Implement getMany for groupLoader (#272)

Author: kibertoad

lib/AbstractFlatCache.ts

@@ -24,7 +24,7 @@ export abstract class AbstractFlatCache<LoadedValue, ResolveParams = undefined>
   }
 
   public getManyInMemoryOnly(keys: string[]): GetManyResult<LoadedValue> {
-    // ToDo no support for refresh, maybe later
+    // Note that it doesn't support preemptive refresh
     return this.inMemoryCache.getMany(keys)
   }
 
@@ -51,22 +51,22 @@ export abstract class AbstractFlatCache<LoadedValue, ResolveParams = undefined>
     return loadingPromise
   }
 
-  public getManyAsyncOnly(keys: string[], idResolver: IdResolver<LoadedValue>, resolveParams?: ResolveParams) {
-    // ToDo There is currently no deduplication. What would be a way to implement it without destroying the perf?..
-
+  public getManyAsyncOnly(
+    keys: string[],
+    idResolver: IdResolver<LoadedValue>,
+    resolveParams?: ResolveParams,
+  ): Promise<GetManyResult<LoadedValue>> {
+    // This doesn't support deduplication, and never might, as that would affect perf strongly. Maybe as an opt-in option in the future?
     const loadingPromise = this.resolveManyValues(keys, idResolver, resolveParams)
 
-    loadingPromise
-      .then((result) => {
-        for (let i = 0; i < result.resolvedValues.length; i++) {
-          const resolvedValue = result.resolvedValues[i]
-          const id = idResolver(resolvedValue)
-          this.inMemoryCache.set(id, resolvedValue)
-        }
-      })
-      .catch(() => {})
-
-    return loadingPromise
+    return loadingPromise.then((result) => {
+      for (let i = 0; i < result.resolvedValues.length; i++) {
+        const resolvedValue = result.resolvedValues[i]
+        const id = idResolver(resolvedValue)
+        this.inMemoryCache.set(id, resolvedValue)
+      }
+      return result
+    })
   }
 
   public get(key: string, resolveParams?: ResolveParams): Promise<LoadedValue | undefined | null> {
@@ -78,20 +78,22 @@ export abstract class AbstractFlatCache<LoadedValue, ResolveParams = undefined>
     return this.getAsyncOnly(key, resolveParams)
   }
 
-  public async getMany(
+  public getMany(
     keys: string[],
     idResolver: IdResolver<LoadedValue>,
     resolveParams?: ResolveParams,
   ): Promise<LoadedValue[]> {
     const inMemoryValues = this.getManyInMemoryOnly(keys)
     // everything is in memory, hurray
     if (inMemoryValues.unresolvedKeys.length === 0) {
-      return inMemoryValues.resolvedValues
+      return Promise.resolve(inMemoryValues.resolvedValues)
     }
 
-    const asyncRetrievedValues = await this.getManyAsyncOnly(inMemoryValues.unresolvedKeys, idResolver, resolveParams)
-
-    return [...inMemoryValues.resolvedValues, ...asyncRetrievedValues.resolvedValues]
+    return this.getManyAsyncOnly(inMemoryValues.unresolvedKeys, idResolver, resolveParams).then(
+      (asyncRetrievedValues) => {
+        return [...inMemoryValues.resolvedValues, ...asyncRetrievedValues.resolvedValues]
+      },
+    )
   }
 
   protected async resolveValue(key: string, _resolveParams?: ResolveParams): Promise<LoadedValue | undefined | null> {
@@ -112,7 +114,7 @@ export abstract class AbstractFlatCache<LoadedValue, ResolveParams = undefined>
     _resolveParams?: ResolveParams,
   ): Promise<GetManyResult<LoadedValue>> {
     if (this.asyncCache) {
-      return this.asyncCache.getManyCached(keys).catch((err) => {
+      return this.asyncCache.getMany(keys).catch((err) => {
         this.loadErrorHandler(err, keys.toString(), this.asyncCache!, this.logger)
         return {
           unresolvedKeys: keys,

lib/AbstractGroupCache.ts

@@ -1,6 +1,6 @@
 import { AbstractCache } from './AbstractCache'
-import type { GroupCache } from './types/DataSources'
-import type { SynchronousGroupCache } from './types/SyncDataSources'
+import type { GroupCache, IdResolver } from './types/DataSources'
+import type { GetManyResult, SynchronousGroupCache } from './types/SyncDataSources'
 import type { InMemoryGroupCacheConfiguration } from './memory/InMemoryGroupCache'
 import type { GroupNotificationPublisher } from './notifications/GroupNotificationPublisher'
 
@@ -47,6 +47,11 @@ export abstract class AbstractGroupCache<LoadedValue, ResolveParams = undefined>
     return this.inMemoryCache.getFromGroup(key, group)
   }
 
+  public getManyInMemoryOnly(keys: string[], group: string) {
+    // Note that it doesn't support preemptive refresh
+    return this.inMemoryCache.getManyFromGroup(keys, group)
+  }
+
   public getAsyncOnly(
     key: string,
     group: string,
@@ -75,6 +80,23 @@ export abstract class AbstractGroupCache<LoadedValue, ResolveParams = undefined>
     return loadingPromise
   }
 
