merge: Add separate redis for rate limit (!908)

View MR for information: https://activitypub.software/TransFem-org/Sharkey/-/merge_requests/908

Approved-by: dakkar <dakkar@thenautilus.net>
Approved-by: Marie <github@yuugi.dev>

5 files changed, 19 insertions, 4 deletions

diff --git a/packages/backend/src/GlobalModule.ts b/packages/backend/src/GlobalModule.ts
index ace7f7841c..7ca566477d 100644
--- a/packages/backend/src/GlobalModule.ts
+++ b/packages/backend/src/GlobalModule.ts
@@ -92,6 +92,14 @@ const $redisForReactions: Provider = {
 	inject: [DI.config],
 };
 
+const $redisForRateLimit: Provider = {
+	provide: DI.redisForRateLimit,
+	useFactory: (config: Config) => {
+		return new Redis.Redis(config.redisForRateLimit);
+	},
+	inject: [DI.config],
+};
+
 const $meta: Provider = {
 	provide: DI.meta,
 	useFactory: async (db: DataSource, redisForSub: Redis.Redis) => {
@@ -152,8 +160,8 @@ const $meta: Provider = {
 @Global()
 @Module({
 	imports: [RepositoryModule],
-	providers: [$config, $db, $meta, $meilisearch, $redis, $redisForPub, $redisForSub, $redisForTimelines, $redisForReactions],
-	exports: [$config, $db, $meta, $meilisearch, $redis, $redisForPub, $redisForSub, $redisForTimelines, $redisForReactions, RepositoryModule],
+	providers: [$config, $db, $meta, $meilisearch, $redis, $redisForPub, $redisForSub, $redisForTimelines, $redisForReactions, $redisForRateLimit],
+	exports: [$config, $db, $meta, $meilisearch, $redis, $redisForPub, $redisForSub, $redisForTimelines, $redisForReactions, $redisForRateLimit, RepositoryModule],
 })
 export class GlobalModule implements OnApplicationShutdown {
 	constructor(
@@ -163,6 +171,7 @@ export class GlobalModule implements OnApplicationShutdown {
 		@Inject(DI.redisForSub) private redisForSub: Redis.Redis,
 		@Inject(DI.redisForTimelines) private redisForTimelines: Redis.Redis,
 		@Inject(DI.redisForReactions) private redisForReactions: Redis.Redis,
+		@Inject(DI.redisForRateLimit) private redisForRateLimit: Redis.Redis,
 	) { }
 
 	public async dispose(): Promise<void> {
@@ -176,6 +185,7 @@ export class GlobalModule implements OnApplicationShutdown {
 			this.redisForSub.disconnect(),
 			this.redisForTimelines.disconnect(),
 			this.redisForReactions.disconnect(),
+			this.redisForRateLimit.disconnect(),
 		]);
 	}
 
diff --git a/packages/backend/src/config.ts b/packages/backend/src/config.ts
index 24f3c472a4..3c76c76469 100644
--- a/packages/backend/src/config.ts
+++ b/packages/backend/src/config.ts
@@ -53,6 +53,7 @@ type Source = {
 	redisForJobQueue?: RedisOptionsSource;
 	redisForTimelines?: RedisOptionsSource;
 	redisForReactions?: RedisOptionsSource;
+	redisForRateLimit?: RedisOptionsSource;
 	fulltextSearch?: {
 		provider?: FulltextSearchProvider;
 	};
@@ -231,6 +232,7 @@ export type Config = {
 	redisForJobQueue: RedisOptions & RedisOptionsSource;
 	redisForTimelines: RedisOptions & RedisOptionsSource;
 	redisForReactions: RedisOptions & RedisOptionsSource;
+	redisForRateLimit: RedisOptions & RedisOptionsSource;
 	sentryForBackend: { options: Partial<Sentry.NodeOptions>; enableNodeProfiling: boolean; } | undefined;
 	sentryForFrontend: { options: Partial<Sentry.NodeOptions> } | undefined;
 	perChannelMaxNoteCacheCount: number;
@@ -345,6 +347,7 @@ export function loadConfig(): Config {
 		redisForJobQueue: config.redisForJobQueue ? convertRedisOptions(config.redisForJobQueue, host) : redis,
 		redisForTimelines: config.redisForTimelines ? convertRedisOptions(config.redisForTimelines, host) : redis,
 		redisForReactions: config.redisForReactions ? convertRedisOptions(config.redisForReactions, host) : redis,
+		redisForRateLimit: config.redisForRateLimit ? convertRedisOptions(config.redisForRateLimit, host) : redis,
 		sentryForBackend: config.sentryForBackend,
 		sentryForFrontend: config.sentryForFrontend,
 		id: config.id,
@@ -535,7 +538,7 @@ function applyEnvOverrides(config: Source) {
 	_apply_top(['db', ['host', 'port', 'db', 'user', 'pass', 'disableCache']]);
 	_apply_top(['dbSlaves', Array.from((config.dbSlaves ?? []).keys()), ['host', 'port', 'db', 'user', 'pass']]);
 	_apply_top([
-		['redis', 'redisForPubsub', 'redisForJobQueue', 'redisForTimelines', 'redisForReactions'],
+		['redis', 'redisForPubsub', 'redisForJobQueue', 'redisForTimelines', 'redisForReactions', 'redisForRateLimit'],
 		['host', 'port', 'username', 'pass', 'db', 'prefix'],
 	]);
 	_apply_top(['fulltextSearch', 'provider']);
diff --git a/packages/backend/src/di-symbols.ts b/packages/backend/src/di-symbols.ts
index 9f4ef5e2e9..461fcf11c3 100644
--- a/packages/backend/src/di-symbols.ts
+++ b/packages/backend/src/di-symbols.ts
@@ -13,6 +13,7 @@ export const DI = {
 	redisForSub: Symbol('redisForSub'),
 	redisForTimelines: Symbol('redisForTimelines'),
 	redisForReactions: Symbol('redisForReactions'),
+	redisForRateLimit: Symbol('redisForRateLimit'),
 
 	//#region Repositories
 	usersRepository: Symbol('usersRepository'),
diff --git a/packages/backend/src/server/SkRateLimiterService.md b/packages/backend/src/server/SkRateLimiterService.md
index fb007538fa..c8a2b4e85c 100644
--- a/packages/backend/src/server/SkRateLimiterService.md
+++ b/packages/backend/src/server/SkRateLimiterService.md
@@ -39,6 +39,7 @@ The first call is read-only, while the others perform at least one write operati
 Two integer keys are stored per client/subject, and both expire together after the maximum duration of the limit.
 While performance has not been formally tested, it's expected that SkRateLimiterService has an impact roughly on par with the legacy RateLimiterService.
 Redis memory usage should be notably lower due to the reduced number of keys and avoidance of set / array constructions.
+If redis load does become a concern, then a dedicated node can be assigned via the `redisForRateLimit` config setting.
 
 ## Concurrency and Multi-Node Correctness
 
diff --git a/packages/backend/src/server/SkRateLimiterService.ts b/packages/backend/src/server/SkRateLimiterService.ts
index 038f12cb25..30bf092e4f 100644
--- a/packages/backend/src/server/SkRateLimiterService.ts
+++ b/packages/backend/src/server/SkRateLimiterService.ts
@@ -27,7 +27,7 @@ export class SkRateLimiterService {
 		@Inject('TimeService')
 		private readonly timeService: TimeService,
 
-		@Inject(DI.redis)
+		@Inject(DI.redisForRateLimit)
 		private readonly redisClient: Redis.Redis,
 
 		@Inject('RoleService')