Function is_pool_ready 

pub fn is_pool_ready(pool: &Mutex<BrowserPool>) -> Result<bool, PdfServiceError>

Check if the browser pool is ready to handle requests.

Returns true if the pool has available browsers or capacity to create new ones. This is useful for readiness probes in container orchestration.

Readiness Criteria

The pool is considered “ready” if either:

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

The pool is “not ready” only when:

• All browsers are in use AND the pool is at maximum capacity

Arguments

• pool - Reference to the mutex-wrapped browser pool

Returns

• Ok(true) - Pool can accept new requests
• Ok(false) - Pool is at capacity, requests will queue
• Err(PdfServiceError::PoolLockFailed) - If mutex is poisoned

Use Cases

Kubernetes Readiness Probe

readinessProbe:
  httpGet:
    path: /ready
    port: 8080
  initialDelaySeconds: 5
  periodSeconds: 10

Load Balancer Health Check

When is_pool_ready returns false, the endpoint should return HTTP 503 Service Unavailable to remove the instance from rotation.

Examples

Basic Check

use html2pdf_api::service::is_pool_ready;

if is_pool_ready(&pool)? {
    println!("Pool is ready to accept requests");
} else {
    println!("Pool is at capacity");
}

Request Gating

async fn handle_request(pool: &Mutex<BrowserPool>, request: PdfFromUrlRequest) -> Result<PdfResponse, Error> {
    // Quick capacity check before expensive operation
    if !is_pool_ready(pool)? {
        return Err(Error::ServiceUnavailable("Pool at capacity, try again later"));
    }
     
    // Proceed with PDF generation
    generate_pdf_from_url(pool, &request)
}