Configuration

Lula allows the use and specification of a config file in the following ways:

• Checking current working directory for a lula-config.yaml file
• Specification with environment variable LULA_CONFIG=<path>

Environment Variables can be used to specify configuration values through use of LULA_<VAR> -> Example: LULA_TARGET=il5

Identification

If identified, Lula will log which configuration file is used to stdout:

Using config file /home/dev/work/lula/lula-config.yaml

Precedence

The precedence for configuring settings, such as target, follows this hierarchy:

Command Line Flag > Environment Variable > Configuration File

1. Command Line Flag:
   When a setting like target is specified using a command line flag, this value takes the highest precedence, overriding any environment variable or configuration file settings.

2. Environment Variable:
   If the setting is not provided via a command line flag, an environment variable (e.g., export LULA_TARGET=il5) will take precedence over the configuration file.

3. Configuration File:
   In the absence of both a command line flag and environment variable, the value specified in the configuration file will be used. This will override system defaults.

Support

Modification of command variables can be set in the configuration file:

lula-config.yaml

log_level: debug
target: il4
summary: true

Templating Configuration Fields

Templating values are set in the configuration file via the use of constants and variables fields.

Constants

A sample constants section of a lula-config.yaml file is as follows:

constants:
  type: software
  title: lula

  resources:
    name: test-pod-label
    namespace: validation-test
    imagelist:
      - nginx
      - nginx2

Constants will respect the structure of a map[string]interface{} and can be referenced as follows:

# validaiton.yaml
metadata:
  name: sample {{ .const.type }} validation for {{ .const.title }}
domain:
  type: kubernetes
  kubernetes-spec:
    resources:
      - name: myPod
        resource-rule:
          name: {{ .const.resources.name }}
          version: v1
          resource: pods
          namespaces: [{{ .const.resources.namespace }}]
provider:
  type: opa
  opa-spec:
    rego: |
      package validate
      import rego.v1

      validate if {
        input.myPod.metadata.name == {{ .const.resources.name }}
        input.myPod.containers[_].name in { {{ .const.resources.imagelist | concatToRegoList }} }
      }

And will be rendered as:

metadata:
  name: sample software validation for lula
domain:
  type: kubernetes
  kubernetes-spec:
    resources:
      - name: myPod
        resource-rule:
          name: myPod
          version: v1
          resource: pods
          namespaces: [validation-test]
provider:
  type: opa
  opa-spec:
    rego: |
      package validate
      import rego.v1

      validate if {
        input.myPod.metadata.name == "myPod"
        input.myPod.containers[_].image in { "nginx", "nginx2" }
      }

The constant’s keys should be in the format .const.<key> and should not contain any ‘-’ or ‘.’ characters, as this will not respect the go text/template format.

[!IMPORTANT] Due to viper limitations, all constants should be referenced in the template as lowercase values.

Variables

A sample variables section of a lula-config.yaml file is as follows:

variables:
  - key: some_lula_secret
    sensitive: true
  - key: some_env_var
    default: this-should-be-overridden

The variables section is a list of key, default, and sensitive fields, where sensitive and default are optional. The key and default fields are strings, and the sensitive field is a boolean.

A default value can be specified in the case where an environment variable may or may not be set, however an environment variable will always take precedence over a default value.

The environment variable should follow the pattern of LULA_VAR_<key> (not case sensitive), where <key> is the key specified in the variables section.

When using sensitive variables, the default behavior is to mask the value in the output of the template.