PURISTA API / Modules / @purista/core / DefaultEventBridge

Class: DefaultEventBridge

@purista/core.DefaultEventBridge

Simple implementation of some simple in-memory event bridge. Does not support threads and does not need any external databases.

Example

import { DefaultEventBridge } from '@purista/core'

const eventBridge = new DefaultEventBridge()
await eventBridge.start()

// add your services

Hierarchy

• EventBridgeBaseClass<DefaultEventBridgeConfig>

  ↳ DefaultEventBridge

Implements

• EventBridge

Table of contents

Constructors

• constructor

Properties

• config
• defaultCommandTimeout
• hasStarted
• healthy
• instanceId
• logger
• name
• pendingInvocations
• readStream
• runningSubscriptionCount
• serviceFunctions
• subscriptions
• traceProvider
• writeStream

Methods

• destroy
• emit
• emitMessage
• getTracer
• invoke
• isHealthy
• isReady
• off
• on
• registerCommand
• registerSubscription
• removeAllListeners
• start
• startActiveSpan
• unregisterCommand
• unregisterSubscription
• wrapInSpan

Constructors

constructor

• new DefaultEventBridge(config?): DefaultEventBridge

Parameters

Name	Type	Description
config?	Object	-
config.defaultCommandTimeout?	number	Overwrite the hardcoded default timeout of command invocations
config.emitMessagesAsEventBridgeEvents?	boolean	Emit messages which have an event name set as javascript events on the event bridge instance
config.instanceId?	string	The instance id of the event bridge. If not set, a id will generated each time a instance is created. Use this if there is a need to always have the same instance id.
config.logLevel?	LogLevelName	If no logger instance is given, use this log level
config.logWarnOnMessagesWithoutReceiver?	boolean	Log warnings on messages which are emitted, but could not delivered to at least one receiver
config.logger?	Logger	A logger instance
config.spanProcessor?	SpanProcessor	A OpenTelemetry span processor

Returns

DefaultEventBridge

Overrides

EventBridgeBaseClass.constructor

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:83

Properties

config

• config: Complete<{ defaultCommandTimeout?: number ; emitMessagesAsEventBridgeEvents?: boolean ; instanceId?: string ; logLevel?: LogLevelName ; logWarnOnMessagesWithoutReceiver?: boolean ; logger?: Logger ; spanProcessor?: SpanProcessor }>

Inherited from

EventBridgeBaseClass.config

Defined in

core/EventBridge/EventBridgeBaseClass.impl.ts:21

---

defaultCommandTimeout

• defaultCommandTimeout: number

The default time until when a command invocation automatically returns a time out error

Implementation of

EventBridge.defaultCommandTimeout

Inherited from

EventBridgeBaseClass.defaultCommandTimeout

Defined in

core/EventBridge/EventBridgeBaseClass.impl.ts:27

---

hasStarted

• Protected hasStarted: boolean = false

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:80

---

healthy

• Protected healthy: boolean = false

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:81

---

instanceId

• instanceId: string

Implementation of

EventBridge.instanceId

Inherited from

EventBridgeBaseClass.instanceId

Defined in

core/EventBridge/EventBridgeBaseClass.impl.ts:25

---

logger

• logger: Logger

Inherited from

EventBridgeBaseClass.logger

Defined in

core/EventBridge/EventBridgeBaseClass.impl.ts:18

---

name

• name: string

Implementation of

EventBridge.name

Inherited from

EventBridgeBaseClass.name

Defined in

core/EventBridge/EventBridgeBaseClass.impl.ts:23

---

pendingInvocations

• Protected pendingInvocations: Map<string, PendigInvocation>

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:75

---

readStream

• Protected readStream: Readable

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:63

---

runningSubscriptionCount

• Protected runningSubscriptionCount: number = 0

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:76

---

serviceFunctions

• Protected serviceFunctions: Map<string, (message: { contentEncoding: string ; contentType: string ; correlationId: string ; eventName?: string ; id: string ; messageType: Command ; otp?: string ; payload: { parameter: unknown ; payload: unknown } ; principalId?: string ; receiver: EBMessageAddress ; sender: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; tenantId?: string ; timestamp: number ; traceId?: string }) => Promise<{ contentEncoding: "utf-8" ; contentType: "application/json" ; correlationId: string ; eventName?: string ; id: string ; isHandledError: boolean ; messageType: CommandErrorResponse ; otp?: string ; payload: { data?: unknown ; message: string ; status: StatusCode } ; principalId?: string ; receiver: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; sender: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; tenantId?: string ; timestamp: number ; traceId?: string } | { contentEncoding: string ; contentType: string ; correlationId: string ; eventName?: string ; id: string ; messageType: CommandSuccessResponse ; otp?: string ; payload: unknown ; principalId?: string ; receiver: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; sender: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; tenantId?: string ; timestamp: number ; traceId?: string }>>

