist-mono); } body { background: #0a0a0a; color: #ededed; font-family: var(--font-sans), -apple-system, BlinkMacSystemFont, sans-serif; } /* sugar-high syntax tokens */ :root, .dark { --sh-class: #52a8ff; --sh-identifier: #ededed; --sh-sign: #a1a1a1; --sh-property: #ff6166; --sh-entity: #62c073; --sh-jsxliterals: #ededed; --sh-string: #62c073; --sh-keyword: #f75f8f; --sh-comment: #a1a1a1; } /* Prism token colors - Geist dark-mode palette Extracted from vercel.com/geist/code-block (dark theme) */ .token.keyword, .token.keyword.control-flow { color: #f75f8f; } /* pink - keywords */ .token.plain, .token.parameter, .token.punctuation, .token.plain-text, .token.property-access, .token.operator, .token.tag.punctuation { color: #ededed; } /* gray-1000 - plain text */ .token.function, .token.function.maybe-class-name { color: #bf7af0; } /* purple - functions */ .token.tag { color: #62c073; } /* green - JSX/HTML tags */ .token.literal-property.property { color: #ff6166; } /* red - properties */ .token.string, .token.boolean { color: #62c073; } /* green - strings, booleans */ .token.comment { color: #a1a1a1; } /* gray-900 - comments */ .token.class-name { color: #52a8ff; } /* blue - types */ .token.number { color: #62c073; } /* green - numbers */ .token.attr-name { color: #ff6166; } /* red - attribute names */ .token.attr-value { color: #62c073; } /* green - attribute values */ .token.builtin { color: #52a8ff; } /* blue - builtins */ .token.template-string { color: #62c073; } /* green - template literals */ .token.interpolation { color: #ededed; } /* gray-1000 - interpolation */ [V0_FILE]javascript:file="postcss.config.mjs" export default { plugins: { "@tailwindcss/postcss": {}, }, }; [V0_FILE]typescript:file="workflows/retry-backoff.ts" import { sleep } from "workflow"; export interface ContactSyncResult { contactId: string; status: "completed" | "failed"; attempts: number; lastError?: string; } export interface RetryBackoffConfig { maxAttempts?: number; baseDelayMs?: number; } const DEFAULT_MAX_ATTEMPTS = 5; const DEFAULT_BASE_DELAY_MS = 250; const MAX_BACKOFF_MS = 8_000; function backoffDelayMs(baseDelayMs: number, attempt: number): number { return Math.min(MAX_BACKOFF_MS, baseDelayMs * 2 ** (attempt - 1)); } function normalizeMaxAttempts(value: number | undefined): number { if (typeof value !== "number" || !Number.isInteger(value)) { return DEFAULT_MAX_ATTEMPTS; } return Math.max(1, Math.min(10, value)); } function normalizeBaseDelayMs(value: number | undefined): number { if (typeof value !== "number" || !Number.isFinite(value)) { return DEFAULT_BASE_DELAY_MS; } return Math.max(50, Math.min(2_000, Math.trunc(value))); } export async function retryBackoffContactSync( contactId: string, config: RetryBackoffConfig = {} ): Promise { "use workflow"; const maxAttempts = normalizeMaxAttempts(config.maxAttempts); const baseDelayMs = normalizeBaseDelayMs(config.baseDelayMs); for (let attempt = 1; attempt <= maxAttempts; attempt += 1) { try { await syncContactToCrm(contactId, attempt); return { contactId, status: "completed", attempts: attempt, }; } catch (error) { const lastError = error instanceof Error ? error.message : String(error); if (attempt >= maxAttempts) { return { contactId, status: "failed", attempts: attempt, lastError, }; } const delayMs = backoffDelayMs(baseDelayMs, attempt); await sleep(`${delayMs}ms`); } } return { contactId, status: "failed", attempts: maxAttempts, lastError: "Retry loop exited without a terminal result", }; } async function syncContactToCrm(contactId: string, attempt: number): Promise { "use step"; console.info("[retry-backoff-workflow] sync_contact_attempt", { contactId, attempt, }); // Simulate a flaky downstream API for educational demo purposes. if (attempt < 3) { throw new Error("CRM API returned HTTP 503 Service Unavailable"); } } [V0_FILE]json:file="package.json" { "name": "retry-backoff", "version": "0.1.0", "private": true, "scripts": { "dev": "next dev", "build": "next build", "start": "next start", "lint": "next lint" }, "dependencies": { "next": "16.0.10", "react": "19.2.3", "react-dom": "19.2.3", "sugar-high": "^0.9.5", "workflow": "4.1.0-beta.53" }, "devDependencies": { "@tailwindcss/postcss": "^4", "@types/node": "^20", "@types/react": "^19", "@types/react-dom": "^19", "tailwindcss": "^4", "typescript": "^5" } } [V0_FILE]json:file="tsconfig.json" { "compilerOptions": { "target": "ES2017", "lib": ["dom", "dom.iterable", "esnext"], "allowJs": true, "skipLibCheck": true, "strict": true, "noEmit": true, "esModuleInterop": true, "module": "esnext", "moduleResolution": "bundler", "resolveJsonModule": true, "isolatedModules": true, "jsx": "react-jsx", "incremental": true, "plugins": [ { "name": "next" }, { "name": "workflow" } ], "paths": { "@/*": ["./*"] } }, "include": [ "next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts", ".next/dev/types/**/*.ts", "**/*.mts" ], "exclude": ["node_modules"] } [V0_FILE]markdown:file="tweets.md" # Retry with Backoff — Tweet Thread Variations 5 variations for Day 7. Same code screenshot across all — only the prose changes. **Code screenshot** (used by all variations): \`\`\`ts for (let attempt = 1; attempt <= maxAttempts; attempt++) { try { await syncContactToCrm(contactId, attempt); return { status: "completed", attempts: attempt }; } catch { if (attempt >= maxAttempts) { return { status: "failed", attempts: attempt }; } const delayMs = Math.min(8000, baseDelayMs * 2 ** (attempt - 1)); await sleep(`${delayMs}ms`); } } \`\`\` --- ## Variation A — "What if" Provocation Short, clean rhetorical question. Lets the code do the talking. ### Tweet 1 # 30 Days of Workflow DevKit — Day 7 — Retry with Backoff What if retry logic was just a for-loop — and it survived server restarts? `sleep()` makes that real: ### Tweet 2 The loop pauses between attempts. Really pauses — zero compute. Deploy in between? It wakes up on schedule and runs the next attempt. Fail mid-sync? Only that attempt reruns. Previous work is safe. ### Tweet 3 No retry queue. No backoff table. No state machine. A for-loop that remembers where it was. Explore the interactive demo on v0: --- ## Variation B — Direct Contrast Two-line "old way / new way" framing. Immediately relatable. ### Tweet 1 # 30 Days of Workflow DevKit — Day 7 — Retry with Backoff Traditional: a retry queue, a backoff column, and a cron to sweep stuck jobs. Workflow: a for-loop with `sleep()`: ### Tweet 2 The backoff is just math in a local variable. `sleep()` pauses for real wall time and zero compute while waiting. Crash between attempts? The loop picks up exactly where it left off. ### Tweet 3 No queue. No cron. No dead-letter table. Exponential backoff in a for-loop that survives restarts. Explore the interactive demo on v0: --- ## Variation C — Scenario Opener You're the developer. You're staring at dashboards. ### Tweet 1 # 30 Days of Workflow DevKit — Day 7 — Retry with Backoff CRM returns 503. Retry worker picks it up 30 seconds later. Same 503. You check two dashboards to figure out which attempt you're on. Or you read a for-loop: ### Tweet 2 `attempt` is a local variable. `sleep()` is a real pause. Both survive restarts, deploys, and crashes. No dashboard needed — the state is right there in the code. ### Tweet 3 No retry worker. No dashboards. No backoff table. A for-loop where the attempt counter survives anything. Explore the interactive demo on v0: --- ## Variation D — The Crash Story Opens with the worst-case scenario. Short, punchy sentences. ### Tweet 1 # 30 Days of Workflow DevKit — Day 7 — Retry with Backoff Server crashes mid-backoff. Were you on attempt 3 or 4? Was the delay 2s or 8s? You query the retry table, hope the counter is right. Unless the backoff is just a local variable: ### Tweet 2 `attempt` is a number. `sleep()` is a durable pause. Both survive the crash. No table to query, no state to reconstruct. Deploy between attempt 3 and 4? Wakes up on schedule. ### Tweet 3 No state reconstruction. No counter drift. No retry table. A for-loop that remembers where it was. Explore the interactive demo on v0: --- ## Variation E — Pain Enumeration Classic "So you need X, Y, Z..." but tighter. Gets in and out fast. ### Tweet 1 # 30 Days of Workflow DevKit — Day 7 — Retry with Backoff API goes down. So you set up a retry queue, a backoff table, a dead-letter fallback, a cron to sweep stale jobs... Or you write a for-loop: ### Tweet 2 Each `sleep()` pauses for real wall time. Server reboots at attempt 3? Wakes up for attempt 4 right on schedule. Fail mid-sync? Only that attempt reruns. ### Tweet 3 No retry queue. No backoff table. No dead-letter cron. A for-loop with `sleep()`. That's the whole retry system. Explore the interactive demo on v0: [V0_FILE]typescript:file="next.config.ts" import { withWorkflow } from "workflow/next"; import type { NextConfig } from "next"; const nextConfig: NextConfig = {}; export default withWorkflow(nextConfig);