fix ennvar expansion in configuration file

cmd/root.go

@@ -1,7 +1,6 @@
 package cmd
 
 import (
-	"bytes"
 	"context"
 	"flag"
 	"fmt"
@@ -20,8 +19,10 @@ import (
 
 	csbouncer "github.com/crowdsecurity/go-cs-bouncer"
 	"github.com/crowdsecurity/go-cs-lib/csdaemon"
+	"github.com/crowdsecurity/go-cs-lib/csstring"
 	"github.com/crowdsecurity/go-cs-lib/version"
 
+
 	"github.com/crowdsecurity/crowdsec/pkg/models"
 
 	"github.com/crowdsecurity/cs-firewall-bouncer/pkg/backend"
@@ -152,17 +153,19 @@ func Execute() error {
 		return fmt.Errorf("configuration file is required")
 	}
 
-	configBytes, err := cfg.MergedConfig(*configPath)
+	configMerged, err := cfg.MergedConfig(*configPath)
 	if err != nil {
 		return fmt.Errorf("unable to read config file: %w", err)
 	}
 
 	if *showConfig {
-		fmt.Println(string(configBytes))
+		fmt.Println(string(configMerged))
 		return nil
 	}
 
-	config, err := cfg.NewConfig(bytes.NewReader(configBytes))
+	configExpanded := csstring.StrictExpand(string(configMerged), os.LookupEnv)
+
+	config, err := cfg.NewConfig(strings.NewReader(configExpanded))
 	if err != nil {
 		return fmt.Errorf("unable to load configuration: %w", err)
 	}
@@ -186,7 +189,7 @@ func Execute() error {
 
 	bouncer := &csbouncer.StreamBouncer{}
 
-	err = bouncer.ConfigReader(bytes.NewReader(configBytes))
+	err = bouncer.ConfigReader(strings.NewReader(configExpanded))
 	if err != nil {
 		return err
 	}

pkg/cfg/config.go

@@ -1,14 +1,13 @@
 package cfg
 
 import (
+	"errors"
 	"fmt"
 	"io"
-	"os"
 
 	log "github.com/sirupsen/logrus"
 	"gopkg.in/yaml.v2"
 
-	"github.com/crowdsecurity/go-cs-lib/csstring"
 	"github.com/crowdsecurity/go-cs-lib/ptr"
 	"github.com/crowdsecurity/go-cs-lib/yamlpatch"
 )
@@ -86,9 +85,7 @@ func NewConfig(reader io.Reader) (*BouncerConfig, error) {
 		return nil, err
 	}
 
-	configBuff := csstring.StrictExpand(string(fcontent), os.LookupEnv)
-
-	err = yaml.Unmarshal([]byte(configBuff), &config)
+	err = yaml.Unmarshal(fcontent, &config)
 	if err != nil {
 		return nil, fmt.Errorf("failed to unmarshal: %w", err)
 	}
@@ -98,7 +95,7 @@ func NewConfig(reader io.Reader) (*BouncerConfig, error) {
 	}
 
 	if config.Mode == "" {
-		return nil, fmt.Errorf("config does not contain 'mode'")
+		return nil, errors.New("config does not contain 'mode'")
 	}
 
 	if len(config.SupportedDecisionsTypes) == 0 {
@@ -191,7 +188,7 @@ func nftablesConfig(config *BouncerConfig) error {
 	}
 
 	if !*config.Nftables.Ipv4.Enabled && !*config.Nftables.Ipv6.Enabled {
-		return fmt.Errorf("both IPv4 and IPv6 disabled, doing nothing")
+		return errors.New("both IPv4 and IPv6 disabled, doing nothing")
 	}
 
 	if config.NftablesHooks == nil || len(config.NftablesHooks) == 0 {