feat: add configuration via config file

Uses a configuration file to change settings in CertGuard

Issue: #79

Author: pimg

README.md

@@ -18,10 +18,13 @@ With CertGuard it is currently possible to:
 ![demo](docs/demo.gif)
 
 ## File locations
-CertGuard uses two file locations:
+CertGuard uses following default file locations:
 - `~/.cache/certguard` location of the database/storage file
 - `~/.cache/certguard/import` import directory for importing CRLs from file
 - `~/.local/share/certguard` for the `debug.log` file
+- `~/.config/certguard` for the `config.yaml` file
+
+All these locations can be changed in the [config](#configuration) file.
 
 ## Themes
 CertGuard has predefined themes that can be switched using the `--theme` argument. Currently supported themes are:
@@ -55,6 +58,17 @@ All information on CRL's and revoked certificates are stored on a local SQLite d
 The Database schema used for Certguard only stores public information:
 ![database schema](docs/db_schema.svg)
 
+## Configuration
+CertGuard can be configured using one of three ways:
+1. command line flags
+2. environment variables
+3. config file
+
+The precedence is `command line flags` > `environment variables` > `config file` > `defaults`
+
+A sample config file is included in the repo: `config.yaml`
+The default locations CertGuard looks for the config file are the current directory (`.`) and `$HOME/.config/certguard`
+
 ## Development
 A MAKE file has been included for convenience:
 - `make run` builds and run the `certguard` application in `debug` mode

cmd/root.go

@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 
 	tea "github.com/charmbracelet/bubbletea"
+	"github.com/pimg/certguard/config"
 	"github.com/pimg/certguard/internal/adapter/db"
 	"github.com/pimg/certguard/internal/ports/models"
 	cmds "github.com/pimg/certguard/internal/ports/models/commands"
@@ -17,31 +18,39 @@ import (
 	"github.com/spf13/cobra"
 )
 
+var v *config.ViperConfig
+
 func init() {
-	rootCmd.PersistentFlags().Bool("debug", false, "enables debug logging to a file located in ~/.local/certguard/debug.log")
-	rootCmd.PersistentFlags().String("theme", "dracula", "set the theme of the application. Allowed values: 'dracula', 'gruvbox'")
+	v = config.NewViperConfig()
+	rootCmd.PersistentFlags().BoolVarP(&v.Config().Log.Debug, "debug", "d", false, "enables debug logging to a file located in ~/.local/certguard/debug.log")
+	rootCmd.PersistentFlags().StringVarP(&v.Config().Theme.Name, "theme", "t", "dracula", "set the theme of the application. Allowed values: 'dracula', 'gruvbox'")
+
+	// bind Cobra flags to viper config
+	_ = v.BindPFlag("config.theme.name", rootCmd.PersistentFlags().Lookup("theme"))
+	_ = v.BindPFlag("config.log.debug", rootCmd.PersistentFlags().Lookup("debug"))
 }
 
 var rootCmd = &cobra.Command{
 	Version: "v0.0.1",
 	Use:     "certguard",
 	Long:    "Certguard can download, store and inspect x.509 Certificate Revocation Lists",
 	Example: "certguard",
-	RunE:    runInteractiveCertGuard,
+	PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
+		return v.InitializeConfig()
+	},
+	RunE: runInteractiveCertGuard,
 }
 
 func runInteractiveCertGuard(cmd *cobra.Command, args []string) error {
-	debug, _ := cmd.Flags().GetBool("debug")
-	theme, _ := cmd.Flags().GetString("theme")
+	debug := v.Config().Log.Debug
+	theme := v.Config().Theme.Name
 
 	if debug {
-		homeDir, err := os.UserHomeDir()
+		logDir, err := logDir()
 		if err != nil {
-			fmt.Println("fatal:", err)
-			os.Exit(1)
+			return err
 		}
 
-		logDir := filepath.Join(homeDir, ".local", "share", "certguard")
 		err = os.MkdirAll(logDir, 0o777)
 		if err != nil {
 			return err
@@ -55,7 +64,12 @@ func runInteractiveCertGuard(cmd *cobra.Command, args []string) error {
 		defer f.Close()
 	}
 
-	cacheDir, err := determineCacheDir()
+	cacheDir, err := cacheDir()
+	if err != nil {
+		return err
+	}
+
+	importDir, err := importDir()
 	if err != nil {
 		return err
 	}
@@ -86,7 +100,7 @@ func runInteractiveCertGuard(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
-	storage, err := crl.NewStorage(libsqlStorage, cacheDir)
+	storage, err := crl.NewStorage(libsqlStorage, cacheDir, importDir)
 	if err != nil {
 		return err
 	}
@@ -107,7 +121,41 @@ func Execute() error {
 	return rootCmd.Execute()
 }
 
