feat: introduce YAML configuration

Makefile

@@ -1,5 +1,5 @@
 SHELL := bash
-ARCH ?= arm64
+ARCH ?= amd64
 ADDR ?= 0.0.0.0:8080
 
 generate:
@@ -11,10 +11,12 @@ build:
 	env GOOS=linux GOARCH=${ARCH} go build -o bin/rcond-${ARCH} ./cmd/rcond/main.go
 
 run:
-	source .env && bin/rcond-${ARCH} ${ADDR}
+	bin/rcond-${ARCH} -config config.yaml
 
 dev:
-	RCOND_API_TOKEN=1234567890 go run cmd/rcond/main.go
+	RCOND_ADDR=127.0.0.1:8080 \
+	RCOND_API_TOKEN=1234567890 \
+	go run cmd/rcond/main.go
 
 upload:
 	scp bin/rcond-${ARCH} pi@rpi-test:/home/pi/rcond

README.md

@@ -6,6 +6,7 @@ A simple daemon and REST API to manage:
 - authorized SSH keys through the user's authorized_keys file
 
 ## Requirements
+
 - Make
 - Go 1.19 or later
 - NetworkManager
@@ -50,6 +51,20 @@ All endpoints except `/health` require authentication via an API token passed in
 ### Request/Response Format
 All endpoints use JSON for request and response payloads.
 
+## Configuration
+
+### File
+
+The default config file location is `/etc/rcond/config.yaml`.  
+It can be overwritten by environment variables and flags.  
+
+Example configuration:
+```yaml
+rcond:
+  addr: 0.0.0.0:8080
+  api_token: 1234567890
+```
+
 ### Environment Variables
 
 | Environment Variable | Description                             | Default       |

cmd/rcond/main.go

@@ -3,41 +3,105 @@
 package main
 
 import (
+	"flag"
 	"fmt"
 	"log"
 	"os"
 
+	"github.com/0x1d/rcond/pkg/config"
 	http "github.com/0x1d/rcond/pkg/http"
 )
 
-const (
-	NETWORK_CONNECTION_UUID = "7d706027-727c-4d4c-a816-f0e1b99db8ab"
-)
-
 func usage() {
-	fmt.Printf("Usage: %s <address>\n", os.Args[0])
-	os.Exit(0)
+	fmt.Println("Usage: rcond <flags>")
+	flag.PrintDefaults()
 }
 
 func main() {
-
-	addr := os.Getenv("RCOND_ADDR")
-	if addr == "" {
-		addr = "0.0.0.0:8080"
-	}
-	if len(os.Args) > 1 {
-		addr = os.Args[1]
-	}
-	apiToken := os.Getenv("RCOND_API_TOKEN")
-	if apiToken == "" {
-		log.Fatal("RCOND_API_TOKEN environment variable not set")
+	appConfig, err := loadConfig()
+	if err != nil {
+		usage()
+		fmt.Printf("\nFailed to load config: %v\n", err)
+		os.Exit(1)
 	}
 
-	srv := http.NewServer(addr, apiToken)
+	srv := http.NewServer(appConfig)
 	srv.RegisterRoutes()
 
-	log.Printf("Starting server on %s", addr)
+	log.Printf("Starting server on %s", appConfig.Rcond.Addr)
 	if err := srv.Start(); err != nil {
 		log.Fatal(err)
 	}
 }
+
+func loadConfig() (*config.Config, error) {
+	configPath := "/etc/rcond/config.yaml"
+	appConfig := &config.Config{}
+	help := false
+
+	flag.StringVar(&configPath, "config", configPath, "Path to the configuration file")
+	flag.StringVar(&appConfig.Rcond.Addr, "addr", "", "Address to bind the HTTP server to")
+	flag.StringVar(&appConfig.Rcond.ApiToken, "token", "", "API token to use for authentication")
+	flag.BoolVar(&help, "help", false, "Show help")
+	flag.Parse()
+
+	if help {
+		usage()
+		os.Exit(0)
+	}
+
+	// Load config from file
+	if _, err := os.Stat(configPath); !os.IsNotExist(err) {
+		configFile, err := config.LoadConfig(configPath)
+		if err != nil {
+			return nil, err
+		}
+		appConfig = configFile
+	}
+
+	// Override config values from environment variables and flags
+	overrideConfigValuesFromEnv(map[string]*string{
+		"RCOND_ADDR":      &appConfig.Rcond.Addr,
+		"RCOND_API_TOKEN": &appConfig.Rcond.ApiToken,
+	})
+
+	overrideConfigValuesFromFlag(map[string]*string{
+		"addr":  &appConfig.Rcond.Addr,
+		"token": &appConfig.Rcond.ApiToken,
+	})
+
+	// Validate required fields
+	if err := validateRequiredFields(map[string]*string{
+		"addr":  &appConfig.Rcond.Addr,
+		"token": &appConfig.Rcond.ApiToken,
+	}); err != nil {
+		return nil, err
+	}
+
+	return appConfig, nil
+}
+
+func overrideConfigValuesFromEnv(envMap map[string]*string) {
+	for varName, configValue := range envMap {
+		if envValue, ok := os.LookupEnv(varName); ok {
+			*configValue = envValue
+		}
+	}
+}
+
+func overrideConfigValuesFromFlag(flagMap map[string]*string) {
+	for flagName, configValue := range flagMap {
+		if flagValue := flag.Lookup(flagName).Value.String(); flagValue != "" {
+			*configValue = flagValue
+		}
+	}
+}
+
+func validateRequiredFields(fields map[string]*string) error {
+	for name, value := range fields {
+		if *value == "" {
+			return fmt.Errorf("%s is required", name)
+		}
+	}
+	return nil
+}

