runtime-context-apis.md

Runtime Context APIs

APIs for accessing runtime context information about the current driver, task, or actor.

Getting Runtime Context

ray.runtime_context.get_runtime_context()

Get the runtime context of the current driver/worker.

import ray
from ray import runtime_context

ctx = runtime_context.get_runtime_context()
job_id = ctx.get_job_id()

Context Information

Job and Worker Information

• get_job_id(): Get current job ID
• get_worker_id(): Get current worker ID
• get_node_id(): Get the ID of the node this process is running on
• get_node_labels(): Get node labels of the current worker

Task Information

• get_task_id(): Get current task ID
• get_task_name(): Get current task name
• get_task_function_name(): Get current task function name

Actor Information

• get_actor_id(): Get current actor ID (only in actor context)
• get_actor_name(): Get current actor name (only in actor context)
• current_actor: Get the current actor handle (only in actor context)
• was_current_actor_reconstructed(): Check if actor has been restarted

Resource Information

• get_assigned_resources(): Get resources assigned to this worker
• get_resource_ids(): Get resource IDs
• get_accelerator_ids(): Get visible accelerator IDs
• get_placement_group_id(): Get current placement group ID
• current_placement_group_id: Get current placement group ID (property)

Environment Information

• namespace: Get current namespace
• runtime_env: Get runtime environment used for current driver/worker
• get_runtime_env_string(): Get runtime environment string
• gcs_address: Get GCS address of the Ray cluster

Utility Methods

• get(): Get a dictionary of the current context
• should_capture_child_tasks_in_placement_group(): Check if child tasks should capture parent's placement group

Example

import ray
from ray import runtime_context

@ray.remote
def task():
    ctx = runtime_context.get_runtime_context()
    return {
        "job_id": ctx.get_job_id(),
        "task_id": ctx.get_task_id(),
        "node_id": ctx.get_node_id()
    }

@ray.remote
class Actor:
    def get_context(self):
        ctx = runtime_context.get_runtime_context()
        return {
            "actor_id": ctx.get_actor_id(),
            "job_id": ctx.get_job_id(),
            "was_reconstructed": ctx.was_current_actor_reconstructed()
        }