feat: lifecycle events for bot, svcs (#16)

Author: ssube

src/BaseService.ts

@@ -7,7 +7,7 @@ import * as uuid from 'uuid/v4';
 
 import { SchemaError } from 'src/error/SchemaError';
 import { ServiceModule } from 'src/module/ServiceModule';
-import { Service, ServiceDefinition } from 'src/Service';
+import { Service, ServiceDefinition, ServiceLifecycle } from 'src/Service';
 import { Clock } from 'src/utils/Clock';
 import { JsonPath } from 'src/utils/JsonPath';
 import { dictToMap } from 'src/utils/Map';
@@ -64,6 +64,10 @@ export abstract class BaseService<TData> implements Service {
     }
   }
 
+  public async notify(event: ServiceLifecycle): Promise<void> {
+    this.logger.debug({ event }, 'service notified of event');
+  }
+
   public abstract start(): Promise<void>;
   public abstract stop(): Promise<void>;
 

src/Bot.ts

@@ -13,7 +13,7 @@ import { checkFilter, Filter, FilterData, FilterValue } from 'src/filter/Filter'
 import { ContextFetchOptions, Listener, ListenerData } from 'src/listener/Listener';
 import { ServiceModule } from 'src/module/ServiceModule';
 import { Parser, ParserData } from 'src/parser/Parser';
-import { Service, ServiceDefinition } from 'src/Service';
+import { Service, ServiceDefinition, ServiceLifecycle } from 'src/Service';
 import { filterNil, mustFind } from 'src/utils';
 import { incrementServiceCounter } from 'src/utils/metrics/Service';
 import { StorageLogger, StorageLoggerOptions } from 'src/utils/StorageLogger';
@@ -88,6 +88,18 @@ export class Bot extends BaseService<BotData> implements Service {
     return this.storage;
   }
 
+  public async notify(event: ServiceLifecycle) {
+    await super.notify(event);
+    await this.services.notify(event);
+
+    switch (event) {
+      case ServiceLifecycle.Reset:
+        this.metrics.clear();
+        this.logger.info('metrics reset');
+        break;
+    }
+  }
+
   /**
    * Set up the async resources that cannot be created in the constructor: filters, controllers, parsers, etc
    */

src/Service.ts

@@ -8,6 +8,13 @@ export interface ServiceDefinition<TData = any> {
   data: TData;
 }
 
+export enum ServiceLifecycle {
+  Reload = 'reload',
+  Reset = 'reset',
+  Start = 'start',
+  Stop = 'stop',
+}
+
 export interface ServiceMetadata {
   /**
    * The service's unique id.
@@ -33,6 +40,7 @@ export interface ServiceMetadata {
 export interface Service extends ServiceMetadata {
   readonly id: string;
 
+  notify(event: ServiceLifecycle): Promise<void>;
   start(): Promise<void>;
   stop(): Promise<void>;
 }

src/index.ts

@@ -1,4 +1,4 @@
-import { Container, Module } from 'noicejs';
+import { Container, Logger, Module } from 'noicejs';
 import * as sourceMapSupport from 'source-map-support';
 import * as yargs from 'yargs-parser';
 
@@ -15,7 +15,8 @@ import { ServiceModule } from 'src/module/ServiceModule';
 import { TransformModule } from 'src/module/TransformModule';
 import { BunyanLogger } from 'src/utils/BunyanLogger';
 import { Schema } from 'src/utils/Schema';
-import { signal, SIGNAL_STOP } from 'src/utils/Signal';
+import { signal, SIGNAL_RELOAD, SIGNAL_RESET, SIGNAL_STOP } from 'src/utils/Signal';
+import { ServiceLifecycle } from './Service';
 
 // main arguments
 const MAIN_ARGS: yargs.Options = {
@@ -81,9 +82,26 @@ function createModules(botModule: BotModule, migrate: boolean) {
   return modules;
 }
 
-async function handleSignals(bot: Bot) {
+async function handleSignals(bot: Bot, logger: Logger) {
   await bot.start();
-  await signal(SIGNAL_STOP);
+  await bot.notify(ServiceLifecycle.Start);
+
+  const signals = [SIGNAL_RELOAD, SIGNAL_RESET, SIGNAL_STOP];
+  let s = await signal(...signals);
+  while (s !== SIGNAL_STOP) {
+    switch (s) {
+      case SIGNAL_RELOAD:
+        bot.notify(ServiceLifecycle.Reload);
+        break;
+      case SIGNAL_RESET:
+        bot.notify(ServiceLifecycle.Reset);
+        break;
+    }
+    s = await signal(...signals);
+  }
+
+  logger.info('stop signal');
+  await bot.notify(ServiceLifecycle.Stop);
   await bot.stop();
 }
 
@@ -116,7 +134,7 @@ async function main(argv: Array<string>): Promise<number> {
   botModule.setBot(bot);
 
   logger.info('starting bot');
-  await handleSignals(bot);
+  await handleSignals(bot, logger);
 
   return STATUS_SUCCESS;
 }

src/module/ServiceModule.ts

@@ -4,7 +4,7 @@ import { Container } from 'noicejs/Container';
 
 import { BotServiceOptions } from 'src/BotService';
 import { NotFoundError } from 'src/error/NotFoundError';
-import { Service, ServiceDefinition, ServiceMetadata } from 'src/Service';
+import { Service, ServiceDefinition, ServiceMetadata, ServiceLifecycle } from 'src/Service';
 import { mustGet } from 'src/utils/Map';
 
 /**
@@ -29,6 +29,12 @@ export class ServiceModule extends Module implements Service {
     return this.services.size;
   }
 
+  public async notify(event: ServiceLifecycle) {
+    for (const svc of this.services.values()) {
+      await svc.notify(event);
+    }
+  }
+
   public async start() {
     for (const svc of this.services.values()) {
       await svc.start();

src/utils/Signal.ts

@@ -1,13 +1,14 @@
-export const SIGNAL_RELOAD: Array<NodeJS.Signals> = ['SIGHUP'];
-export const SIGNAL_STOP: Array<NodeJS.Signals> = ['SIGINT', 'SIGTERM'];
+export const SIGNAL_RELOAD: NodeJS.Signals = 'SIGHUP';
+export const SIGNAL_RESET: NodeJS.Signals = 'SIGINT';
+export const SIGNAL_STOP: NodeJS.Signals = 'SIGTERM';
 
-export function signal(signals: Array<NodeJS.Signals>): Promise<void> {
+export function signal(...signals: Array<NodeJS.Signals>): Promise<NodeJS.Signals> {
   return new Promise((res, _) => {
-    function handler() {
-      for (const sig of signals) {
-        process.removeListener(sig, handler);
+    function handler(fired: NodeJS.Signals) {
+      for (const signal of signals) {
+        process.removeListener(signal, handler);
       }
-      res();
+      res(fired);
     }
 
     for (const sig of signals) {