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| 1 | +import { setTimeout } from 'node:timers/promises' |
| 2 | +import { InternalError, stringValueSerializer } from '@lokalise/node-core' |
| 3 | +import { |
| 4 | + type ConsumeOptions, |
| 5 | + Consumer, |
| 6 | + type ConsumerOptions, |
| 7 | + type Message, |
| 8 | + type MessagesStream, |
| 9 | + jsonDeserializer, |
| 10 | + stringDeserializer, |
| 11 | +} from '@platformatic/kafka' |
| 12 | +import { AbstractKafkaService, type BaseKafkaOptions } from './AbstractKafkaService.ts' |
| 13 | +import { KafkaHandlerContainer } from './handler-container/KafkaHandlerContainer.js' |
| 14 | +import type { KafkaHandlerRouting } from './handler-container/KafkaHandlerRoutingBuilder.js' |
| 15 | +import type { KafkaHandler } from './handler-container/index.js' |
| 16 | +import type { KafkaDependencies, TopicConfig } from './types.ts' |
| 17 | + |
| 18 | +export type KafkaConsumerOptions<TopicsConfig extends TopicConfig[]> = BaseKafkaOptions & |
| 19 | + Omit< |
| 20 | + ConsumerOptions<string, object, string, object>, |
| 21 | + 'deserializers' | 'autocommit' | 'bootstrapBrokers' |
| 22 | + > & |
| 23 | + Omit<ConsumeOptions<string, object, string, object>, 'topics'> & { |
| 24 | + handlers: KafkaHandlerRouting<TopicsConfig> |
| 25 | + } |
| 26 | + |
| 27 | +/* |
| 28 | +TODO: Proper retry mechanism + DLQ -> https://lokalise.atlassian.net/browse/EDEXP-498 |
| 29 | +In the meantime, we will retry in memory up to 3 times |
| 30 | + */ |
| 31 | +const MAX_IN_MEMORY_RETRIES = 3 |
| 32 | + |
| 33 | +export abstract class AbstractKafkaConsumer< |
| 34 | + TopicsConfig extends TopicConfig[], |
| 35 | +> extends AbstractKafkaService<TopicsConfig, KafkaConsumerOptions<TopicsConfig>> { |
| 36 | + private readonly consumer: Consumer<string, object, string, object> |
| 37 | + private consumerStream?: MessagesStream<string, object, string, object> |
| 38 | + |
| 39 | + private readonly handlerContainer: KafkaHandlerContainer<TopicsConfig> |
| 40 | + |
| 41 | + constructor(dependencies: KafkaDependencies, options: KafkaConsumerOptions<TopicsConfig>) { |
| 42 | + super(dependencies, options) |
| 43 | + |
| 44 | + this.handlerContainer = new KafkaHandlerContainer<TopicsConfig>( |
| 45 | + options.handlers, |
| 46 | + options.messageTypeField, |
| 47 | + ) |
| 48 | + |
| 49 | + this.consumer = new Consumer({ |
| 50 | + ...this.options.kafka, |
| 51 | + ...this.options, |
| 52 | + autocommit: false, // Handling commits manually |
| 53 | + deserializers: { |
| 54 | + key: stringDeserializer, |
| 55 | + value: jsonDeserializer, |
| 56 | + headerKey: stringDeserializer, |
| 57 | + headerValue: jsonDeserializer, |
| 58 | + }, |
| 59 | + }) |
| 60 | + } |
| 61 | + |
| 62 | + async init(): Promise<void> { |
| 63 | + if (this.consumerStream) return Promise.resolve() |
| 64 | + const topics = this.handlerContainer.topics |
| 65 | + if (topics.length === 0) throw new Error('At least one topic must be defined') |
| 66 | + |
| 67 | + try { |
| 68 | + const { handlers, ...consumeOptions } = this.options // Handlers cannot be passed to consume method |
| 69 | + this.consumerStream = await this.consumer.consume({ ...consumeOptions, topics }) |
| 70 | + } catch (error) { |
| 71 | + throw new InternalError({ |
| 72 | + message: 'Consumer init failed', |
| 73 | + errorCode: 'KAFKA_CONSUMER_INIT_ERROR', |
