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Diffstat (limited to 'packages/backend/src/misc/cache.ts')
| -rw-r--r-- | packages/backend/src/misc/cache.ts | 311 |
1 files changed, 0 insertions, 311 deletions
diff --git a/packages/backend/src/misc/cache.ts b/packages/backend/src/misc/cache.ts index 0a1cf6adb4..932c0b409a 100644 --- a/packages/backend/src/misc/cache.ts +++ b/packages/backend/src/misc/cache.ts @@ -422,314 +422,3 @@ export class MemorySingleCache<T> { return value; } } - -// TODO move to separate file - -export interface QuantumKVOpts<T> { - /** - * Memory cache lifetime in milliseconds. - */ - lifetime: number; - - /** - * Callback to fetch the value for a key that wasn't found in the cache. - * May be synchronous or async. - */ - fetcher: (key: string, cache: QuantumKVCache<T>) => T | Promise<T>; - - /** - * Optional callback when a value is created or changed in the cache, either locally or elsewhere in the cluster. - * This is called *after* the cache state is updated. - * May be synchronous or async. - */ - onSet?: (key: string, cache: QuantumKVCache<T>) => void | Promise<void>; - - /** - * Optional callback when a value is deleted from the cache, either locally or elsewhere in the cluster. - * This is called *after* the cache state is updated. - * May be synchronous or async. - */ - onDelete?: (key: string, cache: QuantumKVCache<T>) => void | Promise<void>; -} - -/** - * QuantumKVCache is a lifetime-bounded memory cache (like MemoryKVCache) with automatic cross-cluster synchronization via Redis. - * All nodes in the cluster are guaranteed to have a *subset* view of the current accurate state, though individual processes may have different items in their local cache. - * This ensures that a call to get() will never return stale data. - */ -export class QuantumKVCache<T> implements Iterable<[key: string, value: T]> { - private readonly memoryCache: MemoryKVCache<T>; - - public readonly fetcher: QuantumKVOpts<T>['fetcher']; - public readonly onSet: QuantumKVOpts<T>['onSet']; - public readonly onDelete: QuantumKVOpts<T>['onDelete']; - - /** - * @param internalEventService Service bus to synchronize events. - * @param name Unique name of the cache - must be the same in all processes. - * @param opts Cache options - */ - constructor( - private readonly internalEventService: InternalEventService, - private readonly name: string, - opts: QuantumKVOpts<T>, - ) { - this.memoryCache = new MemoryKVCache(opts.lifetime); - this.fetcher = opts.fetcher; - this.onSet = opts.onSet; - this.onDelete = opts.onDelete; - - this.internalEventService.on('quantumCacheUpdated', this.onQuantumCacheUpdated, { - // Ignore our own events, otherwise we'll immediately erase any set value. - ignoreLocal: true, - }); - } - - /** - * The number of items currently in memory. - * This applies to the local subset view, not the cross-cluster cache state. - */ - public get size() { - return this.memoryCache.size; - } - - /** - * Iterates all [key, value] pairs in memory. - * This applies to the local subset view, not the cross-cluster cache state. - */ - @bindThis - public *entries(): Generator<[key: string, value: T]> { - for (const entry of this.memoryCache.entries) { - yield [entry[0], entry[1].value]; - } - } - - /** - * Iterates all keys in memory. - * This applies to the local subset view, not the cross-cluster cache state. - */ - @bindThis - public *keys() { - for (const entry of this.memoryCache.entries) { - yield entry[0]; - } - } - - /** - * Iterates all values pairs in memory. - * This applies to the local subset view, not the cross-cluster cache state. - */ - @bindThis - public *values() { - for (const entry of this.memoryCache.entries) { - yield entry[1].value; - } - } - - /** - * Creates or updates a value in the cache, and erases any stale caches across the cluster. - * Fires an onSet event after the cache has been updated in all processes. - * Skips if the value is unchanged. - */ - @bindThis - public async set(key: string, value: T): Promise<void> { - if (this.memoryCache.get(key) === value) { - return; - } - - this.memoryCache.set(key, value); - - await this.internalEventService.emit('quantumCacheUpdated', { name: this.name, op: 's', keys: [key] }); - - if (this.onSet) { - await this.onSet(key, this); - } - } - - /** - * Creates or updates multiple value in the cache, and erases any stale caches across the cluster. - * Fires an onSet for each changed item event after the cache has been updated in all processes. - * Skips if all values are unchanged. - */ - @bindThis - public async setMany(items: Iterable<[key: string, value: T]>): Promise<void> { - const changedKeys: string[] = []; - - for (const item of items) { - if (this.memoryCache.get(item[0]) !