# `NoNoncense.MachineId.Strategy.RedisLease`
[🔗](https://github.com/juulSme/NoNoncense/blob/v2.0.0/lib/no_noncense/machine_id/strategy/redis_lease.ex#L2)

Strategy to acquire a machine ID lease from Redis, coordinating uniqueness across nodes
through a single Redis hash.

Each machine ID (`0..511`) is a field in the hash; a node acquires the lowest free ID and
holds it by keeping that field's value (a random token) alive with a TTL, renewing it
periodically.
Requires Redis 8+ or Valkey 9+ for `HSETEX`'s conditional (`FNX`/`FXX`) and per-field TTL support.

Configure the strategy when starting `NoNoncense.MachineId`, after your Redix instance or pool:

    children = [
      ...
      MyApp.Redix,
      {NoNoncense.MachineId,
       strategy: NoNoncense.MachineId.Strategy.RedisLease,
       strategy_opts: [with_connection: MyApp.Redix],
       instances: [[base_key: System.fetch_env!("BASE_KEY")]]}
    ]

## Options

  * `:with_connection` (required) supports two forms:
    1. Pass the simple connection name or pid directly:
      ```
      with_connection: MyApp.Redix
      ```
    2. To support connection pools, pass a function that calls its argument function with a connection:
      ```
      with_connection: fn fun -> :poolboy.transaction(MyApp.RedixPool, fun) end
      ```

  * `:key` - the Redis hash key to store leases under (default `"no_noncense_leases"`)

# `opt`

```elixir
@type opt() :: {:with_connection, with_connection()} | {:key, binary()}
```

# `with_connection`

```elixir
@type with_connection() ::
  ((Redix.connection() -> any()) -> any()) | Redix.connection()
```

---

*Consult [api-reference.md](api-reference.md) for complete listing*