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:70

---

subscriptions

• Protected subscriptions: Map<string, SubscriptionStorageEntry>

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:78

---

traceProvider

• traceProvider: NodeTracerProvider

Inherited from

EventBridgeBaseClass.traceProvider

Defined in

core/EventBridge/EventBridgeBaseClass.impl.ts:19

---

writeStream

• Protected writeStream: Writable

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:62

Methods

destroy

▸ destroy(): Promise<void>

Shut down event bridge as gracefully as possible

Returns

Promise<void>

Implementation of

EventBridge.destroy

Overrides

EventBridgeBaseClass.destroy

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:382

---

emit

▸ emit<K>(eventName, parameter?): void

Type parameters

Name	Type
K	extends EventKey<{ eventbridge-connected: never ; eventbridge-connection-error: unknown ; eventbridge-disconnected: never ; eventbridge-error: unknown ; eventbridge-reconnecting: never }>

Parameters

Name	Type
eventName	K
parameter?	{ eventbridge-connected: never ; eventbridge-connection-error: unknown ; eventbridge-disconnected: never ; eventbridge-error: unknown ; eventbridge-reconnecting: never }[K]

Returns

void

Inherited from

EventBridgeBaseClass.emit

Defined in

core/types/GenericEventEmitter.ts:24

---

emitMessage

▸ emitMessage(message): Promise<Readonly<EBMessage>>

Emit a new message to event bridge to be delivered to receiver

Parameters

Name	Type	Description
message	Omit<EBMessage, "correlationId" | "id" | "timestamp">	EBMessage

Returns

Promise<Readonly<EBMessage>>

Implementation of

EventBridge.emitMessage

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:285

---

getTracer

▸ getTracer(): Tracer

Returns open telemetry tracer of this service

Returns

Tracer

Tracer

Inherited from

EventBridgeBaseClass.getTracer

Defined in

core/EventBridge/EventBridgeBaseClass.impl.ts:68

---

invoke

▸ invoke<T>(input, commandTimeout?): Promise<T>

Call a command of a service and return the result of this command

Type parameters

Name
T

Parameters

Name	Type	Description
input	Omit<{ contentEncoding: string ; contentType: string ; correlationId: string ; eventName?: string ; id: string ; messageType: Command ; otp?: string ; payload: { parameter: unknown ; payload: unknown } ; principalId?: string ; receiver: EBMessageAddress ; sender: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; tenantId?: string ; timestamp: number ; traceId?: string }, "messageType" | "correlationId" | "id" | "timestamp">	a partial command message
commandTimeout	number	the time to live (timeout) of the invocation

Returns

Promise<T>

Implementation of

EventBridge.invoke

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:326

---

isHealthy

▸ isHealthy(): Promise<boolean>

Indicates if the eventbridge is running and works correctly

Returns

Promise<boolean>

Implementation of

EventBridge.isHealthy

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:96

---

isReady

▸ isReady(): Promise<boolean>

Indicates if the eventbridge has been started and is connected to underlaying message broker

Returns

Promise<boolean>

Implementation of

EventBridge.isReady

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:92

---

off

▸ off<K>(eventName, fn): void

Type parameters

Name	Type
K	extends EventKey<{ eventbridge-connected: never ; eventbridge-connection-error: unknown ; eventbridge-disconnected: never ; eventbridge-error: unknown ; eventbridge-reconnecting: never }>

Parameters

Name	Type
eventName	K
fn	EventReceiver<{ eventbridge-connected: never ; eventbridge-connection-error: unknown ; eventbridge-disconnected: never ; eventbridge-error: unknown ; eventbridge-reconnecting: never }[K]>

Returns

void

Inherited from

EventBridgeBaseClass.off

Defined in

core/types/GenericEventEmitter.ts:20

---

on

▸ on<K>(eventName, fn): void

Type parameters

Name	Type
K	extends EventKey<{ eventbridge-connected: never ; eventbridge-connection-error: unknown ; eventbridge-disconnected: never ; eventbridge-error: unknown ; eventbridge-reconnecting: never }>

Parameters

Name	Type
eventName	K
fn	EventReceiver<{ eventbridge-connected: never ; eventbridge-connection-error: unknown ; eventbridge-disconnected: never ; eventbridge-error: unknown ; eventbridge-reconnecting: never }[K]>

Returns

void

Inherited from

EventBridgeBaseClass.on

Defined in

core/types/GenericEventEmitter.ts:16

---

registerCommand

▸ registerCommand(address, cb, metadata): Promise<string>

Register a service command and ensure that there is a queue for all incoming command requests.