+  public getManyAsyncOnly(
+    keys: string[],
+    group: string,
+    idResolver: IdResolver<LoadedValue>,
+    resolveParams?: ResolveParams,
+  ): Promise<GetManyResult<LoadedValue>> {
+    // This doesn't support deduplication, and never might, as that would affect perf strongly. Maybe as an opt-in option in the future?
+    return this.resolveManyGroupValues(keys, group, idResolver, resolveParams).then((result) => {
+      for (let i = 0; i < result.resolvedValues.length; i++) {
+        const resolvedValue = result.resolvedValues[i]
+        const id = idResolver(resolvedValue)
+        this.inMemoryCache.setForGroup(id, resolvedValue, group)
+      }
+      return result
+    })
+  }
+
   public get(key: string, group: string, resolveParams?: ResolveParams): Promise<LoadedValue | undefined | null> {
     const inMemoryValue = this.getInMemoryOnly(key, group, resolveParams)
     if (inMemoryValue !== undefined) {
@@ -84,6 +106,25 @@ export abstract class AbstractGroupCache<LoadedValue, ResolveParams = undefined>
     return this.getAsyncOnly(key, group, resolveParams)
   }
 
+  public getMany(
+    keys: string[],
+    group: string,
+    idResolver: IdResolver<LoadedValue>,
+    resolveParams?: ResolveParams,
+  ): Promise<LoadedValue[]> {
+    const inMemoryValues = this.getManyInMemoryOnly(keys, group)
+    // everything is in memory, hurray
+    if (inMemoryValues.unresolvedKeys.length === 0) {
+      return Promise.resolve(inMemoryValues.resolvedValues)
+    }
+
+    return this.getManyAsyncOnly(inMemoryValues.unresolvedKeys, group, idResolver, resolveParams).then(
+      (asyncRetrievedValues) => {
+        return [...inMemoryValues.resolvedValues, ...asyncRetrievedValues.resolvedValues]
+      },
+    )
+  }
+
   public async invalidateCacheFor(key: string, group: string) {
     this.inMemoryCache.deleteFromGroup(key, group)
     if (this.asyncCache) {
@@ -118,6 +159,27 @@ export abstract class AbstractGroupCache<LoadedValue, ResolveParams = undefined>
     return undefined
   }
 
+  protected async resolveManyGroupValues(
+    keys: string[],
+    group: string,
+    _idResolver: IdResolver<LoadedValue>,
+    _resolveParams?: ResolveParams,
+  ) {
+    if (this.asyncCache) {
+      return this.asyncCache.getManyFromGroup(keys, group).catch((err) => {
+        this.loadErrorHandler(err, keys.toString(), this.asyncCache!, this.logger)
+        return {
+          unresolvedKeys: keys,
+          resolvedValues: [],
+        }
+      })
+    }
+    return {
+      unresolvedKeys: keys,
+      resolvedValues: [],
+    }
+  }
+
   protected resolveGroupLoads(group: string) {
     const load = this.runningLoads.get(group)
     if (load) {

lib/GroupLoader.ts

@@ -1,8 +1,9 @@
-import type { GroupCache, GroupDataSource } from './types/DataSources'
+import type { GroupCache, GroupDataSource, IdResolver } from './types/DataSources'
 import type { LoaderConfig } from './Loader'
 import { AbstractGroupCache } from './AbstractGroupCache'
 import type { InMemoryGroupCacheConfiguration, InMemoryGroupCache } from './memory/InMemoryGroupCache'
 import type { GroupNotificationPublisher } from './notifications/GroupNotificationPublisher'
+import type { GetManyResult } from './types/SyncDataSources'
 
 export type GroupLoaderConfig<LoadedValue, LoaderParams = undefined> = LoaderConfig<
   LoadedValue,
@@ -79,6 +80,40 @@ export class GroupLoader<LoadedValue, LoaderParams = undefined> extends Abstract
     })
   }
 
+  protected override async resolveManyGroupValues(
+    keys: string[],
+    group: string,
+    idResolver: IdResolver<LoadedValue>,
+    loadParams?: LoaderParams,
+  ): Promise<GetManyResult<LoadedValue>> {
+    // load what is available from async cache
+    const cachedValues = await super.resolveManyGroupValues(keys, group, idResolver, loadParams)
+
+    // everything was cached, no need to load anything
+    if (cachedValues.unresolvedKeys.length === 0) {
+      return cachedValues
+    }
+
+    const loadValues = await this.loadManyFromLoaders(cachedValues.unresolvedKeys, group, loadParams)
+
+    if (this.asyncCache) {
+      for (let i = 0; i < loadValues.length; i++) {
+        const resolvedValue = loadValues[i]
+        const id = idResolver(resolvedValue)
+        await this.asyncCache.setForGroup(id, resolvedValue, group).catch((err) => {
+          this.cacheUpdateErrorHandler(err, id, this.asyncCache!, this.logger)
+        })
+      }
+    }
+
+    return {
+      resolvedValues: [...cachedValues.resolvedValues, ...loadValues],
+
+      // there actually may still be some unresolved keys, but we no longer know that
+      unresolvedKeys: [],
+    }
+  }
+
   private async loadFromLoaders(key: string, group: string, loadParams?: LoaderParams) {
     for (let index = 0; index < this.dataSources.length; index++) {
       const resolvedValue = await this.dataSources[index].getFromGroup(key, group, loadParams).catch((err) => {
@@ -104,4 +139,28 @@ export class GroupLoader<LoadedValue, LoaderParams = undefined> extends Abstract
 
