Polizy Storage

Storage adapters handle persistence of authorization tuples.

When to Apply

• User asks "set up database storage"
• User asks "use Prisma with polizy"
• User asks "create custom storage adapter"
• User asks about "production storage"
• User has performance concerns with authorization

Adapter Comparison

Feature	InMemoryStorageAdapter	PrismaAdapter
Persistence	No (RAM only)	Yes (database)
Multi-instance	No	Yes
Setup	Zero config	Prisma model required
Performance	Fastest	Good with indexes
Use case	Testing, dev	Production

Quick Setup

InMemory (Development/Testing)

import { AuthSystem, InMemoryStorageAdapter } from "polizy";

const storage = new InMemoryStorageAdapter();
const authz = new AuthSystem({ storage, schema });

Prisma (Production)

import { AuthSystem } from "polizy";
import { PrismaAdapter } from "polizy/prisma-storage";
import { PrismaClient } from "@prisma/client";

const prisma = new PrismaClient();
const storage = PrismaAdapter(prisma);
const authz = new AuthSystem({ storage, schema });

Requires Prisma model - see PRISMA-ADAPTER.md

InMemoryStorageAdapter

When to Use

• Unit tests
• Development environment
• Single-process applications
• Prototyping

Behavior

• Data stored in JavaScript Map
• Lost on process restart
• No network latency
• Fastest possible reads

Testing Example

import { describe, it, beforeEach } from "node:test";
import { AuthSystem, InMemoryStorageAdapter, defineSchema } from "polizy";

describe("authorization", () => {
  let authz: AuthSystem<typeof schema>;

  beforeEach(() => {
    // Fresh storage for each test
    const storage = new InMemoryStorageAdapter();
    authz = new AuthSystem({ storage, schema });
  });

  it("grants access correctly", async () => {
    await authz.allow({
      who: { type: "user", id: "alice" },
      toBe: "owner",
      onWhat: { type: "doc", id: "doc1" }
    });

    const result = await authz.check({
      who: { type: "user", id: "alice" },
      canThey: "edit",
      onWhat: { type: "doc", id: "doc1" }
    });

    assert.strictEqual(result, true);
  });
});

PrismaAdapter

When to Use

• Production environments
• Multi-instance deployments
• Need audit trail
• Data must survive restarts

Setup Steps

1. Install dependencies

   npm install @prisma/client
   npm install -D prisma
   

2. Add Prisma model (see PRISMA-ADAPTER.md)

3. Run migrations

   npx prisma migrate dev --name add_polizy
   

4. Use adapter

   import { PrismaAdapter } from "polizy/prisma-storage";
   const storage = PrismaAdapter(prisma);
   

Storage Interface

All adapters implement:

interface StorageAdapter<S, O> {
  write(tuples: InputTuple[]): Promise<StoredTuple[]>;
  delete(filter: DeleteFilter): Promise<number>;
  findTuples(filter: TupleFilter): Promise<StoredTuple[]>;
  findSubjects(object, relation, options?): Promise<Subject[]>;
  findObjects(subject, relation, options?): Promise<AnyObject[]>;
}

Common Patterns

Shared Storage Instance

// storage.ts
import { InMemoryStorageAdapter } from "polizy";
// or: import { PrismaAdapter } from "polizy/prisma-storage";

export const storage = new InMemoryStorageAdapter();
// or: export const storage = PrismaAdapter(prisma);

// auth.ts
import { AuthSystem } from "polizy";
import { storage } from "./storage";
import { schema } from "./schema";

export const authz = new AuthSystem({ storage, schema });

Environment-Based Selection

import { AuthSystem, InMemoryStorageAdapter } from "polizy";
import { PrismaAdapter } from "polizy/prisma-storage";
import { PrismaClient } from "@prisma/client";

function createStorage() {
  if (process.env.NODE_ENV === "test") {
    return new InMemoryStorageAdapter();
  }

  const prisma = new PrismaClient();
  return PrismaAdapter(prisma);
}

const storage = createStorage();
export const authz = new AuthSystem({ storage, schema });

Performance Considerations

Concern	Solution
Slow reads	Add database indexes
Too many queries	Reduce group nesting depth
Large tuple counts	Periodic cleanup of expired tuples
Batch operations	Use writeTuple with parallel Promise.all

Common Issues

Issue	Solution
Data lost on restart	Switch from InMemory to Prisma
"Table doesn't exist"	Run npx prisma migrate deploy
Slow checks	Reduce group/hierarchy depth
Memory growing	Clean up expired conditional tuples

References

• PRISMA-ADAPTER.md - Full Prisma setup
• CUSTOM-ADAPTERS.md - Building custom adapters
• PERFORMANCE.md - Optimization strategies

Related Skills

• polizy-setup - Initial setup
• polizy-troubleshooting - Debugging