When you call an action or emit an event, the broker creates a Context instance that contains all request information and passes it to the action/event handler as a single argument.

Properties of Context

Name	Type	Description
`ctx.id`	`String`	Context ID
`ctx.broker`	`ServiceBroker`	Instance of the broker.
`ctx.nodeID`	`String`	The caller or target Node ID.
`ctx.action`	`Object`	Instance of action definition.
`ctx.event`	`Object`	Instance of event definition.
`ctx.eventName`	`Object`	The emitted event name.
`ctx.eventType`	`String`	Type of event (“emit” or “broadcast”).
`ctx.eventGroups`	`Array<String>`	Groups of event.
`ctx.caller`	`String`	Service full name of the caller. E.g.: `v3.myService`
`ctx.requestID`	`String`	Request ID. If you make nested-calls, it will be the same ID.
`ctx.parentID`	`String`	Parent context ID (in nested-calls).
`ctx.params`	`Any`	Request params. Second argument from `broker.call`.
`ctx.meta`	`Any`	Request metadata. It will be also transferred to nested-calls.
`ctx.locals`	`Any`	Local data.
`ctx.level`	`Number`	Request level (in nested-calls). The first level is `1`.
`ctx.span`	`Span`	Current active span.

Methods of Context

Name	Response	Description
`ctx.call()`	`Promise`	Make nested-call. Same arguments like in `broker.call`
`ctx.emit()`	`void`	Emit an event, same as `broker.emit`
`ctx.broadcast()`	`void`	Broadcast an event, same as `broker.broadcast`
`ctx.startSpan(name, opts)`	`Span`	Creates a new child span.
`ctx.finishSpan(span)`	`void`	Finishes a span.
`ctx.toJSON()`	`Object`	Convert `Context` to a printable JSON.
`ctx.copy()`	`this`	Create a copy of the `Context` instance.

Context tracking

If you want graceful service shutdowns, enable the Context tracking feature in broker options. If you enable it, all services will wait for all running contexts before shutdown. A timeout value can be defined with shutdownTimeout broker option. The default values is 5 seconds.

Enable context tracking & change the timeout value

const broker = new ServiceBroker({
    nodeID: "node-1",
    tracking: {
        enabled: true,
        shutdownTimeout: 10 * 1000
    }
});

The shutdown timeout can be overwritten by $shutdownTimeout property in service settings.

Disable tracking in calling option

await broker.call("posts.find", {}, { tracking: false });