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https://github.com/buka-lnc/npm.nestjs-kafka
NestJS module supporting multiple connections implemented using KafkaJS
https://github.com/buka-lnc/npm.nestjs-kafka
kafka kafka-module kafka-node kafka-nodejs kafkajs module nest nestjs node nodejs
Last synced: 2 months ago
JSON representation
NestJS module supporting multiple connections implemented using KafkaJS
- Host: GitHub
- URL: https://github.com/buka-lnc/npm.nestjs-kafka
- Owner: buka-lnc
- License: mit
- Created: 2024-01-16T05:55:00.000Z (11 months ago)
- Default Branch: main
- Last Pushed: 2024-04-20T14:06:17.000Z (8 months ago)
- Last Synced: 2024-10-09T11:26:29.210Z (2 months ago)
- Topics: kafka, kafka-module, kafka-node, kafka-nodejs, kafkajs, module, nest, nestjs, node, nodejs
- Language: TypeScript
- Homepage:
- Size: 33.2 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# @buka/nestjs-kafka
[npm]: https://www.npmjs.com/package/@buka/nestjs-kafka
[][npm]
[][npm]
[][npm]
[][npm]
[](https://codecov.io/gh/buka-lnc/npm.nestjs-kafka)
**Warning!!! This packages had be deprecated. Nestjs microservice has fully implemented this function. There is no reason to maintain this package.**
This is a nestJS module implemented using KafkaJS.
That support multiple connections and fits the coding style of nestjs.
## Usage
Import `KafkaModule.forRoot` to `AppModule`:
```typescript
// app.module.js
import { Module } from "@nestjs/common";
import { KafkaModule } from "@buka/nestjs-kafka";
@Module({
imports: [
KafkaModule.forRoot({
name: "my-kafka",
groupId: "my-group-id",
clientId: "my-client-id",
brokers: ["my_kafka_host:9092"],
}),
],
})
export class AppModule {}
```
### KafkaConsumer
Create a provider named `AppConsumer` that consume messages：
```typescript
// app.consumer.js
@Injectable()
@KafkaConsumer()
export class AppConsumer {
@KafkaConsume("my-topic")
async finishTask(@KafkaMessage() message: string): Promise {
// do something
console.log(message);
}
@KafkaConsume("other-topic", { json: true })
async finishTask(
@KafkaMessage() message: Record
): Promise {
// do something
console.log(message);
}
}
```
> `AppConsumer` and `AppService` can be merged into one provider, but writing them separately will make the code clearer.
Then, append `AppConsumer` to `AppModule`:
```typescript
import { Module } from "@nestjs/common";
import { AppConsumer } from "./app.consumer";
@Module({
imports: [
/* ... */
],
providers: [AppConsumer],
})
export class AppModule {}
```
### KafkaProducer
`KafkaProducer` will connect on module init and disconnect on module destroy.
To use this, import `KafkaModule.forProducer(options)` to `AppModule`:
```typescript
// app.module.js
import { Module } from "@nestjs/common";
import { KafkaModule, Partitioners } from "@buka/nestjs-kafka";
import AppService from "./app.service";
@Module({
imports: [
KafkaModule.forRoot({
name: "my-kafka",
groupId: "my-group-id",
clientId: "my-client-id",
brokers: ["my_kafka_host:9092"],
}),
KafkaModule.forProducer({
name: "my-kafka",
createPartitioner: Partitioners.LegacyPartitioner,
}),
],
provider: [AppService],
})
export class AppModule {}
```
> The `options` of `.forProducer` is exactly the same as [the `options` of `kafka.producer` in KafkaJS](https://kafka.js.org/docs/producing)。
Inject `KafkaProducer` to your `AppService`:
```typescript
// app.service.js
@Injectable()
export class AppService {
constructor(
@InjectKafkaProducer('my-kafka')
private readonly producer: KafkaProducer
) {}
async sendMessage() {
this.producer.send({
topic: 'kafka-topic'
messages: [{ value: 'Hello Kafka' }]
})
}
}
```
The `.send` function of `KafkaProducer` is exactly the same as [the `.send` function of KafkaJS](https://kafka.js.org/docs/producing#producing-messages)。
### KafkaService
Using the `KafkaService`, you can create `consumer` and `producer` like plain KafkaJS.
```typescript
// app.service.js
import { OnModuleDestroy, OnModuleInit } from "@nestjs/common";
import { Producer, ProducerRecord, RecordMetadata } from "kafkajs";
import { KafkaService } from "@buka/nestjs-kafka";
@Injectable()
export class AppService implements OnModuleInit, OnModuleDestroy {
producer!: Producer;
consumer!: Consumer;
constructor(private readonly kafka: KafkaService) {}
async onModuleInit(): Promise {
this.producer = this.kafka.producer();
await this.producer.connect();
this.consumer = this.kafka.consumer({
groupId: "my-group-id",
});
this.consumer.subscribe({ topic: "kafka-topic" });
this.consumer.run({
eachMessage: async (context) => {
// do somethings
},
});
}
async onModuleDestroy(): Promise {
await this.producer.disconnect();
await this.consumer.disconnect();
}
}
```
## Q&A
### `KafkaConsumer` not working with `CreateRequestContext` of `mikro-orm`
If you don't pay attention to the order of `CreateRequestContext` decorators,
you may have problems with any of other method decorators, not only `@buka/nestjs-kafka`.
```typescript
import { Injectable } from "@nestjs/common";
import { KafkaConsumer, KafkaConsume, KafkaMessage } from "@buka/nestjs-kafka";
import { CreateRequestContext } from "@mikro-orm/mysql";
// app.consumer.js
@Injectable()
@KafkaConsumer()
export class AppConsumer {
@CreateRequestContext()
// !! KafkaConsume decorator will not work !!
@KafkaConsume("my-topic")
async finishTask(@KafkaMessage() message: string): Promise {
console.log(message);
}
}
```
There are two solutions:
1. [recommend] written as two functions:
```typescript
@Injectable()
@KafkaConsumer()
export class AppConsumer {
@KafkaConsume("my-topic")
async consumeMessage(@KafkaMessage() message: string): Promise {
// ... filter and format message
this.finishTask(JSON.parse(message))
}
@CreateRequestContext()
async finishTask(task: Task): Promise {
// do something
console.log(task);
}
```
1. Pay attention to the order of `CreateRequestContext`:
```typescript
@Injectable()
@KafkaConsumer()
export class AppConsumer {
@KafkaConsume("my-topic")
// use CreateRequestContext as the last decorator
@CreateRequestContext()
async finishTask(@KafkaMessage() message: string): Promise {
// do something
console.log(message);
}
}
```