src/charging-station/IdTagsCache.ts

   1 import { type FSWatcher, readFileSync } from 'node:fs';
   2
   3 import type { ChargingStation } from './ChargingStation';
   4 import { getIdTagsFile } from './ChargingStationUtils';
   5 import { FileType, IdTagDistribution } from '../types';
   6 import {
   7   handleFileException,
   8   isNotEmptyString,
   9   logPrefix,
  10   logger,
  11   secureRandom,
  12   watchJsonFile,
  13 } from '../utils';
  14
  15 type IdTagsCacheValueType = {
  16   idTags: string[];
  17   idTagsFileWatcher: FSWatcher | undefined;
  18 };
  19
  20 export class IdTagsCache {
  21   private static instance: IdTagsCache | null = null;
  22   private readonly idTagsCaches: Map<string, IdTagsCacheValueType>;
  23   private readonly idTagsCachesAddressableIndexes: Map<string, number>;
  24
  25   private constructor() {
  26     this.idTagsCaches = new Map<string, IdTagsCacheValueType>();
  27     this.idTagsCachesAddressableIndexes = new Map<string, number>();
  28   }
  29
  30   public static getInstance(): IdTagsCache {
  31     if (IdTagsCache.instance === null) {
  32       IdTagsCache.instance = new IdTagsCache();
  33     }
  34     return IdTagsCache.instance;
  35   }
  36
  37   /**
  38    * Gets one idtag from the cache given the distribution
  39    * Must be called after checking the cache is not an empty array
  40    *
  41    * @param distribution -
  42    * @param chargingStation -
  43    * @param connectorId -
  44    * @returns
  45    */
  46   public getIdTag(
  47     distribution: IdTagDistribution,
  48     chargingStation: ChargingStation,
  49     connectorId: number
  50   ): string {
  51     const hashId = chargingStation.stationInfo.hashId;
  52     const idTagsFile = getIdTagsFile(chargingStation.stationInfo);
  53     switch (distribution) {
  54       case IdTagDistribution.RANDOM:
  55         return this.getRandomIdTag(hashId, idTagsFile);
  56       case IdTagDistribution.ROUND_ROBIN:
  57         return this.getRoundRobinIdTag(hashId, idTagsFile);
  58       case IdTagDistribution.CONNECTOR_AFFINITY:
  59         return this.getConnectorAffinityIdTag(chargingStation, connectorId);
  60       default:
  61         return this.getRoundRobinIdTag(hashId, idTagsFile);
  62     }
  63   }
  64
  65   /**
  66    * Gets all idtags from the cache
  67    * Must be called after checking the cache is not an empty array
  68    *
  69    * @param file -
  70    * @returns
  71    */
  72   public getIdTags(file: string): string[] | undefined {
  73     if (this.hasIdTagsCache(file) === false) {
  74       this.setIdTagsCache(file, this.getIdTagsFromFile(file));
  75     }
  76     return this.getIdTagsCache(file);
  77   }
  78
  79   public deleteIdTags(file: string): boolean {
  80     return this.deleteIdTagsCache(file) && this.deleteIdTagsCacheIndexes(file);
  81   }
  82
  83   private getRandomIdTag(hashId: string, file: string): string {
  84     const idTags = this.getIdTags(file);
  85     const addressableKey = this.getIdTagsCacheIndexesAddressableKey(file, hashId);
  86     this.idTagsCachesAddressableIndexes.set(
  87       addressableKey,
  88       Math.floor(secureRandom() * idTags.length)
  89     );
  90     return idTags[this.idTagsCachesAddressableIndexes.get(addressableKey)];
  91   }
  92
  93   private getRoundRobinIdTag(hashId: string, file: string): string {
  94     const idTags = this.getIdTags(file);
  95     const addressableKey = this.getIdTagsCacheIndexesAddressableKey(file, hashId);
  96     const idTagIndex = this.idTagsCachesAddressableIndexes.get(addressableKey) ?? 0;
  97     const idTag = idTags[idTagIndex];
  98     this.idTagsCachesAddressableIndexes.set(
  99       addressableKey,
 100       idTagIndex === idTags.length - 1 ? 0 : idTagIndex + 1
 101     );
 102     return idTag;
 103   }
 104
 105   private getConnectorAffinityIdTag(chargingStation: ChargingStation, connectorId: number): string {
 106     const file = getIdTagsFile(chargingStation.stationInfo);
 107     const idTags = this.getIdTags(file);
 108     const addressableKey = this.getIdTagsCacheIndexesAddressableKey(
 109       file,
 110       chargingStation.stationInfo.hashId
 111     );
 112     this.idTagsCachesAddressableIndexes.set(
 113       addressableKey,
 114       (chargingStation.index - 1 + (connectorId - 1)) % idTags.length
 115     );
 116     return idTags[this.idTagsCachesAddressableIndexes.get(addressableKey)];
 117   }
 118
 119   private hasIdTagsCache(file: string): boolean {
 120     return this.idTagsCaches.has(file);
 121   }
 122
 123   private setIdTagsCache(file: string, idTags: string[]) {
 124     return this.idTagsCaches.set(file, {
 125       idTags,
 126       idTagsFileWatcher: watchJsonFile(
 127         file,
 128         FileType.Authorization,
 129         this.logPrefix(file),
 130         undefined,
 131         (event, filename) => {
 132           if (isNotEmptyString(filename) && event === 'change') {
 133             try {
 134               logger.debug(
 135                 `${this.logPrefix(file)} ${FileType.Authorization} file have changed, reload`
 136               );
 137               this.deleteIdTagsCache(file);
 138               this.deleteIdTagsCacheIndexes(file);
 139             } catch (error) {
 140               handleFileException(
 141                 file,
 142                 FileType.Authorization,
 143                 error as NodeJS.ErrnoException,
 144                 this.logPrefix(file),
 145                 {
 146                   throwError: false,
 147                 }
 148               );
 149             }
 150           }
 151         }
 152       ),
 153     });
 154   }
 155
 156   private getIdTagsCache(file: string): string[] | undefined {
 157     return this.idTagsCaches.get(file)?.idTags;
 158   }
 159
 160   private deleteIdTagsCache(file: string): boolean {
 161     this.idTagsCaches.get(file)?.idTagsFileWatcher?.close();
 162     return this.idTagsCaches.delete(file);
 163   }
 164
 165   private deleteIdTagsCacheIndexes(file: string): boolean {
 166     let deleted: boolean[];
 167     for (const [key] of this.idTagsCachesAddressableIndexes) {
 168       if (key.startsWith(file)) {
 169         deleted.push(this.idTagsCachesAddressableIndexes.delete(key));
 170       }
 171     }
 172     return !deleted.some((value) => value === false);
 173   }
 174
 175   private getIdTagsCacheIndexesAddressableKey(prefix: string, uid: string): string {
 176     return `${prefix}${uid}`;
 177   }
 178
 179   private getIdTagsFromFile(file: string): string[] {
 180     if (isNotEmptyString(file)) {
 181       try {
 182         return JSON.parse(readFileSync(file, 'utf8')) as string[];
 183       } catch (error) {
 184         handleFileException(
 185           file,
 186           FileType.Authorization,
 187           error as NodeJS.ErrnoException,
 188           this.logPrefix(file)
 189         );
 190       }
 191     }
 192     return [];
 193   }
 194
 195   private logPrefix = (file: string): string => {
 196     return logPrefix(` Id tags cache for id tags file '${file}' |`);
 197   };
 198 }