Use CLI flags parser from Icinga Go Library

cmd/icinga-notifications/main.go

@@ -2,8 +2,6 @@ package main
 
 import (
 	"context"
-	"flag"
-	"fmt"
 	"github.com/icinga/icinga-go-library/database"
 	"github.com/icinga/icinga-go-library/logging"
 	"github.com/icinga/icinga-go-library/utils"
@@ -16,45 +14,18 @@ import (
 	"github.com/icinga/icinga-notifications/internal/listener"
 	"github.com/icinga/icinga-notifications/internal/object"
 	"github.com/okzk/sdnotify"
-	"os"
 	"os/signal"
-	"runtime"
 	"syscall"
 	"time"
 )
 
 func main() {
-	var configPath string
-	var showVersion bool
-
-	flag.StringVar(&configPath, "config", internal.SysConfDir+"/icinga-notifications/config.yml", "path to config file")
-	flag.BoolVar(&showVersion, "version", false, "print version")
-	flag.Parse()
-
-	if showVersion {
-		// reuse internal.Version.print() once the project name is configurable
-		fmt.Println("Icinga Notifications version:", internal.Version.Version)
-		fmt.Println()
-
-		fmt.Println("Build information:")
-		fmt.Printf("  Go version: %s (%s, %s)\n", runtime.Version(), runtime.GOOS, runtime.GOARCH)
-		if internal.Version.Commit != "" {
-			fmt.Println("  Git commit:", internal.Version.Commit)
-		}
-		return
-	}
-
-	err := daemon.LoadConfig(configPath)
-	if err != nil {
-		_, _ = fmt.Fprintln(os.Stderr, "cannot load config:", err)
-		os.Exit(1)
-	}
-
+	daemon.ParseFlagsAndConfig()
 	conf := daemon.Config()
 
 	logs, err := logging.NewLoggingFromConfig("icinga-notifications", conf.Logging)
 	if err != nil {
-		utils.PrintErrorThenExit(err, 1)
+		utils.PrintErrorThenExit(err, daemon.ExitFailure)
 	}
 
 	logger := logs.GetLogger()

go.mod

@@ -6,10 +6,9 @@ require (
 	github.com/creasty/defaults v1.7.0
 	github.com/emersion/go-sasl v0.0.0-20231106173351-e73c9f7bad43
 	github.com/emersion/go-smtp v0.21.3
-	github.com/goccy/go-yaml v1.11.3
 	github.com/google/uuid v1.6.0
 	github.com/hashicorp/golang-lru/v2 v2.0.7
-	github.com/icinga/icinga-go-library v0.2.0
+	github.com/icinga/icinga-go-library v0.3.0
 	github.com/jhillyerd/enmime v1.2.0
 	github.com/jmoiron/sqlx v1.4.0
 	github.com/okzk/sdnotify v0.0.0-20180710141335-d9becc38acbd
@@ -27,6 +26,7 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fatih/color v1.13.0 // indirect
 	github.com/go-sql-driver/mysql v1.8.1 // indirect
+	github.com/goccy/go-yaml v1.11.3 // indirect
 	github.com/gogs/chardet v0.0.0-20211120154057-b7413eaefb8f // indirect
 	github.com/jaytaylor/html2text v0.0.0-20230321000545-74c2419ad056 // indirect
 	github.com/jessevdk/go-flags v1.5.0 // indirect

go.sum

@@ -33,8 +33,8 @@ github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
 github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
-github.com/icinga/icinga-go-library v0.2.0 h1:1or5s3KMEJGdhFbMzlN8NPw1NCd/3ntsKLw5et4/9XI=
-github.com/icinga/icinga-go-library v0.2.0/go.mod h1:YN7XJN3W0FodD+j4kirO89zk2tgvanXWt1RMV8UgOLo=
+github.com/icinga/icinga-go-library v0.3.0 h1:BeoomAiQC5RTRWCNqNkgbdTGxQ7ZFfkruR4HCSn5e0k=
+github.com/icinga/icinga-go-library v0.3.0/go.mod h1:YN7XJN3W0FodD+j4kirO89zk2tgvanXWt1RMV8UgOLo=
 github.com/jaytaylor/html2text v0.0.0-20230321000545-74c2419ad056 h1:iCHtR9CQyktQ5+f3dMVZfwD2KWJUgm7M0gdL9NGr8KA=
 github.com/jaytaylor/html2text v0.0.0-20230321000545-74c2419ad056/go.mod h1:CVKlgaMiht+LXvHG173ujK6JUhZXKb2u/BQtjPDIvyk=
 github.com/jessevdk/go-flags v1.5.0 h1:1jKYvbxEjfUl0fmqTCOfonvskHHXMjBySTLW4y9LFvc=

internal/daemon/config.go

@@ -3,14 +3,20 @@ package daemon
 import (
 	"errors"
 	"github.com/creasty/defaults"
-	"github.com/goccy/go-yaml"
+	"github.com/icinga/icinga-go-library/config"
 	"github.com/icinga/icinga-go-library/database"
 	"github.com/icinga/icinga-go-library/logging"
+	"github.com/icinga/icinga-go-library/utils"
 	"github.com/icinga/icinga-notifications/internal"
 	"os"
 	"time"
 )
 
