Add -config flag using cobra to specify config file path

cmd/pixad/main.go

@@ -2,6 +2,10 @@
 package main
 
 import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
 	"go.uber.org/fx"
 	"sneak.berlin/go/pixa/internal/config"
 	"sneak.berlin/go/pixa/internal/database"
@@ -19,11 +23,33 @@ var (
 	Buildarch string    //nolint:gochecknoglobals // set by ldflags
 )
 
+var configPath string //nolint:gochecknoglobals // cobra flag
+
 func main() {
+	rootCmd := &cobra.Command{
+		Use:   "pixad",
+		Short: "Pixa image caching proxy server",
+		Run:   run,
+	}
+
+	rootCmd.Flags().StringVarP(&configPath, "config", "c", "", "path to config file")
+
+	if err := rootCmd.Execute(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func run(_ *cobra.Command, _ []string) {
 	globals.Appname = Appname
 	globals.Version = Version
 	globals.Buildarch = Buildarch
 
+	// Set config path in environment if specified via flag
+	if configPath != "" {
+		_ = os.Setenv("PIXA_CONFIG_PATH", configPath)
+	}
+
 	fx.New(
 		fx.Provide(
 			config.New,

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/go-chi/cors v1.2.2
 	github.com/prometheus/client_golang v1.23.2
 	github.com/slok/go-http-metrics v0.13.0
+	github.com/spf13/cobra v1.10.2
 	go.uber.org/fx v1.24.0
 	golang.org/x/image v0.34.0
 	modernc.org/sqlite v1.42.2
@@ -85,6 +86,7 @@ require (
 	github.com/hashicorp/hcl v1.0.1-vault-7 // indirect
 	github.com/hashicorp/serf v0.10.1 // indirect
 	github.com/hashicorp/vault/api v1.20.0 // indirect
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/kylelemons/godebug v1.1.0 // indirect

go.sum

@@ -85,6 +85,7 @@ github.com/coreos/go-semver v0.3.1 h1:yi21YpKnrx1gt5R+la8n5WgS0kCrsPp33dmEyHReZr
 github.com/coreos/go-semver v0.3.1/go.mod h1:irMmmIw/7yzSRPWryHsK7EYSg09caPQL03VsM8rvUec=
 github.com/coreos/go-systemd/v22 v22.5.0 h1:RrqgGjYQKalulkV8NGVIfkXQf6YYmOyiJKk8iXXhfZs=
 github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
+github.com/cpuguy83/go-md2man/v2 v2.0.6/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -228,6 +229,8 @@ github.com/hashicorp/serf v0.10.1 h1:Z1H2J60yRKvfDYAOZLd2MU0ND4AH/WDz7xYHDWQsIPY
 github.com/hashicorp/serf v0.10.1/go.mod h1:yL2t6BqATOLGc5HF7qbFkTfXoPIY0WZdWHfEvMqbG+4=
 github.com/hashicorp/vault/api v1.20.0 h1:KQMHElgudOsr+IbJgmbjHnCTxEpKs9LnozA1D3nozU4=
 github.com/hashicorp/vault/api v1.20.0/go.mod h1:GZ4pcjfzoOWpkJ3ijHNpEoAxKEsBJnVljyTe3jM2Sms=
+github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
+github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
 github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
@@ -340,6 +343,7 @@ github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
 github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=
 github.com/rogpeppe/go-internal v1.13.1/go.mod h1:uMEvuHeurkdAXX61udpOXGD/AzZDWNMNyH2VO9fmH0o=
+github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/ryanuber/columnize v0.0.0-20160712163229-9b3edd62028f/go.mod h1:sm1tb6uqfes/u+d4ooFouqFdy9/2g9QGwK3SQygK0Ts=
 github.com/ryanuber/columnize v2.1.0+incompatible/go.mod h1:sm1tb6uqfes/u+d4ooFouqFdy9/2g9QGwK3SQygK0Ts=
 github.com/ryanuber/go-glob v1.0.0 h1:iQh3xXAumdQ+4Ufa5b25cRpC5TYKlno6hsv6Cb3pkBk=
@@ -350,6 +354,9 @@ github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPx
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
 github.com/slok/go-http-metrics v0.13.0 h1:lQDyJJx9wKhmbliyUsZ2l6peGnXRHjsjoqPt5VYzcP8=
 github.com/slok/go-http-metrics v0.13.0/go.mod h1:HIr7t/HbN2sJaunvnt9wKP9xoBBVZFo1/KiHU3b0w+4=
+github.com/spf13/cobra v1.10.2 h1:DMTTonx5m65Ic0GOoRY2c16WCbHxOOw6xxezuLaBpcU=
+github.com/spf13/cobra v1.10.2/go.mod h1:7C1pvHqHw5A4vrJfjNwvOdzYu0Gml16OCs2GRiTUUS4=
+github.com/spf13/pflag v1.0.9/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/spf13/pflag v1.0.10 h1:4EBh2KAYBwaONj6b2Ye1GiHfwjqyROoF4RwYO+vPwFk=
 github.com/spf13/pflag v1.0.10/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
@@ -413,6 +420,7 @@ go.uber.org/zap v1.27.0 h1:aJMhYGrd5QSmlpLMr2MftRKl7t8J8PTZPA732ud/XR8=
 go.uber.org/zap v1.27.0/go.mod h1:GB2qFLM7cTU87MWRP2mPIjqfIDnGu+VIO4V/SdhGo2E=
 go.yaml.in/yaml/v2 v2.4.2 h1:DzmwEr2rDGHl7lsFgAHxmNz/1NlQ7xLIrlN2h5d1eGI=
 go.yaml.in/yaml/v2 v2.4.2/go.mod h1:081UH+NErpNdqlCXm3TtEran0rJZGxAYx9hb/ELlsPU=
+go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190923035154-9ee001bba392/go.mod h1:/lpIB1dKB+9EgE3H3cr1v9wB50oz8l4C4h62xy7jSTY=

