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     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  52     const hashId = chargingStation.stationInfo!.hashId
  53     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  54     const idTagsFile = getIdTagsFile(chargingStation.stationInfo!)!
  55     switch (distribution) {
  56       case IdTagDistribution.RANDOM:
  57         return this.getRandomIdTag(hashId, idTagsFile)
  58       case IdTagDistribution.ROUND_ROBIN:
  59         return this.getRoundRobinIdTag(hashId, idTagsFile)
  60       case IdTagDistribution.CONNECTOR_AFFINITY:
  61         return this.getConnectorAffinityIdTag(chargingStation, connectorId)
  62       default:
  63         return this.getRoundRobinIdTag(hashId, idTagsFile)
  64     }
  65   }
  66
  67   /**
  68    * Gets all idtags from the cache
  69    * Must be called after checking the cache is not an empty array
  70    *
  71    * @param file -
  72    * @returns
  73    */
  74   public getIdTags (file: string): string[] | undefined {
  75     if (!this.hasIdTagsCache(file)) {
  76       this.setIdTagsCache(file, this.getIdTagsFromFile(file))
  77     }
  78     return this.getIdTagsCache(file)
  79   }
  80
  81   public deleteIdTags (file: string): boolean {
  82     return this.deleteIdTagsCache(file) && this.deleteIdTagsCacheIndexes(file)
  83   }
  84
  85   private getRandomIdTag (hashId: string, file: string): string {
  86     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  87     const idTags = this.getIdTags(file)!
  88     const addressableKey = this.getIdTagsCacheIndexesAddressableKey(file, hashId)
  89     this.idTagsCachesAddressableIndexes.set(
  90       addressableKey,
  91       Math.floor(secureRandom() * idTags.length)
  92     )
  93     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  94     return idTags[this.idTagsCachesAddressableIndexes.get(addressableKey)!]
  95   }
  96
  97   private getRoundRobinIdTag (hashId: string, file: string): string {
  98     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  99     const idTags = this.getIdTags(file)!
 100     const addressableKey = this.getIdTagsCacheIndexesAddressableKey(file, hashId)
 101     const idTagIndex = this.idTagsCachesAddressableIndexes.get(addressableKey) ?? 0
 102     const idTag = idTags[idTagIndex]
 103     this.idTagsCachesAddressableIndexes.set(
 104       addressableKey,
 105       idTagIndex === idTags.length - 1 ? 0 : idTagIndex + 1
 106     )
 107     return idTag
 108   }
 109
 110   private getConnectorAffinityIdTag (chargingStation: ChargingStation, connectorId: number): string {
 111     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 112     const file = getIdTagsFile(chargingStation.stationInfo!)!
 113     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 114     const idTags = this.getIdTags(file)!
 115     const addressableKey = this.getIdTagsCacheIndexesAddressableKey(
 116       file,
 117       // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 118       chargingStation.stationInfo!.hashId
 119     )
 120     this.idTagsCachesAddressableIndexes.set(
 121       addressableKey,
 122       (chargingStation.index - 1 + (connectorId - 1)) % idTags.length
 123     )
 124     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 125     return idTags[this.idTagsCachesAddressableIndexes.get(addressableKey)!]
 126   }
 127
 128   private hasIdTagsCache (file: string): boolean {
 129     return this.idTagsCaches.has(file)
 130   }
 131
 132   private setIdTagsCache (file: string, idTags: string[]): Map<string, IdTagsCacheValueType> {
 133     return this.idTagsCaches.set(file, {
 134       idTags,
 135       idTagsFileWatcher: watchJsonFile(
 136         file,
 137         FileType.Authorization,
 138         this.logPrefix(file),
 139         undefined,
 140         (event, filename) => {
 141           if (isNotEmptyString(filename) && event === 'change') {
 142             try {
 143               logger.debug(
 144                 `${this.logPrefix(file)} ${FileType.Authorization} file have changed, reload`
 145               )
 146               this.deleteIdTags(file)
 147             } catch (error) {
 148               handleFileException(
 149                 file,
 150                 FileType.Authorization,
 151                 error as NodeJS.ErrnoException,
 152                 this.logPrefix(file),
 153                 {
 154                   throwError: false
 155                 }
 156               )
 157             }
 158           }
 159         }
 160       )
 161     })
 162   }
 163
 164   private getIdTagsCache (file: string): string[] | undefined {
 165     return this.idTagsCaches.get(file)?.idTags
 166   }
 167
 168   private deleteIdTagsCache (file: string): boolean {
 169     this.idTagsCaches.get(file)?.idTagsFileWatcher?.close()
 170     return this.idTagsCaches.delete(file)
 171   }
 172
 173   private deleteIdTagsCacheIndexes (file: string): boolean {
 174     const deleted: boolean[] = []
 175     for (const [key] of this.idTagsCachesAddressableIndexes) {
 176       if (key.startsWith(file)) {
 177         deleted.push(this.idTagsCachesAddressableIndexes.delete(key))
 178       }
 179     }
 180     return !deleted.some(value => !value)
 181   }
 182
 183   private getIdTagsCacheIndexesAddressableKey (prefix: string, uid: string): string {
 184     return `${prefix}${uid}`
 185   }
 186
 187   private getIdTagsFromFile (file: string): string[] {
 188     if (isNotEmptyString(file)) {
 189       try {
 190         return JSON.parse(readFileSync(file, 'utf8')) as string[]
 191       } catch (error) {
 192         handleFileException(
 193           file,
 194           FileType.Authorization,
 195           error as NodeJS.ErrnoException,
 196           this.logPrefix(file)
 197         )
 198       }
 199     }
 200     return []
 201   }
 202
 203   private readonly logPrefix = (file: string): string => {
 204     return logPrefix(` Id tags cache for id tags file '${file}' |`)
 205   }
 206 }