TTL policy

A TTL (time-to-live) policy destroys a stack and everything in it once a set duration has passed. It’s the mechanism for ephemeral infrastructure: dev workspaces, test environments, demos, anything that should clean itself up without someone remembering to run destroy.

How it works

The countdown starts when the stack is first created with the policy attached, and it counts down in the background: no apply is needed to trigger the eventual destroy. Re-applying the stack does not restart the clock; it always counts from the original creation time. When the TTL expires, formae destroys the stack and all its resources.

Configuration

Property	Type	Description
`ttl`	Duration	How long the stack should live, for example `1.h`, `24.h`, `7.d`
`onDependents`	`"abort"` \| `"cascade"`	What to do if resources outside the stack depend on it. Defaults to `"abort"`

onDependents

When the TTL expires, formae checks whether any resource outside the stack depends on a resource inside it:

abort (default): cancel the destruction. The stack stays intact until the dependency is removed.
cascade: delete the dependent resources too, following the dependency chain into other stacks.

cascade can delete resources in stacks you didn’t intend to touch, anywhere the dependency chain leads. Use abort unless you’re certain nothing outside the stack should survive it.

Examples

Inline TTL policy:

amends "@formae/forma.pkl"

import "@formae/formae.pkl"
import "@aws/aws.pkl"
import "@aws/logs/loggroup.pkl"

local devTarget = new formae.Target {
  label = "dev-target"
  config = new aws.Config {
    region = "us-east-1"
  }
}

forma {
  devTarget

  new formae.Stack {
    label = "feature-xyz"
    description = "Temporary dev environment for feature XYZ"
    policies = new Listing {
      new formae.TTLPolicy {
        ttl = 8.h              // Destroy after 8 hours
        onDependents = "abort" // Don't destroy if other resources depend on it
      }
    }
  }

  new loggroup.LogGroup {
    label = "feature-logs"
    stack = "feature-xyz"
    target = devTarget.res
    logGroupName = "/dev/feature-xyz/logs"
    retentionInDays = 1
  }
}

Reusable TTL policy, shared by every developer’s sandbox stack:

amends "@formae/forma.pkl"

import "@formae/formae.pkl"
import "@aws/aws.pkl"
import "@aws/logs/loggroup.pkl"

local ephemeralPolicy = new formae.TTLPolicy {
  label = "ephemeral-4h"
  ttl = 4.h
  onDependents = "cascade"
}

local devTarget = new formae.Target {
  label = "dev-target"
  config = new aws.Config {
    region = "us-east-1"
  }
}

forma {
  ephemeralPolicy
  devTarget

  new formae.Stack {
    label = "alice-dev"
    description = "Alice's development environment"
    policies = new Listing { ephemeralPolicy.res }
  }

  new loggroup.LogGroup {
    label = "alice-logs"
    stack = "alice-dev"
    target = devTarget.res
    logGroupName = "/dev/alice/logs"
  }

  new formae.Stack {
    label = "bob-dev"
    description = "Bob's development environment"
    policies = new Listing { ephemeralPolicy.res }
  }

  new loggroup.LogGroup {
    label = "bob-logs"
    stack = "bob-dev"
    target = devTarget.res
    logGroupName = "/dev/bob/logs"
  }
}

Use cases

Development environments that clean themselves up at the end of the workday.
CI/CD test infrastructure that disappears once the test run finishes with it.
Demo environments that auto-destroy after the demo window.
Cost control: forgotten resources stop accumulating cost on their own.

Monitoring

formae inventory stacks

Shows every stack’s attached policies, including TTL and its expiry.

Get started

Guides

Concepts

Reference

How it works

Configuration

onDependents

Examples

Use cases

Monitoring

See also

​How it works

​Configuration

​onDependents

​Examples

​Use cases

​Monitoring

​See also

How it works

Configuration

onDependents

Examples

Use cases

Monitoring

See also