fix: revert ENV expansion in the config file

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

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 - Added: New validation `expressionDoesNotUseClassicHistogramBucketOperations` to avoid queries fragile because of the classic histogram bucket operations.
   See the docs for more info [expressionDoesNotUseClassicHistogramBucketOperations](docs/validations.md#expressiondoesnotuseclassichistogrambucketoperations)
+- Changed: :warning: revert the ENV expansion in config file since it was breaking and caused issues (it was a stupid idea)
 
 ## [3.4.0] - 2024-10-30
 - Fixed: :warning: Ignore white spaces around rule names in the `disabled_validation_rules` annotation CSV format (Thanks @jmichalek13 !)

README.md

@@ -190,9 +190,6 @@ For a complete list of supported validations see the [docs/validations.md](docs/
 
 If you want to see example configuration see the  [`examples/validation.yaml`](examples/validation.yaml).
 
-#### ENV expansion
-You can use ENV variable expansion in the configuration file. Just use the `$ENV` or `${ENV_VAR}` syntax and it will be replaced with the value of the `ENV_VAR` environment variable.
-
 ### How to run it
 
 If you downloaded the [prebuilt binary](https://github.com/FUSAKLA/promruval/releases/latest) or built it on your own:

pkg/config/config.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"os"
 	"path"
-	"strings"
 	"sync"
 	"time"
 
@@ -49,18 +48,18 @@ type Loader struct {
 }
 
 func (l *Loader) Load() (*Config, error) {
-	configFileData, err := os.ReadFile(l.ConfigPath)
+	configFile, err := os.Open(l.ConfigPath)
 	if err != nil {
 		return nil, fmt.Errorf("open config file: %w", err)
 	}
+	defer configFile.Close()
 	configDirMtx.Lock()
 	configDir = path.Dir(l.ConfigPath)
 	defer func() {
 		configDirMtx.Unlock()
 	}()
 	validationConfig := Config{}
-	expandedConfigFileData := os.ExpandEnv(string(configFileData))
-	decoder := yaml.NewDecoder(strings.NewReader(expandedConfigFileData))
+	decoder := yaml.NewDecoder(configFile)
 	decoder.KnownFields(true)
 	if err := decoder.Decode(&validationConfig); err != nil {
 		return nil, fmt.Errorf("loading config file: %w", err)