+const (
+	ExitSuccess = 0
+	ExitFailure = 1
+)
+
 type ConfigFile struct {
 	Listen        string          `yaml:"listen" default:"localhost:5680"`
 	DebugPassword string          `yaml:"debug-password"`
@@ -28,65 +34,70 @@ func (c *ConfigFile) SetDefaults() {
 	}
 }
 
-// Assert interface compliance.
-var _ defaults.Setter = (*ConfigFile)(nil)
-
-// config holds the configuration state as a singleton. It is used from LoadConfig and Config
-var config *ConfigFile
-
-// LoadConfig loads the daemon config from given path. Call it only once when starting the daemon.
-func LoadConfig(path string) error {
-	if config != nil {
-		return errors.New("config already set")
+// Validate implements the config.Validator interface.
+// Validates the entire daemon configuration on daemon startup.
+func (c *ConfigFile) Validate() error {
+	if err := c.Database.Validate(); err != nil {
+		return err
 	}
-
-	cfg, err := fromFile(path)
-	if err != nil {
+	if err := c.Logging.Validate(); err != nil {
 		return err
 	}
 
-	config = cfg
-
 	return nil
 }
 
-// Config returns the config that was loaded while starting the daemon
-func Config() *ConfigFile {
-	return config
+// Assert interface compliance.
+var (
+	_ defaults.Setter  = (*ConfigFile)(nil)
+	_ config.Validator = (*ConfigFile)(nil)
+)
+
+// Flags defines the CLI flags supported by Icinga Notifications.
+type Flags struct {
+	// Version decides whether to just print the version and exit.
+	Version bool `long:"version" description:"print version and exit"`
+	// Config is the path to the config file
+	Config string `short:"c" long:"config" description:"path to config file"`
 }
 
-func fromFile(path string) (*ConfigFile, error) {
-	f, err := os.Open(path)
-	if err != nil {
-		return nil, err
+// daemonConfig holds the configuration state as a singleton.
+// It is initialised by the ParseFlagsAndConfig func and exposed through the Config function.
+var daemonConfig *ConfigFile
+
+// Config returns the config that was loaded while starting the daemon.
+// Panics when ParseFlagsAndConfig was not called earlier.
+func Config() *ConfigFile {
+	if daemonConfig == nil {
+		panic("ERROR: daemon.Config() called before daemon.ParseFlagsAndConfig()")
 	}
-	defer func() { _ = f.Close() }()
 
-	var c ConfigFile
+	return daemonConfig
+}
 
-	if err := defaults.Set(&c); err != nil {
-		return nil, err
-	}
+// ParseFlagsAndConfig parses the CLI flags provided to the executable and tries to load the config from the YAML file.
+// Prints any error during parsing or config loading to os.Stderr and exits.
+func ParseFlagsAndConfig() {
+	flags := Flags{Config: internal.SysConfDir + "/icinga-notifications/config.yml"}
+	if err := config.ParseFlags(&flags); err != nil {
+		if errors.Is(err, config.ErrInvalidArgument) {
+			panic(err)
+		}
 
-	d := yaml.NewDecoder(f)
-	if err := d.Decode(&c); err != nil {
-		return nil, err
+		utils.PrintErrorThenExit(err, ExitFailure)
 	}
 
-	if err := c.Validate(); err != nil {
-		return nil, err
+	if flags.Version {
+		internal.Version.Print("Icinga Notifications")
+		os.Exit(ExitSuccess)
 	}
 
-	return &c, nil
-}
+	daemonConfig = new(ConfigFile)
+	if err := config.FromYAMLFile(flags.Config, daemonConfig); err != nil {
+		if errors.Is(err, config.ErrInvalidArgument) {
+			panic(err)
+		}
 
-func (c *ConfigFile) Validate() error {
-	if err := c.Database.Validate(); err != nil {
-		return err
+		utils.PrintErrorThenExit(err, ExitFailure)
 	}
-	if err := c.Logging.Validate(); err != nil {
-		return err
-	}
-
-	return nil
 }