Variables

Variables represent a datacenter's need to receive input from operators to function properly. Oftentimes this is simply the credentials needed to access the cloud providers the datacenter uses, but can also include configuration settings like default log levels, regions to deploy into, etc.

Declaring variables

variable "do_token" {
  description = "The digital ocean API token"
  type = "string"
}

variable "region" {
  description = "The region to create resources in"
  type = "string"
  default = "nyc1"
}

variable "dns_zone" {
  description = "DNS zone to use for ingress rules"
  type = "string"
}

Using variables

Declared variables can then be used to enrich any modules throughout the datacenter using HCL references like ${variable.do_token}.

module "vpc" {
  build = "./vpc"
  inputs = {
    region = variable.region
  }
}

environment {
  module "postgresCluster" {
    build = "./databaseCluster"
    inputs = {
      region = variable.region
    }
  }

  database {
    when = node.inputs.databaseType == "postgres"

    module "database" {
      build = "./database"
      inputs = {
        "digitalocean:token" = variable.do_token
      }
    }

    outputs = {}
  }
}

Setting values

Setting variable values can be done every time changes are applied to your datacenters using the --var command line flag:

$ arcctl apply datacenter --var do_token=abc123 --var region=nyc1

Alternatively, you can set these values using environment variables which can be helpful for CI systems or re-used values. You can set any value with an environment variable prefixed with ARC_:

ARC_do_token=abc123
ARC_region=nyc1

Variable storage

The variable values need to be persisted so that they can be used when developers create environments or trigger deployments. These requests need to use these values for their configuration even though the datacenter configuration hasn't been changed.

Architect stores the variable values inside the datacenter's state file. Click here to learn more about Architect's state management.