Configuration
3 minute read
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
Command Line Flag:
When a setting liketarget
is specified using a command line flag, this value takes the highest precedence, overriding any environment variable or configuration file settings.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.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.
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.
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