✨ Add Slack module

src/app.module.ts

@@ -33,6 +33,7 @@ import { ElasticSearchModule } from './providers/elasticsearch/elasticsearch.mod
 import { GeolocationModule } from './providers/geolocation/geolocation.module';
 import { MailModule } from './providers/mail/mail.module';
 import { PrismaModule } from './providers/prisma/prisma.module';
+import { SlackModule } from './providers/slack/slack.module';
 import { TasksModule } from './providers/tasks/tasks.module';
 
 @Module({
@@ -64,6 +65,7 @@ import { TasksModule } from './providers/tasks/tasks.module';
     AuditLogsModule,
     WebhooksModule,
     ElasticSearchModule,
+    SlackModule,
   ],
   providers: [
     {

src/config/configuration.interface.ts

@@ -84,4 +84,11 @@ export interface Configuration {
     deleteOldLogs: boolean;
     deleteOldLogsDays: number;
   };
+
+  slack: {
+    token: string;
+    slackApiUrl?: string;
+    rejectRateLimitedCalls?: boolean;
+    retries: number;
+  };
 }

src/config/configuration.ts

@@ -99,6 +99,12 @@ const configuration: Configuration = {
         : true,
     deleteOldLogsDays: int(process.env.TRACKING_DELETE_OLD_LOGS_DAYS, 90),
   },
+  slack: {
+    token: process.env.SLACK_TOKEN ?? '',
+    slackApiUrl: process.env.SLACK_API_URL,
+    rejectRateLimitedCalls: !!process.env.SLACK_REJECT_RATE_LIMITED_CALLS,
+    retries: int(process.env.SLACK_FAIL_RETRIES, 3),
+  },
 };
 
 const configFunction: ConfigFactory<Configuration> = () => configuration;

src/providers/slack/slack.module.ts

@@ -0,0 +1,10 @@
+import { Module } from '@nestjs/common';
+import { ConfigModule } from '@nestjs/config';
+import { SlackService } from './slack.service';
+
+@Module({
+  imports: [ConfigModule],
+  providers: [SlackService],
+  exports: [SlackService],
+})
+export class SlackModule {}

src/providers/slack/slack.service.ts

@@ -0,0 +1,43 @@
+import { Injectable, Logger } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import { ChatPostMessageArguments, WebClient } from '@slack/web-api';
+import PQueue from 'p-queue';
+import pRetry from 'p-retry';
+import { Configuration } from '../../config/configuration.interface';
+
+@Injectable()
+export class SlackService {
+  slack: WebClient;
+  private logger = new Logger(SlackService.name);
+  private queue = new PQueue({ concurrency: 1 });
+
+  constructor(private configService: ConfigService) {
+    const config = this.configService.get<Configuration['slack']>('slack');
+    if (config.token)
+      this.slack = new WebClient(config.token, {
+        slackApiUrl: config.slackApiUrl,
+        rejectRateLimitedCalls: config.rejectRateLimitedCalls,
+      });
+  }
+
+  send(options: ChatPostMessageArguments) {
+    this.queue
+      .add(() =>
+        pRetry(() => this.sendMessage(options), {
+          retries: this.configService.get<number>('slack.retries') ?? 3,
+          onFailedAttempt: (error) => {
+            this.logger.error(
+              `Message to ${options.channel} failed, retrying (${error.retriesLeft} attempts left)`,
+              error.name,
+            );
+          },
+        }),
+      )
+      .then(() => {})
+      .catch(() => {});
+  }
+
+  private async sendMessage(options: ChatPostMessageArguments) {
+    return this.slack.chat.postMessage(options);
+  }
+}