# Cache

The **Cache** action allows developers to interact with the store's Mechanic [**cache**](https://learn.mechanic.dev/platform/cache), using commands inspired by Redis. Cache entries have a **key**, a **value** containing up to 256 kilobytes, and a **ttl** value ("Time To Live") in seconds, defaulting to the maximum of 60 days (i.e. 5184000 seconds).

{% hint style="info" %}
Cache actions (like all actions) are performed after their task run is completed. The results of Cache actions therefore aren't reflected during the task run that generates them.
{% endhint %}

## Options

This action supports two styles of options: a more verbose nested structure, and a simpler set of positional arguments.

All commands must define a cache key, matching the regular expression `/^[a-z0-9_:\-\.\/]+$/i`.

### Verbose options

In this option style, the cache command is given as the root key of the options object. The root value is itself an option, containing the arguments needed for the selected cache command.

{% tabs %}
{% tab title="Liquid" %}

```liquid
{% action "cache" %}
  {
    "incr": {
      "key": "foo",
      "ttl": 600
    }
  }
{% endaction %}
```

{% endtab %}
{% endtabs %}

### Positional options

In this option style, the cache command and its arguments are given in a list. Use the cache command reference below to find the argument order required for each command.

{% tabs %}
{% tab title="Liquid" %}

```liquid
{% action "cache", "incr", "foo" %}
```

{% endtab %}
{% endtabs %}

## Expiration

Each cache entry is given a default TTL value of 60 days, or 5184000 seconds. (A cache entry's TTL may not exceed 60 days.)

A cache command will always reset the entry's TTL value upon execution, regardless of the TTL's original value.

## Commands

The required arguments for each command are given below, in the order in which they are supported for [positional options](#positional-options).

When a command is given using [verbose options](#verbose-options), the `ttl` value (in seconds) is always supported.

### set

Stores a value. Requires `key` and `value`. The stored value may be any JSON object.

### setex

Using a defined TTL (an expiration interval) given in seconds, stores a value. Requires `key`, `ttl`, and `value`. The stored value may be any JSON object.

{% hint style="info" %}
The "setex" command has the same net functionality as "set", but it does have one difference: because "setex" requires an explicit `ttl` value, it's possible to use "setex" to express an expiring value using a single line of Liquid. The same result could be achieved with "set", but it would require using verbose options.

```liquid
{% action "cache", "setex", "foo", 5, "bar" %}
```

{% endhint %}

### del

Deletes a stored key. Requires `key`.

### incr

Increments a numeric key by 1. Requires `key`. If the key is not already set, the value before incrementing will be assumed to be 0.

### incrby

Increments a numeric key by the value of your choice. Requires `key`, and an integer `increment`. If the key is not already set, the value before incrementing will be assumed to be 0.

### decr

Decrements a numeric key by 1. Requires `key`. If the key is not already set, the value before incrementing will be assumed to be 0.

### decrby

Decrements a numeric key by the value of your choice. Requires `key`, and an integer `decrement`. If the key is not already set, the value before incrementing will be assumed to be 0.

## Examples

### Set a value, auto-expiring in 60 days

{% tabs %}
{% tab title="Verbose options" %}

```liquid
{% action "cache" %}
  {
    "set": {
      "key": "foo",
      "value": 5
    }
  }
{% endaction %}
```

{% endtab %}

{% tab title="Positional options" %}

```liquid
{% action "cache", "set", "foo", 5 %}
```

{% endtab %}
{% endtabs %}

### Set a value, explicitly expiring in 1 minute

{% tabs %}
{% tab title="Verbose options" %}

```liquid
{% action "cache" %}
  {
    "setex": {
      "key": "foo",
      "ttl": 60,
      "value": 5
    }
  }
{% endaction %}
```

{% endtab %}

{% tab title="Positional options" %}

```liquid
{% action "cache", "setex", "foo", 60, 5 %}
```

{% endtab %}
{% endtabs %}

### Clear a value

{% tabs %}
{% tab title="Verbose options" %}

```liquid
{% action "cache" %}
  {
    "del": {
      "key": "foo"
    }
  }
{% endaction %}
```

{% endtab %}

{% tab title="Positional options" %}

```liquid
{% action "cache", "del", "foo" %}
```

{% endtab %}
{% endtabs %}