Service

A service that processes requests coming from other VMs connected to the data cloud.

Constructors

new Service()

new Service(serviceId, context): Service

Create a new instance of the service with the specified id. It uses the context to make the lifecycle of the service related to the context one.

Parameters

Parameter	Type	Description
serviceId	string	the service id
context	Context	the context of that service.

Returns

Service

Methods

get()

static get(
   service, 
   payload, 
config?): Promise<Object>

Send a request to a Service and wait for a reply with a payload..

Parameters

Parameter	Type	Description
service	string	the service id
payload	Object	the message payload
config?	ServiceConfig	optional parameters for the message

Returns

Promise<Object>

a Promise wrapping the resulting value

---

getPublisher()

static getPublisher(service): Publisher

Returns a Publisher to publish a list of messages to the same service handler, to ensure the messages published are processed by the same processor instead of being balanced between the potential multiple instances of the service.

Parameters

Parameter	Type	Description
service	string	the service id

Returns

Publisher

---

observe()

static observe(
   service, 
   context, 
   payload?, 
   config?): object

Send a request to a Service and subscribe to notifications published from that service.

Parameters

Parameter	Type	Description
service	string	the service id
context	Context	the context used to link its lifecycle to this subscription
payload?	Object	the message payload, optional
config?	SubscriptionServiceConfig	optional parameters for the message

Returns

object

an Observable emitting notifications

observable

observable: Observable<Object>;

publisher

publisher: Publisher;

---

publish()

static publish(service, payload): Promise<void>

Publish a message on the specified service without waiting for any acknowledge

Parameters

Parameter	Type	Description
service	string	the service id
payload	Object

Returns

Promise<void>

---

send()

static send(
   service, 
   payload?, 
config?): Promise<void>

Send a request to a Service and wait for an ack.

Parameters

Parameter	Type	Description
service	string	the service id
payload?	Object	the message payload, optional
config?	ServiceConfig	optional parameters for the message

Returns

Promise<void>

a Promise that completes when the call has been executed

---

listen()

listen(): Observable<ServiceRequest>

Start and listen to incoming requests.

Returns

Observable<ServiceRequest>

---

multicast()

multicast(payload): Promise<void>

Send the given payload to all available instances (e.g.: when running multiple replicas of the same backend) of the current service.

Parameters

Parameter	Type	Description
payload	Object	the message content

Returns

Promise<void>

---

setUnsubscriptionHandler()

setUnsubscriptionHandler(handler): this

Set a function to be executed each time a subscription to that service is closed. The function receives the subscription id that has been closed. The subscription id is the one that has been set and returned by the ServiceRequest.notifyOn method.

Parameters

Parameter	Type	Description
handler	(subId) => void	the handler function to be executed when a subscription is closed.

Returns

this

this Service instance.

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stop()

stop(): void

Stop the service.

Returns

void