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CloudEventsReceiver

@webda/cloudevents

Class: CloudEventsReceiver<T>

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:234

Receive CloudEvents over HTTP and dispatch them to handlers

The POST route accepts the three HTTP content modes of the CloudEvents binding: binary (ce-* headers), structured (application/cloudevents+json) and batch (application/cloudevents-batch+json). It is the sink of a Knative Trigger (the Webda/KnativeDeployer triggers parameter generates them), of a CloudEvents Subscription, or of any producer posting CloudEvents.

Response contract: 202 acknowledges the events (200 with the reply CloudEvent when a handler returns one), 400 refuses a malformed or invalid event (the sender must not retry it) and a handler failure answers 500 so the sender retries (Knative retries then dead-letters). Delivery is at-least-once: handlers must be idempotent, dedupe only filters the retries reaching the same replica.

Handlers are registered by exact type or predicate with subscribe(), or declared with the @CloudEventHandler("com.acme.type") decorator on any service. The CloudEvents.Received, CloudEvents.Handled and CloudEvents.Failed Webda events are emitted around the dispatch.

"CloudEventsReceiver": { "type": "Webda/CloudEventsReceiver", "url": "/cloudevents", "dedupe": true }

Webda Modda​

Extends​

Type Parameters​

T​

T extends CloudEventsReceiverParameters = CloudEventsReceiverParameters

Constructors​

Constructor​

new CloudEventsReceiver<T>(name, params): CloudEventsReceiver<T>

Defined in: core/lib/services/service.d.ts:72

Create a new Service instance

Service

Parameters​

name​

string

The name of the service

params​

T

The parameters block define in the configuration file

Returns​

CloudEventsReceiver<T>

Inherited from​

Service<T, CloudEventsReceiverEvents>.constructor

Properties​

_compiledCapabilities​

protected _compiledCapabilities: Record<string, any>

Defined in: core/lib/services/iservice.d.ts:50

Capabilities detected at compile-time from @WebdaCapability-tagged interfaces.

Populated during Service.resolve by reading the service's entry in webda.module.json. Each key is a capability name (e.g., "request-filter"), and the value is an empty object {} by default. Override getCapabilities to provide capability-specific configuration or to conditionally disable capabilities.

See​

getCapabilities

Inherited from​

KnativeBrokerPubSub._compiledCapabilities

[WEBDA_EVENTS]​

[WEBDA_EVENTS]: CloudEventsReceiverEvents

Defined in: core/lib/services/service.d.ts:50

Set the Webda events here

Inherited from​

Service.[WEBDA_EVENTS]

discovered​

protected discovered: WeakSet<object>

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:262

Services whose @CloudEventHandler methods are registered

filter?​

protected optional filter?: FilterImplementation<Filter>

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:254

The resolved filters parameter

handlers​

protected handlers: CloudEventHandlerRegistration[] = []

