[#532] cli: Respect XDG base directory spec

XDG base directory specification defines where various files
should be looked by an application. Hopefully, this makes `frostfs-cli`
more predictable and pleasant to work with. Luckily for us, golang already
has everything we need in the stdlib. This commit also gets rid of
`github.com/mitchellh/go-homedir` dependency.

Close #532
Refs #1455

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

cmd/frostfs-cli/modules/root.go

@@ -21,7 +21,6 @@ import (
 	"git.frostfs.info/TrueCloudLab/frostfs-node/misc"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/config"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/gendoc"
-	"github.com/mitchellh/go-homedir"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 )
@@ -112,13 +111,13 @@ func initConfig() {
 		// Use config file from the flag.
 		viper.SetConfigFile(cfgFile)
 	} else {
-		// Find home directory.
-		home, err := homedir.Dir()
+		// Find config directory.
+		configDir, err := os.UserConfigDir()
 		if err != nil {
-			common.PrintVerbose(rootCmd, "Get homedir: %s", err)
+			common.PrintVerbose(rootCmd, "Get config dir: %s", err)
 		} else {
-			// Search config in `$HOME/.config/frostfs-cli/` with name "config.yaml"
-			viper.AddConfigPath(filepath.Join(home, ".config", "frostfs-cli"))
+			// Search config in `$XDG_CONFIG_HOME/frostfs-cli/` with name "config.yaml"
+			viper.AddConfigPath(filepath.Join(configDir, "frostfs-cli"))
 			viper.SetConfigName("config")
 			viper.SetConfigType("yaml")
 		}

go.mod

@@ -27,7 +27,6 @@ require (
 	github.com/hashicorp/golang-lru/v2 v2.0.7
 	github.com/klauspost/compress v1.17.4
 	github.com/mailru/easyjson v0.7.7
-	github.com/mitchellh/go-homedir v1.1.0
 	github.com/mr-tron/base58 v1.2.0
 	github.com/multiformats/go-multiaddr v0.12.1
 	github.com/nspcc-dev/neo-go v0.106.3