src/charging-station/IdTagsCache.ts

   1 import { type FSWatcher, readFileSync } from 'node:fs'
   2
   3 import type { ChargingStation } from './ChargingStation.js'
   4 import { getIdTagsFile } from './Helpers.js'
   5 import { FileType, IdTagDistribution } from '../types/index.js'
   6 import {
   7   handleFileException,
   8   isNotEmptyString,
   9   logPrefix,
  10   logger,
  11   secureRandom,
  12   watchJsonFile
  13 } from '../utils/index.js'
  14
  15 interface 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     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  53     const idTagsFile = getIdTagsFile(chargingStation.stationInfo)!
  54     switch (distribution) {
  55       case IdTagDistribution.RANDOM:
  56         return this.getRandomIdTag(hashId, idTagsFile)
  57       case IdTagDistribution.ROUND_ROBIN:
  58         return this.getRoundRobinIdTag(hashId, idTagsFile)
  59       case IdTagDistribution.CONNECTOR_AFFINITY:
  60         return this.getConnectorAffinityIdTag(chargingStation, connectorId)
  61       default:
  62         return this.getRoundRobinIdTag(hashId, idTagsFile)
  63     }
  64   }
  65
  66   /**
  67    * Gets all idtags from the cache
  68    * Must be called after checking the cache is not an empty array
  69    *
  70    * @param file -
  71    * @returns
  72    */
  73   public getIdTags (file: string): string[] | undefined {
  74     if (!this.hasIdTagsCache(file)) {
  75       this.setIdTagsCache(file, this.getIdTagsFromFile(file))
  76     }
  77     return this.getIdTagsCache(file)
  78   }
  79
  80   public deleteIdTags (file: string): boolean {
  81     return this.deleteIdTagsCache(file) && this.deleteIdTagsCacheIndexes(file)
  82   }
  83
  84   private getRandomIdTag (hashId: string, file: string): string {
  85     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  86     const idTags = this.getIdTags(file)!
  87     const addressableKey = this.getIdTagsCacheIndexesAddressableKey(file, hashId)
  88     this.idTagsCachesAddressableIndexes.set(
  89       addressableKey,
  90       Math.floor(secureRandom() * idTags.length)
  91     )
  92     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  93     return idTags[this.idTagsCachesAddressableIndexes.get(addressableKey)!]
  94   }
  95
  96   private getRoundRobinIdTag (hashId: string, file: string): string {
  97     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  98     const idTags = this.getIdTags(file)!
  99     const addressableKey = this.getIdTagsCacheIndexesAddressableKey(file, hashId)
 100     const idTagIndex = this.idTagsCachesAddressableIndexes.get(addressableKey) ?? 0
 101     const idTag = idTags[idTagIndex]
 102     this.idTagsCachesAddressableIndexes.set(
 103       addressableKey,
 104       idTagIndex === idTags.length - 1 ? 0 : idTagIndex + 1
 105     )
 106     return idTag
 107   }
 108
 109   private getConnectorAffinityIdTag (chargingStation: ChargingStation, connectorId: number): string {
 110     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 111     const file = getIdTagsFile(chargingStation.stationInfo)!
 112     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 113     const idTags = this.getIdTags(file)!
 114     const addressableKey = this.getIdTagsCacheIndexesAddressableKey(
 115       file,
 116       chargingStation.stationInfo.hashId
 117     )
 118     this.idTagsCachesAddressableIndexes.set(
 119       addressableKey,
 120       (chargingStation.index - 1 + (connectorId - 1)) % idTags.length
 121     )
 122     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 123     return idTags[this.idTagsCachesAddressableIndexes.get(addressableKey)!]
 124   }
 125
 126   private hasIdTagsCache (file: string): boolean {
 127     return this.idTagsCaches.has(file)
 128   }
 129
 130   private setIdTagsCache (file: string, idTags: string[]): Map<string, IdTagsCacheValueType> {
 131     return this.idTagsCaches.set(file, {
 132       idTags,
 133       idTagsFileWatcher: watchJsonFile(
 134         file,
 135         FileType.Authorization,
 136         this.logPrefix(file),
 137         undefined,
 138         (event, filename) => {
 139           if (isNotEmptyString(filename) && event === 'change') {
 140             try {
 141               logger.debug(
 142                 `${this.logPrefix(file)} ${FileType.Authorization} file have changed, reload`
 143               )
 144               this.deleteIdTagsCache(file)
 145               this.deleteIdTagsCacheIndexes(file)
 146             } catch (error) {
 147               handleFileException(
 148                 file,
 149                 FileType.Authorization,
 150                 error as NodeJS.ErrnoException,
 151                 this.logPrefix(file),
 152                 {
 153                   throwError: false
 154                 }
 155               )
 156             }
 157           }
 158         }
 159       )
 160     })
 161   }
 162
 163   private getIdTagsCache (file: string): string[] | undefined {
 164     return this.idTagsCaches.get(file)?.idTags
 165   }
 166
 167   private deleteIdTagsCache (file: string): boolean {
 168     this.idTagsCaches.get(file)?.idTagsFileWatcher?.close()
 169     return this.idTagsCaches.delete(file)
 170   }
 171
 172   private deleteIdTagsCacheIndexes (file: string): boolean {
 173     const deleted: boolean[] = []
 174     for (const [key] of this.idTagsCachesAddressableIndexes) {
 175       if (key.startsWith(file)) {
 176         deleted.push(this.idTagsCachesAddressableIndexes.delete(key))
 177       }
 178     }
 179     return !deleted.some((value) => !value)
 180   }
 181
 182   private getIdTagsCacheIndexesAddressableKey (prefix: string, uid: string): string {
 183     return `${prefix}${uid}`
 184   }
 185
 186   private getIdTagsFromFile (file: string): string[] {
 187     if (isNotEmptyString(file)) {
 188       try {
 189         return JSON.parse(readFileSync(file, 'utf8')) as string[]
 190       } catch (error) {
 191         handleFileException(
 192           file,
 193           FileType.Authorization,
 194           error as NodeJS.ErrnoException,
 195           this.logPrefix(file)
 196         )
 197       }
 198     }
 199     return []
 200   }
 201
 202   private readonly logPrefix = (file: string): string => {
 203     return logPrefix(` Id tags cache for id tags file '${file}' |`)
 204   }
 205 }