| 74 | + cause: error, |
| 75 | + }) |
| 76 | + } |
| 77 | + |
| 78 | + this.consumerStream.on('data', (message) => this.consume(message)) |
| 79 | + this.consumerStream.on('error', (error) => this.handlerError(error)) |
| 80 | + } |
| 81 | + |
| 82 | + async close(): Promise<void> { |
| 83 | + if (!this.consumerStream) return Promise.resolve() |
| 84 | + |
| 85 | + await new Promise((done) => this.consumerStream?.close(done)) |
| 86 | + this.consumerStream = undefined |
| 87 | + await this.consumer.close() |
| 88 | + } |
| 89 | + |
| 90 | + /* |
| 91 | + TODO: https://lokalise.atlassian.net/browse/EDEXP-493 |
| 92 | + - Improve logging with logger child on constructor + add request context? |
| 93 | + - Message logging |
| 94 | + - Observability |
| 95 | + */ |
| 96 | + |
| 97 | + private async consume(message: Message<string, object, string, object>): Promise<void> { |
| 98 | + const handler = this.handlerContainer.resolveHandler(message.topic, message.value) |
| 99 | + // if there is no handler for the message, we ignore it (simulating subscription) |
| 100 | + if (!handler) return message.commit() |
| 101 | + |
| 102 | + const parseResult = handler.schema.safeParse(message.value) |
| 103 | + if (!parseResult.success) { |
| 104 | + this.handlerError(parseResult.error, { |
| 105 | + topic: message.topic, |
| 106 | + message: stringValueSerializer(message.value), |
| 107 | + }) |
| 108 | + this.handleMessageProcessed({ |
| 109 | + topic: message.topic, |
| 110 | + message: message.value, |
| 111 | + processingResult: { status: 'error', errorReason: 'invalidMessage' }, |
| 112 | + }) |
| 113 | + |
| 114 | + return message.commit() |
| 115 | + } |
| 116 | + |
| 117 | + const validatedMessage = parseResult.data |
| 118 | + |
| 119 | + let retries = 0 |
| 120 | + let consumed = false |
| 121 | + do { |
| 122 | + // exponential backoff -> 2^(retry-1) |
| 123 | + if (retries > 0) await setTimeout(Math.pow(2, retries - 1)) |
| 124 | + |
| 125 | + consumed = await this.tryToConsume({ ...message, value: validatedMessage }, handler.handler) |
| 126 | + if (consumed) break |
| 127 | + |
| 128 | + retries++ |
| 129 | + } while (retries < MAX_IN_MEMORY_RETRIES) |
| 130 | + |
| 131 | + if (consumed) { |
| 132 | + this.handleMessageProcessed({ |
| 133 | + topic: message.topic, |
| 134 | + message: validatedMessage, |
| 135 | + processingResult: { status: 'consumed' }, |
| 136 | + }) |
| 137 | + } else { |
| 138 | + this.handleMessageProcessed({ |
| 139 | + topic: message.topic, |
| 140 | + message: validatedMessage, |
| 141 | + processingResult: { status: 'error', errorReason: 'handlerError' }, |
| 142 | + }) |
| 143 | + } |
| 144 | + |
| 145 | + return message.commit() |
| 146 | + } |
| 147 | + |
| 148 | + private async tryToConsume<MessageValue extends object>( |
| 149 | + message: Message<string, MessageValue, string, object>, |
| 150 | + handler: KafkaHandler<MessageValue>, |
| 151 | + ): Promise<boolean> { |
| 152 | + try { |
| 153 | + await handler(message) |
| 154 | + return true |
| 155 | + } catch (error) { |
| 156 | + this.handlerError(error, { |
| 157 | + topic: message.topic, |
| 158 | + message: stringValueSerializer(message.value), |
| 159 | + }) |
| 160 | + } |
| 161 | + |
| 162 | + return false |
| 163 | + } |
| 164 | +} |
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