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| import { Observable } from 'rxjs';
import {
CONNECT_EVENT,
ERROR_EVENT,
MESSAGE_EVENT,
NO_PATTERN_MESSAGE,
REDIS_DEFAULT_URL,
} from '../constants';
import {
ClientOpts,
RedisClient,
RetryStrategyOptions,
} from '../external/redis.interface';
import { CustomTransportStrategy, PacketId, ReadPacket } from '../interfaces';
import {
MicroserviceOptions,
RedisOptions,
} from '../interfaces/microservice-configuration.interface';
import { Server } from './server';
let redisPackage: any = {};
export class ServerRedis extends Server implements CustomTransportStrategy {
private readonly url: string;
private subClient: RedisClient;
private pubClient: RedisClient;
private isExplicitlyTerminated = false;
constructor(private readonly options: MicroserviceOptions['options']) {
super();
this.url =
this.getOptionsProp<RedisOptions>(this.options, 'url') ||
REDIS_DEFAULT_URL;
redisPackage = this.loadPackage('redis', ServerRedis.name);
}
public listen(callback: () => void) {
this.subClient = this.createRedisClient();
this.pubClient = this.createRedisClient();
this.handleError(this.pubClient);
this.handleError(this.subClient);
this.start(callback);
}
public start(callback?: () => void) {
this.bindEvents(this.subClient, this.pubClient);
this.subClient.on(CONNECT_EVENT, callback);
}
public bindEvents(subClient: RedisClient, pubClient: RedisClient) {
subClient.on(MESSAGE_EVENT, this.getMessageHandler(pubClient).bind(this));
const subscribePatterns = Object.keys(this.messageHandlers);
subscribePatterns.forEach(pattern =>
subClient.subscribe(this.getAckQueueName(pattern)),
);
}
public close() {
this.isExplicitlyTerminated = true;
this.pubClient && this.pubClient.quit();
this.subClient && this.subClient.quit();
}
public createRedisClient(): RedisClient {
return redisPackage.createClient({
...this.getClientOptions(),
url: this.url,
});
}
public getMessageHandler(pub: RedisClient) {
return async (channel, buffer) => this.handleMessage(channel, buffer, pub);
}
public async handleMessage(channel, buffer: string | any, pub: RedisClient) {
const packet = this.deserialize(buffer);
const pattern = channel.replace(/_ack$/, '');
const publish = this.getPublisher(pub, pattern, packet.id);
const status = 'error';
if (!this.messageHandlers[pattern]) {
return publish({ id: packet.id, status, err: NO_PATTERN_MESSAGE });
}
const handler = this.messageHandlers[pattern];
const response$ = this.transformToObservable(
await handler(packet.data),
) as Observable<any>;
response$ && this.send(response$, publish);
}
public getPublisher(pub: RedisClient, pattern: any, id: string) {
return response =>
pub.publish(
this.getResQueueName(pattern),
JSON.stringify(Object.assign(response, { id })),
);
}
public deserialize(content): ReadPacket & PacketId {
try {
return JSON.parse(content);
} catch (e) {
return content;
}
}
public getAckQueueName(pattern: string): string {
return `${pattern}_ack`;
}
public getResQueueName(pattern: string): string {
return `${pattern}_res`;
}
public handleError(stream) {
stream.on(ERROR_EVENT, err => this.logger.error(err));
}
public getClientOptions(): Partial<ClientOpts> {
const retry_strategy = options => this.createRetryStrategy(options);
return {
retry_strategy,
};
}
public createRetryStrategy(
options: RetryStrategyOptions,
): undefined | number | void {
if (options.error && (options.error as any).code === 'ECONNREFUSED') {
return this.logger.error(`Error ECONNREFUSED: ${this.url}`);
}
if (
this.isExplicitlyTerminated ||
!this.getOptionsProp<RedisOptions>(this.options, 'retryAttempts') ||
options.attempt >
this.getOptionsProp<RedisOptions>(this.options, 'retryAttempts')
) {
return undefined;
}
return this.getOptionsProp<RedisOptions>(this.options, 'retryDelay') || 0;
}
}
|