     return undefined
   }
+
+  private async loadManyFromLoaders(keys: string[], group: string, loadParams?: LoaderParams) {
+    let lastResolvedValues
+    for (let index = 0; index < this.dataSources.length; index++) {
+      lastResolvedValues = await this.dataSources[index].getManyFromGroup(keys, group, loadParams).catch((err) => {
+        this.loadErrorHandler(err, keys.toString(), this.dataSources[index], this.logger)
+        if (this.throwIfLoadError) {
+          throw err
+        }
+        return [] as LoadedValue[]
+      })
+
+      if (lastResolvedValues.length === keys.length) {
+        return lastResolvedValues
+      }
+    }
+
+    if (this.throwIfUnresolved) {
+      throw new Error(`Failed to resolve value for some of the keys (group ${group}): ${keys.join(', ')}`)
+    }
+
+    // ToDo do we want to return results of a query that returned the most amount of entities?
+    return lastResolvedValues ?? []
+  }
 }

lib/Loader.ts

@@ -108,7 +108,7 @@ export class Loader<LoadedValue, LoaderParams = undefined> extends AbstractFlatC
     return undefined
   }
 
-  protected async resolveManyValues(
+  protected override async resolveManyValues(
     keys: string[],
     idResolver: IdResolver<LoadedValue>,
     loadParams?: LoaderParams,

lib/redis/RedisCache.ts

@@ -41,7 +41,7 @@ export class RedisCache<T> extends AbstractRedisCache<RedisCacheConfiguration, T
     })
   }
 
-  getManyCached(keys: string[]): Promise<GetManyResult<T>> {
+  getMany(keys: string[]): Promise<GetManyResult<T>> {
     const transformedKeys = keys.map((entry) => this.resolveKey(entry))
     const resolvedValues: T[] = []
     const unresolvedKeys: string[] = []

lib/redis/RedisExpirationTimeGroupDataSource.ts

@@ -11,4 +11,9 @@ export class RedisExpirationTimeGroupDataSource implements GroupDataSource<numbe
   getFromGroup(key: string, group: string): Promise<number | undefined> {
     return this.parentAsyncCache.getExpirationTimeFromGroup(key, group)
   }
+
+  /* c8 ignore next 3 */
+  getManyFromGroup(): Promise<number[]> {
+    throw new Error('Not supported')
+  }
 }

lib/redis/RedisGroupCache.ts

@@ -1,4 +1,4 @@
-import type { GroupCache, GroupCacheConfiguration, GroupDataSource } from '../types/DataSources'
+import type { GroupCache, GroupCacheConfiguration } from '../types/DataSources'
 import type Redis from 'ioredis'
 import { GET_OR_SET_ZERO_WITH_TTL, GET_OR_SET_ZERO_WITHOUT_TTL } from './lua'
 import { GroupLoader } from '../GroupLoader'
@@ -13,10 +13,7 @@ export interface RedisGroupCacheConfiguration extends RedisCacheConfiguration, G
   groupTtlInMsecs?: number
 }
 
-export class RedisGroupCache<T>
-  extends AbstractRedisCache<RedisGroupCacheConfiguration, T>
-  implements GroupCache<T>, GroupDataSource<T>
-{
+export class RedisGroupCache<T> extends AbstractRedisCache<RedisGroupCacheConfiguration, T> implements GroupCache<T> {
   public readonly expirationTimeLoadingGroupedOperation: GroupLoader<number>
   public ttlLeftBeforeRefreshInMsecs?: number
   name = 'Redis group cache'

lib/types/DataSources.ts

@@ -26,7 +26,7 @@ export interface Cache<LoadedValue> extends WriteCache<LoadedValue> {
   readonly ttlLeftBeforeRefreshInMsecs?: number
   readonly expirationTimeLoadingOperation: Loader<number>
   get: (key: string) => Promise<LoadedValue | undefined | null>
-  getManyCached: (keys: string[]) => Promise<GetManyResult<LoadedValue>>
+  getMany: (keys: string[]) => Promise<GetManyResult<LoadedValue>>
   getExpirationTime: (key: string) => Promise<number | undefined>
 }
 
@@ -56,6 +56,7 @@ export interface DataSource<LoadedValue, LoadParams = undefined> {
 
 export interface GroupDataSource<LoadedValue, LoadParams = undefined> {
   getFromGroup: (key: string, group: string, loadParams?: LoadParams) => Promise<LoadedValue | undefined | null>
+  getManyFromGroup: (keys: string[], group: string, loadParams?: LoadParams) => Promise<LoadedValue[]>
 
   name: string
 }