-func determineCacheDir() (string, error) {
+func cacheDir() (string, error) {
+	if v.Config().CacheDirectory != "" {
+		return v.Config().CacheDirectory, nil
+	}
+
+	return defaultDir()
+}
+
+func importDir() (string, error) {
+	if v.Config().ImportDirectory != "" {
+		return v.Config().ImportDirectory, nil
+	}
+
+	dir, err := defaultDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "import"), nil
+}
+
+func logDir() (string, error) {
+	if v.Config().Log.Directory != "" {
+		return v.Config().Log.Directory, nil
+	}
+
+	homeDir, err := os.UserHomeDir()
+	if err != nil {
+		return "", errors.New("could not create file path to User home dir, logging will not be enabled")
+	}
+
+	return filepath.Join(homeDir, ".local", "share", "certguard"), nil
+}
+
+func defaultDir() (string, error) {
 	homeDir, err := os.UserHomeDir()
 	if err != nil {
 		return "", errors.New("could not create file path to User home dir, Cache will not be enabled")

config.yaml

@@ -0,0 +1,5 @@
+config:
+  theme:
+    name: gruvbox
+  log:
+    debug: true

config/config.go

@@ -0,0 +1,21 @@
+package config
+
+type Config struct {
+	CacheDirectory  string
+	ImportDirectory string
+	Log             Log
+	Theme           Theme
+}
+
+type Log struct {
+	Debug     bool
+	Directory string
+}
+
+type Theme struct {
+	Name string
+}
+
+func New() *Config {
+	return &Config{}
+}

config/file.go

@@ -0,0 +1,67 @@
+package config
+
+import (
+	"strings"
+
+	"github.com/spf13/viper"
+)
+
+const (
+	configFileName = "config"
+	envPrefix      = "CG"
+)
+
+type ViperConfig struct {
+	*viper.Viper
+	cfg *Config
+}
+
+func NewViperConfig() *ViperConfig {
+	return &ViperConfig{viper.New(), New()}
+}
+
+func (v *ViperConfig) Config() *Config {
+	return v.cfg
+}
+
+func (v *ViperConfig) InitializeConfig() error {
+	// Set the base name of the config file, without the file extension.
+	v.SetConfigName(configFileName)
+	v.SetConfigType("yaml")
+
+	// Set as many paths as you like where viper should look for the
+	// config file. We are only looking in the current working directory.
+	v.AddConfigPath(".")
+	v.AddConfigPath("$HOME/.config/certguard")
+
+	// Attempt to read the config file, gracefully ignoring errors
+	// caused by a config file not being found. Return an error
+	// if we cannot parse the config file.
+	if err := v.ReadInConfig(); err != nil {
+		// It's okay if there isn't a config file
+		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
+			return err
+		}
+	}
+
+	// When we bind flags to environment variables expect that the
+	// environment variables are prefixed, e.g. a flag like --number
+	// binds to an environment variable STING_NUMBER. This helps
+	// avoid conflicts.
+	v.SetEnvPrefix(envPrefix)
+
+	// Environment variables can't have dashes in them, so bind them to their equivalent
+	// keys with underscores, e.g. --favorite-color to STING_FAVORITE_COLOR
+	v.SetEnvKeyReplacer(strings.NewReplacer("-", "_"))
+
+	// Bind to environment variables
+	// Works great for simple config names, but needs help for names
+	// like --favorite-color which we fix in the setFlags function
+	v.AutomaticEnv()
+
+	v.cfg.Theme.Name = v.GetString("config.theme.name")
+	v.cfg.Log.Debug = v.GetBool("config.log.debug")
+	v.cfg.Log.Directory = v.GetString("config.log.file")
+
+	return nil
+}

go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/charmbracelet/lipgloss v1.0.0
 	github.com/rubenv/sql-migrate v1.7.1
 	github.com/spf13/cobra v1.8.1
+	github.com/spf13/viper v1.19.0
 	github.com/stretchr/testify v1.10.0
 	github.com/tursodatabase/go-libsql v0.0.0-20241113154718-293fe7f21b08
 	golang.org/x/crypto v0.32.0
@@ -19,26 +20,40 @@ require (
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
 	github.com/charmbracelet/x/ansi v0.4.5 // indirect
 	github.com/charmbracelet/x/term v0.2.1 // indirect
-	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect
+	github.com/fsnotify/fsnotify v1.7.0 // indirect
 	github.com/go-gorp/gorp/v3 v3.1.0 // indirect
+	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/libsql/sqlite-antlr4-parser v0.0.0-20240721121621-c0bdc870f11c // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/magiconair/properties v1.8.7 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mattn/go-localereader v0.0.1 // indirect
 	github.com/mattn/go-runewidth v0.0.16 // indirect
+	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/muesli/ansi v0.0.0-20230316100256-276c6243b2f6 // indirect
 	github.com/muesli/cancelreader v0.2.2 // indirect
 	github.com/muesli/termenv v0.15.2 // indirect
-	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/pelletier/go-toml/v2 v2.2.2 // indirect
+	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
+	github.com/sagikazarmark/locafero v0.4.0 // indirect
+	github.com/sagikazarmark/slog-shim v0.1.0 // indirect
 	github.com/sahilm/fuzzy v0.1.1 // indirect
+	github.com/sourcegraph/conc v0.3.0 // indirect
+	github.com/spf13/afero v1.11.0 // indirect
+	github.com/spf13/cast v1.6.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/subosito/gotenv v1.6.0 // indirect
+	go.uber.org/atomic v1.9.0 // indirect
+	go.uber.org/multierr v1.9.0 // indirect
 	golang.org/x/exp v0.0.0-20241204233417-43b7b7cde48d // indirect
 	golang.org/x/sync v0.10.0 // indirect
 	golang.org/x/sys v0.29.0 // indirect
 	golang.org/x/text v0.21.0 // indirect
+	gopkg.in/ini.v1 v1.67.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )