feat: ENV expansion, source tenants scoped cache, structured logging (#…

…90)

Signed-off-by: Martin Chodur <m.chodur@seznam.cz>

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 - Fixed: Ignore white spaces around rule names in the `disabled_validation_rules` annotation CSV format (Thanks @jmichalek13 !)
+- Added: Support ENV expansion in the config file in format `$ENV_VAR` or `${ENV_VAR}`
+- Changed: The cache format is now scoped by source tenants (internal change, no action required)
+- Changed: Logging uses structured logs now
+- Added: new `httpHeaders` field in the `prometheus` section of the config to set custom headers in the Prometheus requests
 
 ## [3.3.0] - 2024-10-03
 - Changed: Upgrade to go 1.23

README.md

@@ -135,6 +135,7 @@ promruval validate --config-file ./rules/validation.yaml --config-file ./rules/p
 ### Configuration
 
 Promruval uses a yaml configuration file to define the validation rules.
+
 Basic structure is:
 
 ```yaml
@@ -159,6 +160,9 @@ prometheus:
   queryOffset: 1m
   # OPTIONAL how long into the past to look in queries supporting time range (just metadata queries for now).
   queryLookback: 20m
+  # OPTIONAL HTTP headers to be added to the request
+  httpHeaders:
+    foo: bar
 
 validationRules:
   # Name of the validation rule.
@@ -186,6 +190,9 @@ 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

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path"
+	"strings"
 	"sync"
 	"time"
 
@@ -48,7 +49,7 @@ type Loader struct {
 }
 
 func (l *Loader) Load() (*Config, error) {
-	configFile, err := os.Open(l.ConfigPath)
+	configFileData, err := os.ReadFile(l.ConfigPath)
 	if err != nil {
 		return nil, fmt.Errorf("open config file: %w", err)
 	}
@@ -58,7 +59,8 @@ func (l *Loader) Load() (*Config, error) {
 		configDirMtx.Unlock()
 	}()
 	validationConfig := Config{}
-	decoder := yaml.NewDecoder(configFile)
+	expandedConfigFileData := os.ExpandEnv(string(configFileData))
+	decoder := yaml.NewDecoder(strings.NewReader(expandedConfigFileData))
 	decoder.KnownFields(true)
 	if err := decoder.Decode(&validationConfig); err != nil {
 		return nil, fmt.Errorf("loading config file: %w", err)
@@ -74,14 +76,15 @@ type Config struct {
 }
 
 type PrometheusConfig struct {
-	URL                   string        `yaml:"url"`
-	Timeout               time.Duration `yaml:"timeout" default:"30s"`
-	InsecureSkipTLSVerify bool          `yaml:"insecureSkipTlsVerify"`
-	CacheFile             string        `yaml:"cacheFile,omitempty" default:".promruval_cache.json"`
-	MaxCacheAge           time.Duration `yaml:"maxCacheAge,omitempty" default:"1h"`
-	BearerTokenFile       string        `yaml:"bearerTokenFile,omitempty"`
-	QueryOffset           time.Duration `yaml:"queryOffset,omitempty" default:"1m"`
-	QueryLookback         time.Duration `yaml:"queryLookback,omitempty" default:"20m"`
+	URL                   string            `yaml:"url"`
+	Timeout               time.Duration     `yaml:"timeout" default:"30s"`
+	InsecureSkipTLSVerify bool              `yaml:"insecureSkipTlsVerify"`
+	CacheFile             string            `yaml:"cacheFile,omitempty" default:".promruval_cache.json"`
+	MaxCacheAge           time.Duration     `yaml:"maxCacheAge,omitempty" default:"1h"`
+	BearerTokenFile       string            `yaml:"bearerTokenFile,omitempty"`
+	QueryOffset           time.Duration     `yaml:"queryOffset,omitempty" default:"1m"`
+	QueryLookback         time.Duration     `yaml:"queryLookback,omitempty" default:"20m"`
+	HTTPHeaders           map[string]string `yaml:"httpHeaders,omitempty"`
 }
 
 func (c *PrometheusConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {

pkg/prometheus/cache.go

@@ -10,43 +10,49 @@ import (
 
 func newCache(file, prometheusURL string, maxAge time.Duration) *cache {
 	emptyCache := cache{
-		file:                   file,
-		PrometheusURL:          prometheusURL,
-		Created:                time.Now(),
