---
title: Ceph
icon: /images/ceph-logo.svg
description: Set up Ceph Rados Gateway as a MIRAGE resource from Node or the browser.
---

Ceph Rados Gateway (RGW) speaks the S3 API with AWS Signature V4 against your own gateway endpoint (e.g. `https://ceph.example.com`). RGW is self-hosted, so the endpoint is required and path-style addressing is used by default.

Credentials (RGW user access key + secret key) are created the same way in both runtimes, see [Ceph Credentials](/home/setup/ceph).

## Node (server-side)

```bash
pnpm add @struktoai/mirage-node
```

```ts
import { CephResource, MountMode, Workspace } from '@struktoai/mirage-node'

const ceph = new CephResource({
  bucket: process.env.CEPH_BUCKET!,
  endpoint: process.env.CEPH_ENDPOINT_URL!,
  accessKeyId: process.env.CEPH_ACCESS_KEY_ID!,
  secretAccessKey: process.env.CEPH_SECRET_ACCESS_KEY!,
})

const ws = new Workspace({ '/bucket/': ceph }, { mode: MountMode.READ })
const res = await ws.execute('ls /bucket/')
console.log(res.stdoutText)
```

## Browser (presigned URLs)

```bash
pnpm add @struktoai/mirage-browser
```

The browser `CephResource` is secret-free, your backend signs each operation using your RGW keys and returns a URL. RGW accepts AWS Signature V4, so `@aws-sdk/s3-request-presigner` works, pointed at your gateway endpoint.

### 1. Server: sign URLs with the RGW endpoint

```ts
import {
  CopyObjectCommand,
  DeleteObjectCommand,
  GetObjectCommand,
  HeadObjectCommand,
  ListObjectsV2Command,
  PutObjectCommand,
  S3Client,
} from '@aws-sdk/client-s3'
import { getSignedUrl } from '@aws-sdk/s3-request-presigner'

const client = new S3Client({
  region: 'us-east-1',
  endpoint: process.env.CEPH_ENDPOINT_URL,
  forcePathStyle: true,
  credentials: {
    accessKeyId: process.env.CEPH_ACCESS_KEY_ID!,
    secretAccessKey: process.env.CEPH_SECRET_ACCESS_KEY!,
  },
})
const BUCKET = process.env.CEPH_BUCKET!

app.post('/presign/ceph', async (req, res) => {
  const { path, op, opts } = req.body
  const key = path.replace(/^\/+/, '')
  const ttl = typeof opts?.ttlSec === 'number' ? opts.ttlSec : 300
  let cmd
  switch (op) {
    case 'GET':    cmd = new GetObjectCommand({ Bucket: BUCKET, Key: key }); break
    case 'PUT':    cmd = new PutObjectCommand({ Bucket: BUCKET, Key: key, ContentType: opts?.contentType }); break
    case 'HEAD':   cmd = new HeadObjectCommand({ Bucket: BUCKET, Key: key }); break
    case 'DELETE': cmd = new DeleteObjectCommand({ Bucket: BUCKET, Key: key }); break
    case 'LIST':   cmd = new ListObjectsV2Command({
      Bucket: BUCKET,
      Prefix: opts?.listPrefix,
      Delimiter: opts?.listDelimiter,
      ContinuationToken: opts?.listContinuationToken,
    }); break
    case 'COPY':   cmd = new CopyObjectCommand({
      Bucket: BUCKET,
      Key: key,
      CopySource: `${BUCKET}/${opts?.copySource}`,
    }); break
  }
  res.json({ url: await getSignedUrl(client, cmd, { expiresIn: ttl }) })
})
```

<Warning>
RGW uses **path-style** URLs (`forcePathStyle: true`), virtual-hosted style requires wildcard DNS on the gateway.
</Warning>

### 2. Browser: wire it up

```ts
import { CephResource, MountMode, Workspace } from '@struktoai/mirage-browser'

const ceph = new CephResource({
  bucket: 'my-bucket',
  endpoint: 'https://ceph.example.com',
  presignedUrlProvider: async (path, op, opts) => {
    const r = await fetch('/presign/ceph', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ path, op, opts }),
    })
    const { url } = await r.json()
    return url
  },
})

const ws = new Workspace({ '/bucket/': ceph }, { mode: MountMode.READ })
```

<Tip>
`endpoint` on the browser config is only used for display/logging; the actual endpoint is baked into the presigned URLs your backend returns.
</Tip>

### 3. CORS

RGW supports the S3 `PutBucketCors` call, so the AWS CLI works against your gateway:

```bash
aws s3api put-bucket-cors --bucket "$CEPH_BUCKET" \
  --endpoint-url "$CEPH_ENDPOINT_URL" \
  --cors-configuration '{"CORSRules":[{"AllowedOrigins":["http://localhost:5173","https://app.example.com"],"AllowedMethods":["GET","PUT","HEAD","DELETE","POST"],"AllowedHeaders":["*"],"ExposeHeaders":["ETag","Content-Length","Content-Type","Last-Modified"]}]}'
```

See the [Ceph resource](/python/resource/ceph) docs for the equivalent Python wiring.
