# OpenSpec Change: enterprise-server-cache-memory

- **Change ID**: enterprise-server-cache-memory
- **Package**: `@suaveplan/cache-memory`
- **Category**: server/data
- **Target path**: `server/data/cache-memory`
- **Status**: PROPOSED
- **Date**: 2026-04-24
- **Reference spec**: `/mnt/s/web/suaveplan/enterprise/cache-memory.md`

---

## Summary

Deliver `@suaveplan/cache-memory` on the genesis branch from scratch at enterprise quality. The package provides a zero-dependency, in-process LRU + TTL cache adapter implementing the same interface contract as `@suaveplan/cache-redis`. It is the primary testing stand-in and the default cache for single-server deployments. Genesis ships with a doubly-linked-list LRU eviction algorithm, injectable `Clock` for deterministic time testing, Zod-validated options, OTel counters/histograms, structured logging, and 100% test coverage via property-based tests.

---

## Current-state audit (genesis)

Does not exist on genesis — fresh build.

---

## Available workspace deps on genesis

| Package | Role |
|---|---|
| `@suaveplan/error` (`workspace:^`) | Typed error codes for `CACHE_MEMORY.*` |
| `@suaveplan/types` (`workspace:^`) | `StorageLike`, `LoggerLike`, `Clock` |
| `@suaveplan/logger` (`workspace:^`) | Structured logs |
| `zod` (`catalog:forms`) | Options validation |
| `@opentelemetry/api` (`catalog:observability`) | Counters + histograms |
| `tslib` (`catalog:build`) | Runtime helpers |

---

## Public API surface

### Adapter

```ts
class MemoryCacheAdapter {
  constructor(options?: MemoryCacheOptions)
  get(key: string): Promise<Uint8Array | undefined>
  set(key: string, value: Uint8Array, ttlMs?: number): Promise<void>
  delete(key: string): Promise<boolean>
  has(key: string): Promise<boolean>
  list(prefix?: string): Promise<string[]>
  clear(): Promise<void>
  ttl(key: string): Promise<number | undefined>
  size(): number
  stats(): CacheStats
}

function createMemoryCacheAdapter(options?: MemoryCacheOptions): MemoryCacheAdapter
```

### Options + types

```ts
interface MemoryCacheOptions {
  maxSize?: number         // max number of entries, default: 1000
  defaultTtlMs?: number    // default TTL when none supplied; undefined = no expiry
  clock?: Clock            // injectable for testing
  logger?: LoggerLike
}

interface CacheStats {
  hits: number
  misses: number
  evictions: number
  size: number
  hitRate: number
}

const MemoryCacheOptionsSchema: z.ZodSchema<MemoryCacheOptions>
```

### Error codes

```ts
type MemoryCacheErrorCode =
  | 'CACHE_MEMORY_INVALID_KEY'
  | 'CACHE_MEMORY_CAPACITY_EXCEEDED'

function registerMemoryCacheErrorCodes(): void
```

---

## File layout

```text
server/data/cache-memory/
  package.json
  tsconfig.json
  vitest.config.ts
  src/
    index.ts
    error-codes.ts
    constants/
      index.ts
    types/
      cache-memory.types.ts
      cache-memory.types.md
    adapter/
      memory-cache-adapter/
        memory-cache-adapter.ts
        memory-cache-adapter.md
        memory-cache-adapter.types.ts
        memory-cache-adapter.test.ts
        index.ts
    lru/
      lru-cache/
        lru-cache.ts
        lru-cache.md
        lru-cache.test.ts
        index.ts
  tests/
    property.test.ts
```

---

## Impact

Downstream consumers: testing utilities, unit-test doubles for packages that depend on `cache-redis`. Universal helper — no Node.js IO, pure in-process.

**Prerequisites on Verdaccio**: `@suaveplan/error`, `@suaveplan/types`, `@suaveplan/logger`.