Event Monitoring

Kernel Lifecycle Events

• URI: /stream/kernel/_/events

• Method: GET

Provides a continuous message-by-message JSON object stream of kernel lifecycles. It uses HTML5 Server-Sent Events (SSE). Browser-based clients may use the EventSource API for convenience.

New in version v4.20190615: First properly implemented in this version, deprecating prior unimplemented interfaces.

Parameters

Parameter	Type	Description
sessionId	slug	The session ID to monitor the lifecycle events. If set "*", the API will stream events from all kernels visible to the client depending on the client’s role and permissions.
ownerAccessKey	str	(optional) The access key of the owner of the specified session, since different access keys (users) may share a same session ID for different session instances. You can specify this only when the client is either a domain admin or a superadmin.
group	str	The group name to filter the lifecycle events. If set "*", the API will stream events from all kernels visible to the client depending on the client’s role and permissions.

Responses

The response is a continuous stream of UTF-8 text lines following the text/event-stream format. Each event is composed of the event type and data, where the data part is encoded as JSON.

Possible event names (more events may be added in the future):

Event Name	Description
kernel_preparing	The session is just scheduled from the job queue and got an agent resource allocation.
kernel_pulling	The session begins pulling the kernel image (usually from a Docker registry) to the scheduled agent.
kernel_creating	The session is being created as containers (or other entities in different agent backends).
kernel_started	The session becomes ready to execute codes.
kernel_terminated	The session has terminated.

When using the EventSource API, you should add event listeners as follows:

const sse = new EventSource('/stream/kernel/_/events', {
  withCredentials: true,
});
sse.addEventListener('kernel-started', (e) => {
  console.log('kerenl-started', JSON.parse(e.data));
});

Note

The EventSource API must be used with the session-based authentication mode (when the endpoint is a console-server) which uses the browser cookies. Otherwise, you need to manually implement the event stream parser using the standard fetch API running against the manager server.

The event data contains a JSON string like this (more fields may be added in the future):

Field Name	Description
sessionId	The source session ID.
ownerAccessKey	The access key who owns the session.
reason	A short string that describes why the event happened. This may be null or an empty string.
result	Only present for kernel-terminated events. Only meaningful for batch-type sessions. Either one of: "UNDEFINED", "SUCCESS", "FAILURE"

{
  "sessionId": "mysession-01",
  "ownerAccessKey": "MYACCESSKEY",
  "reason": "self-terminated",
  "result": "SUCCESS"
}