queue

What this skill does

# Background Job Queue (Inngest)

Serverless background job queue using [Inngest](https://www.inngest.com). Jobs survive crashes, retry with exponential backoff, report progress, and persist history to Postgres. Works on Vercel — no Redis or worker processes needed.

## Prerequisites

- Next.js app with `src/` directory and App Router
- `db` skill applied (Drizzle + Postgres)
- `env-config` skill applied (Zod env validation)
- `auth` skill applied (for user context)

## Installation

```bash
bun add inngest
```

## Environment Variables

Add to `.env.local`:

```env
# Inngest
INNGEST_EVENT_KEY=local
INNGEST_SIGNING_KEY=local
```

Add to `src/env.ts` server schema:

```typescript
INNGEST_EVENT_KEY: z.string().default("local"),
INNGEST_SIGNING_KEY: z.string().default("local"),
```

## What Gets Created

```
src/
├── app/
│   └── api/
│       ├── inngest/
│       │   └── route.ts              # Inngest serve endpoint
│       └── jobs/
│           ├── route.ts              # GET list jobs, POST submit job
│           └── [id]/
│               └── route.ts          # GET job status/result
└── lib/
    ├── db/
    │   └── schema/
    │       └── jobs.ts               # Drizzle schema: jobs table
    └── queue/
        ├── client.ts                 # Inngest client setup
        ├── types.ts                  # Job types and event schemas
        └── functions/
            └── example-job.ts        # Example Inngest function
```

## Setup Steps

### Step 1: Create `src/lib/db/schema/jobs.ts`

```typescript
import { pgTable, text, integer, timestamp, jsonb, uuid } from "drizzle-orm/pg-core";

export const jobs = pgTable("jobs", {
  id: uuid("id").primaryKey().defaultRandom(),
  userId: text("user_id").notNull(),
  type: text("type").notNull(),
  status: text("status", {
    enum: ["queued", "running", "completed", "failed"],
  }).notNull().default("queued"),
  progress: integer("progress").notNull().default(0),
  input: jsonb("input"),
  result: jsonb("result"),
  error: text("error"),
  inngestRunId: text("inngest_run_id"),
  startedAt: timestamp("started_at", { withTimezone: true }),
  completedAt: timestamp("completed_at", { withTimezone: true }),
  createdAt: timestamp("created_at", { withTimezone: true }).defaultNow().notNull(),
  updatedAt: timestamp("updated_at", { withTimezone: true }).defaultNow().notNull(),
});

export type Job = typeof jobs.$inferSelect;
export type NewJob = typeof jobs.$inferInsert;
```

### Step 2: Add export to `src/lib/db/schema/index.ts`

Find the existing exports in `src/lib/db/schema/index.ts` and add:

```typescript
export * from "./jobs";
```

### Step 3: Create `src/lib/queue/types.ts`

```typescript
type JobEventBase = {
  data: {
    jobId: string;
    userId: string;
  };
};

export type QueueEvents = {
  "job/example": JobEventBase & {
    data: JobEventBase["data"] & {
      prompt: string;
    };
  };
};
```

### Step 4: Create `src/lib/queue/client.ts`

```typescript
import { Inngest } from "inngest";

export const inngest = new Inngest({
  id: "my-app",
});
```

> **Note:** The Inngest client is intentionally untyped at the client level. Type safety is enforced per-function via `createFunction()` event triggers. This allows the generic `/api/jobs` route to send events for any job type without type conflicts.

