Context

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 });