== item[1]) { - changedKeys.push(item[0]); - this.memoryCache.set(item[0], item[1]); - } - } - - if (changedKeys.length > 0) { - await this.internalEventService.emit('quantumCacheUpdated', { name: this.name, op: 's', keys: changedKeys }); - - if (this.onSet) { - for (const key of changedKeys) { - await this.onSet(key, this); - } - } - } - } - - /** - * Adds a value to the local memory cache without notifying other process. - * Neither a Redis event nor onSet callback will be fired, as the value has not actually changed. - * This should only be used when the value is known to be current, like after fetching from the database. - */ - @bindThis - public add(key: string, value: T): void { - this.memoryCache.set(key, value); - } - - /** - * Adds multiple values to the local memory cache without notifying other process. - * Neither a Redis event nor onSet callback will be fired, as the value has not actually changed. - * This should only be used when the value is known to be current, like after fetching from the database. - */ - @bindThis - public addMany(items: Iterable<[key: string, value: T]>): void { - for (const [key, value] of items) { - this.memoryCache.set(key, value); - } - } - - /** - * Gets a value from the local memory cache, or returns undefined if not found. - */ - @bindThis - public get(key: string): T | undefined { - return this.memoryCache.get(key); - } - - /** - * Gets or fetches a value from the cache. - * Fires an onSet event, but does not emit an update event to other processes. - */ - @bindThis - public async fetch(key: string): Promise<T> { - let value = this.memoryCache.get(key); - if (value === undefined) { - value = await this.fetcher(key, this); - this.memoryCache.set(key, value); - - if (this.onSet) { - await this.onSet(key, this); - } - } - return value; - } - - /** - * Returns true is a key exists in memory. - * This applies to the local subset view, not the cross-cluster cache state. - */ - @bindThis - public has(key: string): boolean { - return this.memoryCache.get(key) !== undefined; - } - - /** - * Deletes a value from the cache, and erases any stale caches across the cluster. - * Fires an onDelete event after the cache has been updated in all processes. - */ - @bindThis - public async delete(key: string): Promise<void> { - this.memoryCache.delete(key); - - await this.internalEventService.emit('quantumCacheUpdated', { name: this.name, op: 'd', keys: [key] }); - - if (this.onDelete) { - await this.onDelete(key, this); - } - } - /** - * Deletes multiple values from the cache, and erases any stale caches across the cluster. - * Fires an onDelete event for each key after the cache has been updated in all processes. - * Skips if the input is empty. - */ - @bindThis - public async deleteMany(keys: string[]): Promise<void> { - if (keys.length === 0) { - return; - } - - for (const key of keys) { - this.memoryCache.delete(key); - } - - await this.internalEventService.emit('quantumCacheUpdated', { name: this.name, op: 'd', keys }); - - if (this.onDelete) { - for (const key of keys) { - await this.onDelete(key, this); - } - } - } - - /** - * Refreshes the value of a key from the fetcher, and erases any stale caches across the cluster. - * Fires an onSet event after the cache has been updated in all processes. - */ - @bindThis - public async refresh(key: string): Promise<T> { - const value = await this.fetcher(key, this); - await this.set(key, value); - return value; - } - - /** - * Erases all entries from the local memory cache. - * Does not send any events or update other processes. - */ - @bindThis - public clear() { - this.memoryCache.clear(); - } - - /** - * Removes expired cache entries from the local view. - * Does not send any events or update other processes. - */ - @bindThis - public gc() { - this.memoryCache.gc(); - } - - /** - * Erases all data and disconnects from the cluster. - * This *must* be called when shutting down to prevent memory leaks! - */ - @bindThis - public dispose() { - this.internalEventService.off('quantumCacheUpdated', this.onQuantumCacheUpdated); - - this.memoryCache.dispose(); - } - - @bindThis - private async onQuantumCacheUpdated(data: InternalEventTypes['quantumCacheUpdated']): Promise<void> { - if (data.name === this.name) { - for (const key of data.keys) { - this.memoryCache.delete(key); - - if (data.op === 's' && this.onSet) { - await this.onSet(key, this); - } - - if (data.op === 'd' && this.onDelete) { - await this.onDelete(key, this); - } - } - } - } - - /** - * Iterates all [key, value] pairs in memory. - * This applies to the local subset view, not the cross-cluster cache state. - */ - [Symbol.iterator](): Iterator<[key: string, value: T]> { - return this.entries(); - } -} |