@stainlessdev/xray-fetch

Fetch API adapter for Stainless X-ray request logging. Use this in edge runtimes, web workers, or any environment with the Fetch API.

Install

``sh
pnpm add @stainlessdev/xray-fetch
`

Basic usage (Fetch handler)

`ts
import { createEmitter, wrapFetch } from '@stainlessdev/xray-fetch';

const xray = createEmitter({
serviceName: 'my-service',
endpointUrl: 'http://localhost:4318',
});

const handler = wrapFetch(async (_req) => {
return new Response('ok', { status: 200 });
}, xray);
`

Preserve request/response objects

If you need to keep the original Request/Response objects (for framework compatibility), use wrapFetchPreserve:

`ts
import { wrapFetchPreserve } from '@stainlessdev/xray-fetch';

const handler = wrapFetchPreserve(async (req) => {
return new Response(await req.text());
}, xray);
`

Access the X-ray context

`ts
import { getXrayContext } from '@stainlessdev/xray-fetch';

const handler = wrapFetch(async (req) => {
const ctx = getXrayContext(req);
ctx?.setUserId('user-123');
return new Response('ok');
}, xray);
`

Request IDs and response headers

X-ray will auto-generate a request ID and inject it into your response headers under the configured name (requestId.header, default request-id, emitted as Request-Id) if the header is missing. If you set your own request ID first (via options.requestId or by setting the response header yourself), X-ray preserves it and does not overwrite the header.

Configuration

createEmitter(config) accepts XrayRuntimeConfig from @stainlessdev/xray-core:

- serviceName (required)
- endpointUrl (required; falls back to STAINLESS_XRAY_ENDPOINT_URL when omitted; explicit endpointUrl wins)
- environment, version, logger, logLevel
- exporter: endpointUrl, headers, timeoutMs, spanProcessor, instance (custom SpanExporter)
- capture: request/response headers and bodies
- redaction: headers/query/body JSON-path redaction
- requestId: header name to read/write
- route: normalization options

Adapter options (WrapOptions)

wrapFetch(handler, xray, options) and wrapFetchPreserve(handler, xray, options) share:

- route: override the route name for the request
- requestId: explicit request ID to use (prevents auto-generation)
- capture: per-request capture overrides
- redaction: per-request redaction overrides
- onRequest(ctx), onResponse(ctx, log), onError(ctx, err) hooks

Notes

- Requires a global fetch when using the default exporter. If fetch is not available, provide exporter.instance or use @stainlessdev/xray-node`.
- This package depends on OpenTelemetry packages as peer dependencies.