Function readiness_check 

pub fn readiness_check(
    pool: &State<SharedPool>,
) -> Result<Json<Value>, ErrorResponder>

Readiness check endpoint.

Returns 200 OK if the pool has capacity to handle requests, 503 Service Unavailable otherwise.

Unlike health_check, this actually checks the pool state.

Endpoint

GET /ready

Response

Ready (200 OK)

{
    "status": "ready"
}

Not Ready (503 Service Unavailable)

{
    "status": "not_ready",
    "reason": "no_available_capacity"
}

Readiness Criteria

The service is “ready” if either:

• There are idle browsers available (available > 0), OR
• There is capacity to create new browsers (active < max_pool_size)

Use Cases

• Kubernetes readiness probe
• Load balancer health check (remove from rotation when busy)
• Auto-scaling triggers

Kubernetes Example

readinessProbe:
  httpGet:
    path: /ready
    port: 8000
  initialDelaySeconds: 5
  periodSeconds: 10

Usage in App

rocket::build()
    .manage(pool)
    .mount("/", routes![readiness_check])