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:250

The registered handlers, in registration order

logger​

protected logger: Logger

Defined in: core/lib/services/service.d.ts:59

Logger with class context

Inherited from​

KnativeBrokerPubSub.logger

metrics​

protected metrics: object

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:240

duplicates​

duplicates: Counter

failed​

failed: Counter

filtered​

filtered: Counter

received​

received: Counter

rejected​

rejected: Counter

Overrides​

Service.metrics

name​

readonly name: string

Defined in: core/lib/services/iservice.d.ts:27

Name

Inherited from​

KnativeBrokerPubSub.name

parameters​

readonly parameters: T

Defined in: core/lib/services/iservice.d.ts:31

Parameters

Inherited from​

Service.parameters

seen​

protected seen: Map<string, number>

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:258

source + id of the handled events with their expiry, for dedupe

createConfiguration?​

static optional createConfiguration?: (params) => any

Defined in: core/lib/services/iservice.d.ts:35

Create configuration set by the application on load

Parameters​

params​

any

Returns​

any

Inherited from​

Service.createConfiguration

filterConfiguration?​

static optional filterConfiguration?: (params) => any

Defined in: core/lib/services/iservice.d.ts:39

Create configuration set by the application on load

Parameters​

params​

any

Returns​

any

Inherited from​

Service.filterConfiguration

Parameters​

static Parameters: typeof ServiceParameters

Defined in: core/lib/services/service.d.ts:46

Service parameters

Inherited from​

Service.Parameters

Methods​

__clean()​

abstract __clean(): Promise<void>

Defined in: core/lib/services/service.d.ts:224

Clean the service data, can only be used in test mode

Returns​

Promise<void>

Inherited from​

Service.__clean

addListener()​

addListener<Key>(eventName, listener): this

Defined in: core/lib/events/asynceventemitter.d.ts:87

Add listener

Type Parameters​

Key​

Key extends keyof CloudEventsReceiverEvents

Parameters​

eventName​

Key

the event name

listener​

(event) => void | Promise<void>

the event listener

Returns​

this

this for chaining

See​

EventEmitter.addListener

Inherited from​

Service.addListener

addRoute()​

protected addRoute(url, methods, executer, openapi?, override?): void

Defined in: core/lib/services/service.d.ts:177

Add a route dynamicaly

Parameters​

url​

string

of the route can contains dynamic part like {uuid}

methods​

HttpMethodType[]

the HTTP methods

executer​

Function

Method to execute for this route

openapi?​

OpenAPIWebdaDefinition

the OpenAPI specification

override?​

boolean

whether to override existing

Returns​

void

Inherited from​

Service.addRoute

authorizeClientEvent()​

authorizeClientEvent(_event, _context): boolean

Defined in: core/lib/services/service.d.ts:153

Authorize a public event subscription

Parameters​

_event​

string

the event name

_context​

OperationContext

the execution context

Returns​

boolean

true if the condition is met

Inherited from​

Service.authorizeClientEvent

computeParameters()​

computeParameters(): void

Defined in: core/lib/services/service.d.ts:77

Used to compute or derivate input parameter to attribute

Returns​

void

Deprecated​

Inherited from​

Service.computeParameters

discoverHandlers()​

discoverHandlers(services): void

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:318

Register the @CloudEventHandler methods of services

Called with every service when the receiver initializes; call it for a service added afterwards. A service is discovered once.

Parameters​

services​

Iterable<AbstractService<ServiceParameters, { }>>

the services to scan

Returns​

void

dispatch()​

dispatch(event, context): Promise<CloudEvent<undefined> | undefined>

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:458

Dispatch an event to its handlers

Parameters​

event​

CloudEvent

the event

context​

WebContext

the request delivering it

Returns​

Promise<CloudEvent<undefined> | undefined>

the reply of the first handler returning one

Throws​

WebdaError.HttpError the error of a handler (500 unless the handler threw an HttpError)

emit()​

emit<Key>(event, data): Promise<void>

Defined in: core/lib/services/service.d.ts:213

Emit the event with data and wait for Promise to finish if listener returned a Promise

Type Parameters​

Key​

Key extends keyof CloudEventsReceiverEvents

Parameters​

event​

Key

the event name

data​

CloudEventsReceiverEvents[Key]

the data to process

Returns​

Promise<void>

Inherited from​

Service.emit

getCapabilities()​

getCapabilities(): Record<string, any>

Defined in: core/lib/services/iservice.d.ts:72

Return the capabilities of this service.

By default returns capabilities detected at compile-time from

Returns​

Record<string, any>

the result

Webda Capability-tagged​

interfaces in webda.module.json.

Override to disable capabilities based on configuration:

getCapabilities() {
  const caps = super.getCapabilities();
  if (!this.parameters.enabled) delete caps["request-filter"];
  return caps;
}

Inherited from​

Service.getCapabilities

getClientEvents()​

getClientEvents(): string[]

Defined in: core/lib/services/service.d.ts:144

Return the events that an external system can subscribe to

Returns​

string[]

the list of results

Inherited from​

Service.getClientEvents

getDedupeKey()​

protected getDedupeKey(event): string

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:412

Key of an event in the dedupe cache

Parameters​

event​

CloudEvent

the event

Returns​

string

the key

getHandlers()​

getHandlers(event): CloudEventHandlerFunction<any>[]

