PURISTA API / Modules / @purista/natsbridge
Module: @purista/natsbridge
Package for using a NATS broker as event bridge.
The event bridge supports brokers with and without JetStream enabled.
If JetStream is enabled, subscriptions which are marked as durable are persisted by using JetStream.
If JetStream is not available, subscription fall back to live-subscriptions without any persistence.
Example
import { NatsBridge } from '@purista/natsbridge'
// create and init our eventbridge
const eventBridge = new NatsBridge()
await eventBridge.start()Table of contents
Classes
Type Aliases
Variables
Functions
- getCommandSubscriptionTopic
- getDefaultNatsBridgeConfig
- getQueueGroupName
- getSubscriptionTopic
- getTopicName
Type Aliases
IncomingMessageFunction
Ƭ IncomingMessageFunction: (this: NatsBridge, error: NatsError | null, msg: Msg) => Promise<void>
Type declaration
▸ (this, error, msg): Promise<void>
Parameters
| Name | Type |
|---|---|
this | NatsBridge |
error | NatsError | null |
msg | Msg |
Returns
Promise<void>
Defined in
natsbridge/src/types/IncomingMessageFunction.ts:5
NatsBridgeConfig
Ƭ NatsBridgeConfig: Prettify<{ commandResponsePublishTwice: "always" | "eventOnly" | "eventAndError" | "never" ; defaultMessageExpiryInterval: number ; emptyTopicPartString: string ; maxMessages: number ; topicPrefix: string } & ConnectionOptions>
the configuration for the NATS event bridge
Defined in
natsbridge/src/types/NatsBridgeConfig.ts:6
Variables
puristaVersion
• Const puristaVersion: "1.11.0"
Defined in
Functions
getCommandSubscriptionTopic
▸ getCommandSubscriptionTopic(this, address): string
Parameters
| Name | Type |
|---|---|
this | NatsBridge |
address | EBMessageAddress |
Returns
string
Defined in
natsbridge/src/topic/getCommandSubscriptionTopic.impl.ts:8
getDefaultNatsBridgeConfig
▸ getDefaultNatsBridgeConfig(): Object
Returns
Object
| Name | Type | Description |
|---|---|---|
commandResponsePublishTwice | "always" | "eventOnly" | "eventAndError" | "never" | Indicates if a command response should be published a second time. If the command response gets published, it will be published to the regular topic pattern. If set to never, subscription might not get messages they are expecting because of the timing. If set to always, every command response is published. Because there might not be a consumer for every message, the broker will store the messages until the defaultMessageExpiryInterval is reached. This might result in a high ressource consumption of the broker. If set to eventOnly, only success responses which have a event name set, are published twice. There, we expect, that an event has at least one consumer subscription and the broker does not unnecessarily stores messages for a long time. Default ts eventOnly |
defaultMessageExpiryInterval | number | the message expiry interval in seconds Default ts 30 days in seconds |
emptyTopicPartString | string | The string which should be used in topics for parts, which are undefined Default ts __none__ |
maxMessages | number | maximum messages to run in parallel per subscription 10 means, each subscription can handle 10 calls at the same time Default ts 10 |
topicPrefix | string | the prefix for topic to prevent name collisions Default ts purista |
Defined in
natsbridge/src/getDefaultNatsBridgeConfig.ts:4
getQueueGroupName
▸ getQueueGroupName(prefix, address): string
Parameters
| Name | Type |
|---|---|
prefix | string |
address | EBMessageAddress |
Returns
string
Defined in
natsbridge/src/getQueueGroupName.impl.ts:3
getSubscriptionTopic
▸ getSubscriptionTopic(this, subscription): string
Parameters
| Name | Type |
|---|---|
this | NatsBridge |
subscription | Subscription |
Returns
string
Defined in
natsbridge/src/topic/getSubscriptionTopic.impl.ts:8
getTopicName
▸ getTopicName(this, message): string
Calculates the NATS topic name for a message which should be sent. Something like: purista/message_type/instance_id/sender_name/sender_version/sender_target/eventname/receiver_name/receiver_version/receiver_target
Parameters
| Name | Type | Description |
|---|---|---|
this | NatsBridge | - |
message | EBMessage | the message to send |
Returns
string
the NATS topic