Environments

What is an Environment?

Alto is designed to be used in a variety of environments. It is not uncommon to have a development environment, a staging environment, and a production environment. Alto allows you to define these environments in your configuration file.

Environment Configuration

In order to define an environment, you must add a section to your alto.toml file. The section name must be the name of the environment. Here is an example of a configuration file with 3 environments:

TOML

alto.toml

[default]
# base environment
project_name = "my-project"

# environnment 1
[dev]

# environnment 2
[github-actions]

# environnment 3
[prod]

YAML

alto.yaml

# base environment
default:
  project_name: my-project

# environnment 1
dev: {}

# environnment 2
github-actions: {}

# environnment 3
prod: {}

JSON

alto.json

{
  "default": {
    "project_name": "my-project"
  },
  "dev": {},
  "github-actions": {},
  "prod": {}
}

The 3 environments defined in this file are dev, github-actions, and prod. Alto will use the default environment as a base for all environments. This means that any configuration defined in the default environment will be the base on top of which another environment can optionally be layered.

Note

The configuration structure is the same for all environments. You can often copy and paste configuration from one environment to another, slim it down, and only change the values that need to be changed.

The ALTO_ENV Environment Variable

Alto uses the ALTO_ENV environment variable to determine which environment to use. Consider it the master control switch. If the ALTO_ENV environment variable is not set, Alto will use the default environment alone. The ALTO_ENV environment variable can be set in a number of ways. Here are the most common ways in order of precedence:

1. Via prefixing an alto command
   1. ALTO_ENV={env} alto ...
2. In your shell environment
   1. export ALTO_ENV={env}
3. In the .env file in the root of your project
   1. ALTO_ENV={env}

As you can see this follows 12-factor app principles. Alto itself leverages Dynaconf to manage configuration so we will regularly refer to the Dynaconf documentation for more information.