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:363

Handlers of an event

Parameters​

event​

CloudEvent

the event

Returns​

CloudEventHandlerFunction<any>[]

the handlers whose matcher accepts it

getMaxListeners()​

getMaxListeners(): number

Defined in: core/lib/events/asynceventemitter.d.ts:91

Returns​

number

Inherited from​

Service.getMaxListeners

getMetric()​

getMetric<T>(type, configuration): T

Defined in: core/lib/services/service.d.ts:138

Add service name label

Type Parameters​

T​

T = Counter<string> | Gauge<string> | Histogram<string>

Parameters​

type​

CustomConstructor<T, [MetricConfiguration<T>]>

the type to look up

configuration​

MetricConfiguration<T>

the configuration

Returns​

T

the result

Inherited from​

Service.getMetric

getName()​

getName(): string

Defined in: core/lib/services/service.d.ts:218

Get service name

Returns​

string

the result string

Inherited from​

Service.getName

getOpenApiReplacements()​

getOpenApiReplacements(): any

Defined in: core/lib/services/service.d.ts:182

Return variables for replacement in openapi

Returns​

any

the result

Inherited from​

Service.getOpenApiReplacements

getOperationId()​

getOperationId(id): string | undefined

Defined in: core/lib/services/service.d.ts:167

If undefined is returned it cancel the operation registration

Parameters​

id​

string

the identifier

Returns​

string | undefined

the result

Inherited from​

Service.getOperationId

getParameters()​

getParameters(): T

Defined in: core/lib/services/service.d.ts:82

Get the service parameters

Returns​

T

the result

Inherited from​

Service.getParameters

getService()​

getService<T>(name): ServicesMap[T]

Defined in: core/lib/services/service.d.ts:131

Get a service by name

Type Parameters​

T​

T extends keyof ServicesMap

Parameters​

name​

T

the name to use

Returns​

ServicesMap[T]

the result map

Deprecated​

Use useService, might reconsider

Inherited from​

Service.getService

getState()​

getState(): ServiceStates

Defined in: core/lib/services/service.d.ts:55

Get the current state

Returns​

ServiceStates

the result

Inherited from​

Service.getState

getUrl()​

getUrl(url, _methods): string

Defined in: core/lib/services/service.d.ts:161

Return the full path url based on parameters

Parameters​

url​

string

relative url to service

_methods​

HttpMethodType[]

in case we need filtering (like Store)

Returns​

string

absolute url or undefined if need to skip the Route

Inherited from​

Service.getUrl

init()​

init(): Promise<CloudEventsReceiver<T>>

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:304

Register the @CloudEventHandler methods of every service

Returns​

Promise<CloudEventsReceiver<T>>

Overrides​

Service.init

initMetrics()​

initMetrics(): void

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:267

Returns​

void

Overrides​

Service.initMetrics

initOperations()​

initOperations(): void

Defined in: core/lib/services/service.d.ts:195

Init the operations from

Returns​

void

Operation​

decorators on this service

Inherited from​

Service.initOperations

isDuplicate()​

isDuplicate(event): boolean

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:422

Whether dedupe already handled the event

Parameters​

event​

CloudEvent

the event

Returns​

boolean

true when a handled event had the same source and id within dedupeTtl

listeners()​

listeners(eventName): Function[]

Defined in: core/lib/events/asynceventemitter.d.ts:151

Get all listeners for an event

Parameters​

eventName​

keyof CloudEventsReceiverEvents

the event name

Returns​

Function[]

the list of results

Inherited from​

Service.listeners

loadCapabilities()​

protected loadCapabilities(): void

Defined in: core/lib/services/service.d.ts:120

Load capabilities from webda.module.json metadata into _compiledCapabilities.

Called during resolve after dependency injection. Reads the service's type name from parameters, looks it up in the application's module metadata (moddas or beans section), and populates _compiledCapabilities with an empty object for each declared capability name.

Fails silently if the application is not available (e.g., in unit tests where services are instantiated without a full application context).

Returns​

void

Example​

// If webda.module.json contains:
// { "moddas": { "MyApp/HawkService": { "capabilities": ["request-filter", "cors-filter"] } } }
// Then after resolve(), this.getCapabilities() returns:
// { "request-filter": {}, "cors-filter": {} }

See​

getCapabilities

Inherited from​

Service.loadCapabilities

log()​

log(level, ...args): void

Defined in: core/lib/services/service.d.ts:236

Log operation

Parameters​

level​

WorkerLogLevel

to log

args​

...any[]