Parameters

Name	Type	Description
address	EBMessageAddress	The service function address
cb	(message: { contentEncoding: string ; contentType: string ; correlationId: string ; eventName?: string ; id: string ; messageType: Command ; otp?: string ; payload: { parameter: unknown ; payload: unknown } ; principalId?: string ; receiver: EBMessageAddress ; sender: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; tenantId?: string ; timestamp: number ; traceId?: string }) => Promise<{ contentEncoding: "utf-8" ; contentType: "application/json" ; correlationId: string ; eventName?: string ; id: string ; isHandledError: boolean ; messageType: CommandErrorResponse ; otp?: string ; payload: { data?: unknown ; message: string ; status: StatusCode } ; principalId?: string ; receiver: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; sender: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; tenantId?: string ; timestamp: number ; traceId?: string } | { contentEncoding: string ; contentType: string ; correlationId: string ; eventName?: string ; id: string ; messageType: CommandSuccessResponse ; otp?: string ; payload: unknown ; principalId?: string ; receiver: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; sender: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; tenantId?: string ; timestamp: number ; traceId?: string }>	the function to call if a matching command message arrives
metadata	CommandDefinitionMetadataBase	-

Returns

Promise<string>

the id of command function queue

Implementation of

EventBridge.registerCommand

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:240

---

registerSubscription

▸ registerSubscription(subscription, cb): Promise<string>

Register a new subscription

Parameters

Name	Type	Description
subscription	Subscription	the subscription definition
cb	(message: EBMessage) => Promise<undefined | Omit<{ contentEncoding: string ; contentType: string ; correlationId?: string ; eventName: string ; id: string ; messageType: CustomMessage ; otp?: string ; payload?: unknown ; principalId?: string ; receiver?: EBMessageAddress ; sender: { serviceName: string; serviceVersion: string; serviceTarget: string; instanceId: string; } ; tenantId?: string ; timestamp: number ; traceId?: string }, "id" | "timestamp">>	the function to be called if a matching message arrives

Returns

Promise<string>

Implementation of

EventBridge.registerSubscription

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:265

---

removeAllListeners

▸ removeAllListeners(): void

Returns

void

Inherited from

EventBridgeBaseClass.removeAllListeners

Defined in

core/types/GenericEventEmitter.ts:28

---

start

▸ start(): Promise<void>

Start the eventbridge and connect to the underlaying message broker

Returns

Promise<void>

Implementation of

EventBridge.start

Overrides

EventBridgeBaseClass.start

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:100

---

startActiveSpan

▸ startActiveSpan<F>(name, opts, context?, fn): Promise<F>

Start a child span for opentelemetry tracking

Type parameters

Name
F

Parameters

Name	Type	Default value	Description
name	string	undefined	name of span
opts	SpanOptions	undefined	span options
context	undefined | Context	undefined	optional context
fn	(span: Span) => Promise<F>	undefined	function to be executed within the span

Returns

Promise<F>

return value of fn

Inherited from

EventBridgeBaseClass.startActiveSpan

Defined in

core/EventBridge/EventBridgeBaseClass.impl.ts:80

---

unregisterCommand

▸ unregisterCommand(address): Promise<void>

Unregister a service command

Parameters

Name	Type	Description
address	EBMessageAddress	The address (service name, version and command name) of the command to be de-registered

Returns

Promise<void>

Implementation of

EventBridge.unregisterCommand

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:260

---

unregisterSubscription

▸ unregisterSubscription(address): Promise<void>

Parameters

Name	Type
address	EBMessageAddress

Returns

Promise<void>

Implementation of

EventBridge.unregisterSubscription

Defined in

DefaultEventBridge/DefaultEventBridge.impl.ts:275

---

wrapInSpan

▸ wrapInSpan<F>(name, opts, fn, context?): Promise<F>

Start span for opentelemetry tracking on same level. The created span will not become the "active" span within opentelemetry!

This means during logging and similar the spanId of parent span is logged.

Use wrapInSpan for marking points in flow of one bigger function, but not to trace the program flow itself

Type parameters

Name
F

Parameters

Name	Type	Description
name	string	name of span
opts	SpanOptions	span options
fn	(span: Span) => Promise<F>	function te be executed in the span
context?	Context	span context

Returns

Promise<F>

return value of fn

Inherited from

EventBridgeBaseClass.wrapInSpan

Defined in

core/EventBridge/EventBridgeBaseClass.impl.ts:130