feat: add support for jsonnet config file format

.github/workflows/go.yaml

@@ -23,6 +23,7 @@ jobs:
       - name: Golangci-lint
         uses: golangci/golangci-lint-action@v6
         with:
+          version: "v1.62.2"
           args: --timeout 5m0s
 
       - name: Build

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [3.6.0] - 2024-11-29
+- Added: Configuration file can now be in Jsonnet format if the config file name ends with `.jsonnet` and it will get automatically evaluated.
+
 ## [3.5.0] - 2024-10-31
 - 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)

Makefile

@@ -23,7 +23,7 @@ build:
 	GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -o $(PROMRUVAL_BIN)
 
 E2E_TESTS_VALIDATIONS_FILE := examples/validation.yaml
-E2E_TESTS_ADDITIONAL_VALIDATIONS_FILE := examples/additional-validation.yaml
+E2E_TESTS_ADDITIONAL_VALIDATIONS_FILE := examples/additional-validation.jsonnet
 E2E_TESTS_RULES_FILES := examples/rules/*
 E2E_TESTS_DOCS_FILE_MD := examples/human_readable.md
 E2E_TESTS_DOCS_FILE_HTML := examples/human_readable.html

README.md

@@ -107,6 +107,8 @@ validation-docs [<flags>]
 Promruval supports the default YAML format (`.yaml` or `.yml`) of rule files but also supports rules written in [Jsonnet](https://jsonnet.org/) (`.jsonnet`).
 If will be rendered using the [go-jsonnet](https://github.com/google/go-jsonnet) library and then validated as usual, so you don't have to evaluate those by yourself before running the validation.
 
+Additionaly it supports also the configuration file in the Jsonnet format.
+
 #### Configuration composition
 
 The `--config-file` flag can be passed multiple times. Promruval will append the additional validation rules from the
@@ -134,7 +136,7 @@ promruval validate --config-file ./rules/validation.yaml --config-file ./rules/p
 
 ### Configuration
 
-Promruval uses a yaml configuration file to define the validation rules.
+Promruval uses a yaml or jsonnet (if config file ends with `.jsonnet`) configuration file to define the validation rules.
 
 Basic structure is:
 

examples/additional-validation.jsonnet

@@ -0,0 +1,10 @@
+{
+  validationRules:
+    [
+      {
+        name: "another-checks",
+        scope: "All rules",
+        validations: [{ type: "nonEmptyLabels" }],
+      },
+    ],
+}

pkg/config/config.go

@@ -2,14 +2,17 @@ package config
 
 import (
 	"fmt"
+	"io"
 	"os"
 	"path"
+	"strings"
 	"sync"
 	"time"
 
 	"gopkg.in/yaml.v3"
 
 	"github.com/creasty/defaults"
+	"github.com/google/go-jsonnet"
 )
 
 const (
@@ -48,6 +51,7 @@ type Loader struct {
 }
 
 func (l *Loader) Load() (*Config, error) {
+	var configFile io.ReadCloser
 	configFile, err := os.Open(l.ConfigPath)
 	if err != nil {
 		return nil, fmt.Errorf("open config file: %w", err)
@@ -59,6 +63,17 @@ func (l *Loader) Load() (*Config, error) {
 		configDirMtx.Unlock()
 	}()
 	validationConfig := Config{}
+
+	// If the config file is a jsonnet file, evaluate it first
+	if strings.HasSuffix(l.ConfigPath, ".jsonnet") {
+		jsonnetVM := jsonnet.MakeVM()
+		jsonStr, err := jsonnetVM.EvaluateFile(l.ConfigPath)
+		if err != nil {
+			return nil, fmt.Errorf("evaluating jsonnet in config file %s: %w", l.ConfigPath, err)
+		}
+		configFile = io.NopCloser(strings.NewReader(jsonStr))
+	}
+
 	decoder := yaml.NewDecoder(configFile)
 	decoder.KnownFields(true)
 	if err := decoder.Decode(&validationConfig); err != nil {

pkg/validator/promql_expression.go

@@ -277,7 +277,11 @@ func (h validFunctionsOnCounters) Validate(_ unmarshaler.RuleGroup, rule rulefmt
 			}
 			for _, ch := range parser.Children(n) {
 				if m, ok := ch.(*parser.MatrixSelector); ok {
-					if !match.MatchString(m.VectorSelector.(*parser.VectorSelector).Name) {
+					vs, ok := m.VectorSelector.(*parser.VectorSelector)
+					if !ok {
+						continue
+					}
+					if !match.MatchString(vs.Name) {
 						errs = append(errs, fmt.Errorf("`%s` function should be used only on counters and those should end with the `_total` suffix, which is not this case `%s`", v.Func.Name, n.String()))
 					}
 				}