additional arguments

Returns​

void

Inherited from​

Service.log

off()​

off<Key>(eventName, listener): this

Defined in: core/lib/events/asynceventemitter.d.ts:127

Perform off

Type Parameters​

Key​

Key extends keyof CloudEventsReceiverEvents

Parameters​

eventName​

Key

the event name

listener​

(event) => void

the event listener

Returns​

this

this for chaining

See​

EventEmitter.off

Inherited from​

Service.off

on()​

on<Key>(eventName, listener): this

Defined in: core/lib/events/asynceventemitter.d.ts:111

Perform on

Type Parameters​

Key​

Key extends keyof CloudEventsReceiverEvents

Parameters​

eventName​

Key

the event name

listener​

(event) => void

the event listener

Returns​

this

this for chaining

See​

EventEmitter.once

Inherited from​

Service.on

once()​

once<Key>(eventName, listener): this

Defined in: core/lib/events/asynceventemitter.d.ts:103

Perform once

Type Parameters​

Key​

Key extends keyof CloudEventsReceiverEvents

Parameters​

eventName​

Key

the event name

listener​

(event) => void

the event listener

Returns​

this

this for chaining

See​

EventEmitter.once

Inherited from​

Service.once

operationSchemaName()​

protected operationSchemaName(method, side): string

Defined in: core/lib/services/service.d.ts:191

Schema of an operation side: <service name>.<method>.<side> when the application knows it, else the one the build writes, <class>.<method>.<side>, for the class or its nearest ancestor that has it (a service configured under another name than its class)

Parameters​

method​

string

the method name

side​

"input" | "output"

input or output

Returns​

string

the schema name

Inherited from​

Service.operationSchemaName

parse()​

parse(context): Promise<{ batch: boolean; events: CloudEvent<undefined>[]; }>

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:376

Parse the request into CloudEvents

Parameters​

context​

WebContext

the request

Returns​

Promise<{ batch: boolean; events: CloudEvent<undefined>[]; }>

the events, and whether the request was a batch

Throws​

WebdaError.BadRequest when the request is not a CloudEvent, or an invalid one

receive()​

receive(context): Promise<void>

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:552

Receive one event, or a batch, and dispatch them

A batch is acknowledged as a whole: a failing handler refuses the whole batch, the sender redelivers it.

Parameters​

context​

WebContext

the request

Returns​

Promise<void>

remember()​

protected remember(event): void

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:440

Remember a handled event for dedupe

Parameters​

event​

CloudEvent

the event

Returns​

void

removeAllListeners()​

removeAllListeners<Key>(eventName?): this

Defined in: core/lib/events/asynceventemitter.d.ts:134

Remove all listeners

Type Parameters​

Key​

Key extends keyof CloudEventsReceiverEvents

Parameters​

eventName?​

Key

the event name

Returns​

this

this for chaining

See​

EventEmitter.removeAllListeners

Inherited from​

Service.removeAllListeners

removeListener()​

removeListener<Key>(eventName, listener): this

Defined in: core/lib/events/asynceventemitter.d.ts:119

Remove listener

Type Parameters​

Key​

Key extends keyof CloudEventsReceiverEvents

Parameters​

eventName​

Key

the event name

listener​

(event) => void

the event listener

Returns​

this

this for chaining

See​

EventEmitter.removeListener

Inherited from​

Service.removeListener

resolve()​

resolve(): this

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:291

Returns​

this

Overrides​

Service.resolve

respond()​

protected respond(context, replies, batch): void

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:515

Write the response: 202 without reply, 200 with the reply in binary mode (a batch of replies in batch mode)

Parameters​

context​

WebContext

the request

replies​

CloudEvent<undefined>[]

the replies of the handlers

batch​

boolean

whether the request was a batch

Returns​

void

setMaxListeners()​

setMaxListeners(n): this

Defined in: core/lib/events/asynceventemitter.d.ts:95

Parameters​

n​

number

Returns​

this

Inherited from​

Service.setMaxListeners

stop()​

stop(): Promise<void>

Defined in: core/lib/services/service.d.ts:86

Shutdown the current service if action need to be taken

Returns​

Promise<void>

Inherited from​

Service.stop

subscribe()​

subscribe<D>(matcher, handler): () => void

Defined in: cloudevents/src/services/cloudeventsreceiver.service.ts:346

Register a handler

Not named on: Service.on listens to the Webda events of the service.

Type Parameters​

D​

D = any

Parameters​

matcher​

CloudEventMatcher

exact type of the events, or a predicate

handler​

CloudEventHandlerFunction<D>

receives the matching events

Returns​

a function removing the handler

() => void

toJSON()​

toJSON(): string

Defined in: core/lib/services/service.d.ts:200

Prevent service to be serialized

Returns​

string

the result

Inherited from​

Service.toJSON

toString()​

toString(): string

Defined in: core/lib/services/service.d.ts:91

Return service representation

Returns​

string

the result

Inherited from​

Service.toString