feat: allow to load params from file using the paramsFromFile

Signed-off-by: Martin Chodur <[email protected]>

CHANGELOG.md

@@ -7,6 +7,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 - Fixed error messages for the `hasSourceTenantsForMetrics` and `expressionDoesNotUseIrate` validators.
+
+- Added new option `paramsFromFile` to the validators, so the params can be loaded from a YAML file.
+  Example promruval config:
+  ```yaml
+  - type: labelHasAllowedValue
+    paramsFromFile: ./examples/allowed_values_params.yaml
+  ```
+
+  Content of `./examples/allowed_values_params.yaml`:
+  ```yaml
+  label: "severity"
+  allowedValues: ["info", "warning", "critical"]
+  ```
+
 - Added new config option `additionalDetails` to all validators providing  possibility to add custom details about the error and how to solve it.
   Those will be appended to the validator error message in a parenthesis if provided.
   Example configuration:

README.md

@@ -156,9 +156,13 @@ validationRules:
       - type: hasLabels
         # Additional detaild that will be appended to the default error message. Useful to customize the error message.
         additionalDetails: "We do this because ..."
-        # Parameters of the validation.
+        # Parameters of the validation. See the /docs/validations.md for details on params of each validation.
         params:
           labels: [ "severity" ]
+        # OPTIONAL If you want to load the parameters from a separate file, you can use this option.
+        # The content of the file must be in the exact form as the expected params would be.
+        # The option is mutually exclusive with the `params` option.
+        # paramsFromFile: /path/to/file.yaml
       ...
 ```
 

examples/allowed_values_params.yaml

@@ -0,0 +1,2 @@
+label: "severity"
+allowedValues: ["info", "warning", "critical"]

examples/validation.yaml

@@ -12,9 +12,7 @@ validationRules:
         params:
           labels: ["severity"]
       - type: labelHasAllowedValue
-        params:
-          label: "severity"
-          allowedValues: ["info", "warning", "critical"]
+        paramsFromFile: ./examples/allowed_values_params.yaml
       - type: exclusiveLabels
         params:
           firstLabel: severity

pkg/config/config.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"fmt"
+	"os"
 	"time"
 
 	"gopkg.in/yaml.v3"
@@ -57,6 +58,29 @@ type ValidatorConfig struct {
 	ValidatorType     string    `yaml:"type"`
 	AdditionalDetails string    `yaml:"additionalDetails"`
 	Params            yaml.Node `yaml:"params"`
+	ParamsFromFile    string    `yaml:"paramsFromFile"`
+}
+
+func (c *ValidatorConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	type plain ValidatorConfig
+	err := unmarshal((*plain)(c))
+	if err != nil {
+		return err
+	}
+	if c.ParamsFromFile != "" {
+		if !c.Params.IsZero() {
+			return fmt.Errorf("cannot use both `params` and `paramsFromFile`")
+		}
+		fileData, err := os.ReadFile(c.ParamsFromFile)
+		if err != nil {
+			return fmt.Errorf("cannot read params from file %s: %w", c.ParamsFromFile, err)
+		}
+		err = yaml.Unmarshal(fileData, &c.Params)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 type ValidationScope string