002 - Auto Deploys, Component Dependencies and Graphs

Jan 16th, 2024

​

Auto Deployed Components

Last week, we shipped auto-deploys. Auto deploys mean that whenever a new install is created, all existing components are automatically deployed to the install in the correct order.

Now, when you create an app using the nuon cli, an an sdk, or using an installer - each component in the app will automatically be deployed to, without you having to run a release. This requires an intelligent representation of apps under the hood, and we have built out support for component dependencies and infra to model each app as a directed acyclic graph under the hood.

​

Component dependencies

You can declare a dependency between any component using our terraform provider, simply add a dependencies block:

resource "nuon_helm_chart_component" "helm" {
  name   = "helm"
  app_id = nuon_app.main.id

  dependencies = [
    nuon_terraform_module_component.database.id
    nuon_docker_build_component.image.id
  ]
  chart_name = "helm"
  connected_repo = {
    directory = "helm"
    repo      = "nuonco/mono"
    branch    = "main"
  }
}

When you apply your app config, we will automatically look out for cycles and error if your dependencies are invalid:

​

Deprovisioning order

Now, when you deprovision an install, Nuon will automatically walk through each deployed component on the install and deprovision it according to the dependencies. This prevents situations where installs could fail to deprovision due to leaked component resources and others.

​

Apps as graphs

Under the hood, we use component dependencies to create a graph of each application, and model the relationships between each component properly. Let’s say you are deploying a Helm packaged app, that requires a database managed by Terraform.

Your Nuon config will have two components, your Terraform component and a Helm component.

resource "nuon_terraform_module_component" "database" {
  name   = "database"
  app_id = nuon_app.main.id
  terraform_version = "1.6.3"

  connected_repo = {
    directory = "infra"
    repo      = "nuonco/mono"
    branch    = "main"
  }

  env_var {
    name  = "install_id"
    value = "{{.nuon.install.id}}"
  }
}

However, in order for the Helm component to be properly deployed, it must know about the some of the outputs from the Terraform component. In this example, the database component must be provisioned before the helm chart when creating the install. When destroying the install, the helm chart must be deprovisioned first.

Now, with dependencies, these types of relationships can automatically be created.