How to dynamically set upstream by request host (tenant)

[edson-nascimento]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the issue has not already been raised

Issue

I'm developing a multi tenant api where:
Each tenant will have a different upstream url that must be dynamically set after identification.
I do the tenant identification by domain hostname.

async function getProxyUrlByTenant(request: FastifyRequest): Promise<string> {
  const tenant = await getTenantByHost(request.hostname);

  if (!tenant) throw new Error('Unauthorized');

  return tenant.apiUrl;
}

// Tenant routes
export async function proxyRoutes(server: FastifyInstance) {
  server.get('/status', async () => {
    return {
      status: 'active',
      at: new Date().toISOString(),
    };
  });

  // Proxy routes
  server.register(proxy, {
    upstream: await getProxyUrlByTenant(/* how get request here ? */),
    prefix: '/proxy',
  });
}

[KaKi87]

How did you implement it ? Thanks