internal/config/config.go

@@ -3,6 +3,7 @@ package config
 
 import (
 	"fmt"
+	"log/slog"
 	"os"
 	"path/filepath"
 	"strings"
@@ -48,29 +49,9 @@ func New(_ fx.Lifecycle, params Params) (*Config, error) {
 	log := params.Logger.Get()
 	name := params.Globals.Appname
 
-	var sc *smartconfig.Config
+	sc, err := loadConfigFile(log, name)
-	var err error
+	if err != nil {
-
+		return nil, err
-	// Try loading config from standard locations
-	configPaths := []string{
-		fmt.Sprintf("/etc/%s/config.yml", name),
-		fmt.Sprintf("/etc/%s/config.yaml", name),
-		filepath.Join(os.Getenv("HOME"), ".config", name, "config.yml"),
-		filepath.Join(os.Getenv("HOME"), ".config", name, "config.yaml"),
-		"config.yml",
-		"config.yaml",
-	}
-
-	for _, path := range configPaths {
-		if _, statErr := os.Stat(path); statErr == nil {
-			sc, err = smartconfig.NewFromConfigPath(path)
-			if err == nil {
-				log.Info("loaded config file", "path", path)
-
-				break
-			}
-			log.Warn("failed to parse config file", "path", path, "error", err)
-		}
 	}
 
 	if sc == nil {
@@ -103,6 +84,48 @@ func New(_ fx.Lifecycle, params Params) (*Config, error) {
 	return c, nil
 }
 
+// loadConfigFile loads configuration from PIXA_CONFIG_PATH env var or standard locations.
+func loadConfigFile(log *slog.Logger, appName string) (*smartconfig.Config, error) {
+	// Check for explicit config path from environment
+	if envPath := os.Getenv("PIXA_CONFIG_PATH"); envPath != "" {
+		sc, err := smartconfig.NewFromConfigPath(envPath)
+		if err != nil {
+			return nil, fmt.Errorf("failed to load config from %s: %w", envPath, err)
+		}
+
+		log.Info("loaded config file", "path", envPath)
+
+		return sc, nil
+	}
+
+	// Try loading config from standard locations
+	configPaths := []string{
+		fmt.Sprintf("/etc/%s/config.yml", appName),
+		fmt.Sprintf("/etc/%s/config.yaml", appName),
+		filepath.Join(os.Getenv("HOME"), ".config", appName, "config.yml"),
+		filepath.Join(os.Getenv("HOME"), ".config", appName, "config.yaml"),
+		"config.yml",
+		"config.yaml",
+	}
+
+	for _, path := range configPaths {
+		if _, statErr := os.Stat(path); statErr == nil {
+			sc, err := smartconfig.NewFromConfigPath(path)
+			if err != nil {
+				log.Warn("failed to parse config file", "path", path, "error", err)
+
+				continue
+			}
+
+			log.Info("loaded config file", "path", path)
+
+			return sc, nil
+		}
+	}
+
+	return nil, nil //nolint:nilnil // nil config is valid (use defaults)
+}
+
 func getString(sc *smartconfig.Config, key, defaultVal string) string {
 	if sc == nil {
 		return defaultVal