Advanced configuration topics

Using a template engine

Steep contains a template engine that allows you to dynamically generate content for YAML-based configuration files (steep.yaml, setups.yaml, services/services.yaml, etc.) at startup.

You have to explicitly enable this feature by adding front matter to your YAML file and setting the attribute template to true:

---
template: true
---

Steep uses Pebble Templates to compile the configuration files. Please refer to their website for a full documentation on the tags, functions, and filters you can use.

Within your template, you may access the following variables:

Variable	Description
`env`	A dictionary of environment variables. Use subscript notation (`[]`) to access its contents. Example: `{{ env["PATH"] }}`
`config`	A dictionary of configuration properties. This variable is not available in `steep.yaml` (or any override configuration file). Use subscript notation (`[]`) to access its contents. Example: `{{ config["steep.cluster.hazelcast.publicAddress"] }}`

Here is a full example of a setups.yaml file that uses the templating feature to create two setups with the same parameters, an image name from an environment variable, but different availability zones:

---
template: true
---
 
{% for az in ["us-east-1", "eu-central-1"] %}
- id: my_setup_{{ az }}
  flavor: m4.2xlarge
  availabilityZone: {{ az }}
  imageName: {{ env["MY_SETUP_IMAGE_NAME"] }
  blockDeviceSizeGb: 50
  minVMs: 0
  maxVMs: 10
{% endfor %}

Using YAML anchors

Overview