### Step 5: Create `src/lib/queue/functions/example-job.ts`

```typescript
import { inngest } from "@/lib/queue/client";
import { db } from "@/lib/db";
import { jobs } from "@/lib/db/schema";
import { eq } from "drizzle-orm";

export const exampleJob = inngest.createFunction(
  {
    id: "example-job",
    retries: 3,
  },
  { event: "job/example" },
  async ({ event, step }) => {
    const { jobId, userId, prompt } = event.data;

    // Mark as running
    await step.run("mark-running", async () => {
      await db
        .update(jobs)
        .set({
          status: "running",
          startedAt: new Date(),
          updatedAt: new Date(),
        })
        .where(eq(jobs.id, jobId));
    });

    // Simulate work with progress updates
    const result = await step.run("process", async () => {
      // Update progress to 50%
      await db
        .update(jobs)
        .set({ progress: 50, updatedAt: new Date() })
        .where(eq(jobs.id, jobId));

      // Do the actual work here
      const output = { message: `Processed: ${prompt}`, timestamp: Date.now() };

      // Update progress to 100%
      await db
        .update(jobs)
        .set({ progress: 100, updatedAt: new Date() })
        .where(eq(jobs.id, jobId));

      return output;
    });

    // Mark as completed
    await step.run("mark-completed", async () => {
      await db
        .update(jobs)
        .set({
          status: "completed",
          result,
          completedAt: new Date(),
          updatedAt: new Date(),
        })
        .where(eq(jobs.id, jobId));
    });

    return result;
  }
);
```

### Step 6: Create `src/app/api/inngest/route.ts`

```typescript
import { serve } from "inngest/next";
import { inngest } from "@/lib/queue/client";
import { exampleJob } from "@/lib/queue/functions/example-job";

export const { GET, POST, PUT } = serve({
  client: inngest,
  functions: [exampleJob],
});
```

### Step 7: Create `src/app/api/jobs/route.ts`

```typescript
import { NextResponse } from "next/server";
import { z } from "zod";
import { db } from "@/lib/db";
import { jobs } from "@/lib/db/schema";
import { eq, desc } from "drizzle-orm";
import { inngest } from "@/lib/queue/client";
import { auth } from "@/lib/auth";
import { headers } from "next/headers";

const submitSchema = z.object({
  type: z.string(),
  input: z.record(z.string(), z.unknown()).optional(),
});

export async function GET(request: Request) {
  const session = await auth.api.getSession({
    headers: await headers(),
  });
  if (!session?.user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  const userJobs = await db
    .select()
    .from(jobs)
    .where(eq(jobs.userId, session.user.id))
    .orderBy(desc(jobs.createdAt))
    .limit(50);

  return NextResponse.json(userJobs);
}

export async function POST(request: Request) {
  const session = await auth.api.getSession({
    headers: await headers(),
  });
  if (!session?.user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  const body = await request.json();
  const { type, input } = submitSchema.parse(body);

  // Create job record
  const [job] = await db
    .insert(jobs)
    .values({
      userId: session.user.id,
      type,
      input,
    })
    .returning();

  // Send event to Inngest
  await inngest.send({
    name: `job/${type}`,
    data: {
      jobId: job.id,
      userId: session.user.id,
      ...((input as Record<string, unknown>) ?? {}),
    },
  });

  return NextResponse.json(job, { status: 201 });
}
```

### Step 8: Create `src/app/api/jobs/[id]/route.ts`

```typescript
import { NextResponse } from "next/server";
import { db } from "@/lib/db";
import { jobs } from "@/lib/db/schema";
import { eq, and } from "drizzle-orm";
import { auth } from "@/lib/auth";
import { headers } from "next/headers";

export async function GET(
  _request: Request,
  { params }: { params: Promise<{ id: string }> }
) {
  const session = await auth.api.getSession({
    headers: await headers(),
  });
  if (!session?.user) {
    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
  }

  const { id } = await params;

  const [job] = await db
    .select()
    .from(jobs)
    .where(and(eq(jobs.id, id), eq(jobs.userId, session.user.id)))
    .limit(1);

  if (!job) {
    return NextResponse.json({ error: "Job not found" }, { status: 404 });
  }

  return NextResponse.json(job);
}
```

### Step 9: Push database schema

```bash
bunx drizzle-kit push
```

## Usage

### Submit a job

```typescript
const response = await fetch("/api/jobs", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: J