-		QueriesStats:           make(map[string]queryStats),
-		KnownLabels:            []string{},
-		SelectorMatchingSeries: make(map[string]int),
+		file:          file,
+		PrometheusURL: prometheusURL,
+		Created:       time.Now(),
+		SourceTenants: make(map[string]*cacheData),
 	}
 	previousCache := emptyCache
 	f, err := os.Open(file)
 	if err != nil {
 		if !os.IsNotExist(err) {
 			f, err = os.Create(file)
 			if err != nil {
-				log.Warnf("error creating cache file %s: %s", file, err)
+				log.WithError(err).WithField("file", file).Warn("error creating cache file")
 				return &emptyCache
 			}
 		} else {
-			log.Warnf("error opening cache file %s, skipping: %s", file, err)
+			log.WithError(err).WithField("file", file).Warn("error opening cache file, skipping")
 			return &emptyCache
 		}
 	}
 	if err := json.NewDecoder(f).Decode(&previousCache); err != nil {
-		log.Warnf("invalid cache file `%s` format: %s", file, err)
+		log.WithError(err).WithField("file", file).Warn("invalid cache file format")
 		return &emptyCache
 	}
 	pruneCache := false
 	cacheAge := time.Since(previousCache.Created)
 	if maxAge != 0 && cacheAge > maxAge {
-		log.Infof("%s old cache %s is outdated, limit is %s", cacheAge, file, maxAge)
+		log.WithFields(log.Fields{
+			"cacheAge":    cacheAge,
+			"maxCacheAge": maxAge,
+			"file_name":   file,
+		}).Info("cache is outdated")
 		pruneCache = true
 	}
 	if previousCache.PrometheusURL != prometheusURL {
-		log.Infof("data in cache file %s are from different Prometheus on URL %s, cannot be used for the instance on %s URL", file, previousCache.PrometheusURL, prometheusURL)
+		log.WithFields(log.Fields{
+			"previousPrometheusURL": previousCache.PrometheusURL,
+			"newPrometheusURL":      prometheusURL,
+			"file_name":             file,
+		}).Info("data in cache file are from different Prometheus, cannot be used")
 		pruneCache = true
 	}
 	if pruneCache {
-		log.Warnf("Pruning cache file %s", file)
+		log.WithField("file", file).Warn("Pruning cache file")
 		return &emptyCache
 	}
 	return &previousCache
@@ -57,30 +63,48 @@ type queryStats struct {
 	Series   int           `json:"series"`
 	Duration time.Duration `json:"duration"`
 }
-type cache struct {
-	file                   string
-	PrometheusURL          string                `json:"prometheus_url"`
-	Created                time.Time             `json:"created"`
+
+type cacheData struct {
 	QueriesStats           map[string]queryStats `json:"queries_stats"`
 	KnownLabels            []string              `json:"known_labels"`
 	SelectorMatchingSeries map[string]int        `json:"selector_matching_series"`
 }
+type cache struct {
+	file          string
+	PrometheusURL string                `json:"prometheus_url"`
+	Created       time.Time             `json:"created"`
+	SourceTenants map[string]*cacheData `json:"source_tenants"`
+}
+
+func (c *cache) SourceTenantsData(sourceTenants []string) *cacheData {
+	key := sourceTenantsToHeader(sourceTenants)
+	data, found := c.SourceTenants[key]
+	if !found {
+		data = &cacheData{
+			QueriesStats:           make(map[string]queryStats),
+			SelectorMatchingSeries: make(map[string]int),
+			KnownLabels:            []string{},
+		}
+		c.SourceTenants[key] = data
+	}
+	return data
+}
 
 func (c *cache) Dump() {
 	f, err := os.Create(c.file)
 	if err != nil {
-		log.Warnf("failed to create cache file %s: %s", c.file, err)
+		log.WithError(err).WithField("file", c.file).Warn("failed to create cache file")
 		return
 	}
 	defer func(f *os.File) {
 		_ = f.Close()
 	}(f)
 	e := json.NewEncoder(f)
-	e.SetIndent("", "  ")
+	e.SetIndent("", "")
 	err = e.Encode(c)
 	if err != nil {
-		log.Warnf("failed to write cache data: %s", err)
+		log.WithError(err).Warn("failed to write cache data")
 		return
 	}
-	log.Infof("successfully dumped cache to file %s", c.file)
+	log.WithField("file_name", c.file).Info("successfully dumped cache to file")
 }