Feature flags
Storage
In @workertown/feature-flags, storage is used to persist data about your feature flags.
For more information on how storage works in Workertown services more generally, see storage
StorageAdapter
The StorageAdapter interface is defined as follows:
interface FlagCondition {
field: string;
operator: "eq" | "neq" | "gt" | "gte" | "lt" | "lte" | "in" | "nin";
value: string | number | boolean | string[] | number[] | boolean[];
}
interface Flag {
name: string;
description?: string;
enabled: boolean;
conditions?: FlagCondition[];
createdAt: Date;
updatedAt: Date;
}
interface UpsertFlagBody {
name: string;
description?: string;
enabled: boolean;
conditions?: FlagCondition[];
}
declare class StorageAdapter {
getFlags(disabled: boolean = false): Promise<Flag[]>;
getFlag(name: string): Promise<Flag | null>;
upsertFlag(flag: UpsertFlagBody): Promise<Flag>;
deleteFlag(name: string): Promise<void>:
}
Built-in StorageAdapters
@workertown/feature-flags provides several built-in StorageAdapters that can be used via the runtime configuration option.
D1StorageAdapter
The D1StorageAdapter is the default StorageAdapter and is used when no other StorageAdapter is specified. It uses Cloudflare's D1 to store the data.
import { featureFlags } from "@workertown/feature-flags";
import { D1StorageAdapter } from "@workertown/feature-flags/storage/d1";
export default featureFlags({
runtime: (options, env) => ({
cache: false,
storage: new D1StorageAdapter({ d1: env.D1 }), // `d1` is the D1 database bound to the Cloudflare Worker to use for storage
}),
});
PlanetscaleStorageAdapter
The PlanetscaleStorageAdapter uses Planetscale (a distributed MySQL solution) to store the data.
import { featureFlags } from "@workertown/feature-flags";
import { PlanetscaleStorageAdapter } from "@workertown/feature-flags/storage/planetscale";
export default featureFlags({
runtime: (options, env) => ({
cache: false,
storage: new PlanetscaleStorageAdapter({
url: env.PLANETSCALE_URL,
username: env.PLANETSCALE_USERNAME,
password: env.PLANETSCALE_PASSWORD,
}),
}),
});
SqliteStorageAdapter
The SqliteStorageAdapter uses Sqlite to store the data. It is intended to be used in NodeJS environments as it requires access to file storage.
import { featureFlags } from "@workertown/feature-flags";
import { SqliteStorageAdapter } from "@workertown/feature-flags/storage/sqlite";
export default featureFlags({
runtime: (options, env) => ({
cache: false,
storage: new SqliteStorageAdapter({ db: env.DB }), // `db` is the file path to the `.sqlite` file to use
}),
});
TursoStorageAdapter
The TursoStorageAdapter uses Turso (a distributed SQLite solution) to store the data.
import { featureFlags } from "@workertown/feature-flags";
import { TursoStorageAdapter } from "@workertown/feature-flags/storage/turso";
export default featureFlags({
runtime: (options, env) => ({
cache: false,
storage: new TursoStorageAdapter({
url: env.TURSO_URL,
authToken: env.TURSO_AUTH_TOKEN,
}),
}),
});
MemoryStorageAdapter
The MemoryStorageAdapter is a simple StorageAdapter that stores the data in memory. It is not recommended for production use, but can be useful for development and testing.
import { featureFlags } from "@workertown/feature-flags";
import { MemoryStorageAdapter } from "@workertown/feature-flags/storage/memory";
export default featureFlags({
runtime: (options, env) => ({
cache: false,
storage: new MemoryStorageAdapter(),
}),
});
Custom StorageAdapters
You can also provide your own custom StorageAdapter by extending the StorageAdapter class.
import { featureFlags } from "@workertown/feature-flags";
import { StorageAdapter } from "@workertown/feature-flags/storage";
class CustomStorageAdapter extends StorageAdapter {
async getFlags(disabled: boolean = false) { /* ... */ },
async getFlag(name: string) { /* ... */ },
async upsertFlag(flag: UpsertFlagBody) { /* ... */ },
async deleteFlag(name: string) { /* ... */ },
}
export default featureFlags({
runtime: (options, env) => ({
cache: false,
storage: new CustomStorageAdapter(),
}),
});