---
title: Custom Store
description: Implement a custom store backend for Warden.
---

You can implement a custom store by satisfying the `store.Store` interface.

## Store Interface

The composite store interface embeds all subsystem stores:

```go
import "github.com/xraph/warden/store"

type Store interface {
    role.Store
    permission.Store
    assignment.Store
    relation.Store
    policy.Store
    resourcetype.Store
    checklog.Store

    Migrate(ctx context.Context) error
    Ping(ctx context.Context) error
    Close() error
}
```

## Subsystem Interfaces

Each subsystem defines its own store interface. Here's an overview:

### role.Store

```go
type Store interface {
    CreateRole(ctx context.Context, r *Role) error
    GetRole(ctx context.Context, id id.RoleID) (*Role, error)
    UpdateRole(ctx context.Context, r *Role) error
    DeleteRole(ctx context.Context, id id.RoleID) error
    ListRoles(ctx context.Context, filter *ListFilter) ([]*Role, error)
    CountRoles(ctx context.Context, filter *ListFilter) (int, error)
    AttachPermission(ctx context.Context, roleID id.RoleID, permID id.PermissionID) error
    DetachPermission(ctx context.Context, roleID id.RoleID, permID id.PermissionID) error
    ListPermissionsForRole(ctx context.Context, roleID id.RoleID) ([]id.PermissionID, error)
    GetRoleBySlug(ctx context.Context, slug string) (*Role, error)
    ListChildRoles(ctx context.Context, parentID id.RoleID) ([]*Role, error)
    ListRolesForSubject(ctx context.Context, tenantID, subjectKind, subjectID string) ([]id.RoleID, error)
    DeleteByTenant(ctx context.Context, tenantID string) error
}
```

### Other subsystem stores follow the same pattern:
- `permission.Store` — CRUD + role attachment queries
- `assignment.Store` — CRUD + subject/role lookups
- `relation.Store` — CRUD + graph traversal queries
- `policy.Store` — CRUD + active policy lookups
- `resourcetype.Store` — CRUD + name lookups
- `checklog.Store` — Append + query

## Implementation Tips

1. **Start with the memory store** as a reference: `store/memory/store.go`
2. **Use compile-time checks** to ensure interface compliance:
   ```go
   var _ store.Store = (*MyStore)(nil)
   ```
3. **Thread safety** — Use appropriate locking for concurrent access
4. **Tenant isolation** — All queries should filter by tenant ID from context
5. **Error mapping** — Return `warden.ErrNotFound` for missing entities, `warden.ErrAlreadyExists` for duplicates

## Example Skeleton

```go
package mystore

import (
    "context"
    "github.com/xraph/warden/store"
)

type MyStore struct {
    // your database client
}

var _ store.Store = (*MyStore)(nil)

func (s *MyStore) Migrate(ctx context.Context) error {
    // Run migrations
    return nil
}

func (s *MyStore) Ping(ctx context.Context) error {
    // Health check
    return nil
}

func (s *MyStore) Close() error {
    // Close connections
    return nil
}

// Implement all subsystem store methods...
```