config.yaml

@@ -0,0 +1,3 @@
+rcond:
+  addr: 0.0.0.0:8080
+  api_token: 1234567890

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/google/uuid v1.6.0
 	github.com/gorilla/mux v1.8.1
 	golang.org/x/crypto v0.37.0
+	gopkg.in/yaml.v3 v3.0.1
 )
 
 require golang.org/x/sys v0.32.0 // indirect

go.sum

@@ -10,3 +10,7 @@ golang.org/x/sys v0.32.0 h1:s77OFDvIQeibCmezSnk/q6iAfkdiQaJi4VzroCFrN20=
 golang.org/x/sys v0.32.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
 golang.org/x/term v0.31.0 h1:erwDkOK1Msy6offm1mOgvspSkslFnIGsFnxOKoufg3o=
 golang.org/x/term v0.31.0/go.mod h1:R4BeIy7D95HzImkxGkTW1UQTtP54tio2RyHz7PwK0aw=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

install/rcond.service

@@ -0,0 +1,13 @@
+[Unit]
+Description=rcond service
+After=network.target
+
+[Service]
+Type=simple
+User=root
+WorkingDirectory=/path/to/your/rcond
+ExecStart=/path/to/your/rcond/bin/rcond-${ARCH} ${ADDR}
+Restart=on-failure
+
+[Install]
+WantedBy=multi-user.target

pkg/config/config.go

@@ -0,0 +1,38 @@
+package config
+
+import (
+	"os"
+
+	"gopkg.in/yaml.v3"
+)
+
+type Config struct {
+	Rcond RcondConfig `yaml:"rcond"`
+}
+
+type RcondConfig struct {
+	Addr     string `yaml:"addr"`
+	ApiToken string `yaml:"api_token"`
+}
+
+func LoadConfig(path string) (*Config, error) {
+	yamlFile, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	var config Config
+	err = yaml.Unmarshal(yamlFile, &config)
+	if err != nil {
+		return nil, err
+	}
+	return &config, nil
+}
+
+func SaveConfig(path string, config *Config) error {
+	yamlFile, err := yaml.Marshal(config)
+	if err != nil {
+		return err
+	}
+	return os.WriteFile(path, yamlFile, 0644)
+}

pkg/http/server.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"time"
 
+	"github.com/0x1d/rcond/pkg/config"
 	"github.com/gorilla/mux"
 )
 
@@ -15,11 +16,15 @@ type Server struct {
 	apiToken string
 }
 
-func NewServer(addr string, apiToken string) *Server {
+func NewServer(cfg *config.Config) *Server {
+	if cfg.Rcond.Addr == "" || cfg.Rcond.ApiToken == "" {
+		panic("addr or api_token is not set")
+	}
+
 	router := mux.NewRouter()
 
 	srv := &http.Server{
-		Addr:         addr,
+		Addr:         cfg.Rcond.Addr,
 		Handler:      router,
 		ReadTimeout:  15 * time.Second,
 		WriteTimeout: 15 * time.Second,
@@ -28,7 +33,7 @@ func NewServer(addr string, apiToken string) *Server {
 	return &Server{
 		router:   router,
 		srv:      srv,
-		apiToken: apiToken,
+		apiToken: cfg.Rcond.ApiToken,
 	}
 }