Method _get_available_worker

gunicorn/dirty/arbiter.py:583–623

Get an available worker PID using round-robin selection. If app_path is provided, only returns workers that have loaded that specific app. Uses per-app round-robin to ensure fair distribution among eligible workers. Args: app_path: Optional impo

(self, app_path=None)

            await DirtyProtocol.write_message_async(client_writer, response)

    async def _get_available_worker(self, app_path=None):
        """
        Get an available worker PID using round-robin selection.

        If app_path is provided, only returns workers that have loaded
        that specific app. Uses per-app round-robin to ensure fair
        distribution among eligible workers.

        Args:
            app_path: Optional import path of the target app. If None,
                     returns any worker using global round-robin.

        Returns:
            Worker PID or None if no eligible workers are available.
        """
        # Determine eligible workers
        if app_path and self.app_specs:
            # Per-app allocation is configured - must return a worker
            # that has this specific app
            if app_path in self.app_worker_map:
                eligible_pids = list(self.app_worker_map[app_path])
            else:
                # App not known or no workers have it
                return None
        else:
            # No specific app requested, or no app specs configured
            # (backward compatible) - any worker will do
            eligible_pids = list(self.workers.keys())

        if not eligible_pids:
            return None

        # Per-app round-robin for fairness
        if app_path and self.app_specs:
            idx = self._app_rr_indices.get(app_path, 0)
            self._app_rr_indices[app_path] = (idx + 1) % len(eligible_pids)
        else:
            idx = self._worker_rr_index
            self._worker_rr_index = (idx + 1) % len(eligible_pids)

        return eligible_pids[idx % len(eligible_pids)]

    async def _get_worker_connection(self, worker_pid):
        """Get or create connection to a worker."""