Change storage paths to follow OS conventions; migrate folder (#2955)

cmd/main.go

@@ -22,12 +22,15 @@ import (
 	"io/ioutil"
 	"net"
 	"os"
+	"path/filepath"
+	"runtime"
 	"strconv"
 	"strings"
 	"time"
 
 	"github.com/caddyserver/caddy/v2"
 	"github.com/caddyserver/caddy/v2/caddyconfig"
+	"go.uber.org/zap"
 )
 
 // Main implements the main function of the caddy command.
@@ -226,3 +229,71 @@ func printEnvironment() {
 		fmt.Println(v)
 	}
 }
+
+// moveStorage moves the old default dataDir to the new default dataDir.
+// TODO: This is TEMPORARY until the release candidates.
+func moveStorage() {
+	// get the home directory (the old way)
+	oldHome := os.Getenv("HOME")
+	if oldHome == "" && runtime.GOOS == "windows" {
+		drive := os.Getenv("HOMEDRIVE")
+		path := os.Getenv("HOMEPATH")
+		oldHome = drive + path
+		if drive == "" || path == "" {
+			oldHome = os.Getenv("USERPROFILE")
+		}
+	}
+	if oldHome == "" {
+		oldHome = "."
+	}
+	oldDataDir := filepath.Join(oldHome, ".local", "share", "caddy")
+
+	// nothing to do if old data dir doesn't exist
+	_, err := os.Stat(oldDataDir)
+	if os.IsNotExist(err) {
+		return
+	}
+
+	// nothing to do if the new data dir is the same as the old one
+	newDataDir := caddy.AppDataDir()
+	if oldDataDir == newDataDir {
+		return
+	}
+
+	logger := caddy.Log().Named("automigrate").With(
+		zap.String("old_dir", oldDataDir),
+		zap.String("new_dir", newDataDir))
+
+	logger.Info("beginning one-time data directory migration",
+		zap.String("details", "https://github.com/caddyserver/caddy/issues/2955"))
+
+	// if new data directory exists, avoid auto-migration as a conservative safety measure
+	_, err = os.Stat(newDataDir)
+	if !os.IsNotExist(err) {
+		logger.Error("new data directory already exists; skipping auto-migration as conservative safety measure",
+			zap.Error(err),
+			zap.String("instructions", "https://github.com/caddyserver/caddy/issues/2955#issuecomment-570000333"))
+		return
+	}
+
+	// construct the new data directory's parent folder
+	err = os.MkdirAll(filepath.Dir(newDataDir), 0700)
+	if err != nil {
+		logger.Error("unable to make new datadirectory - follow link for instructions",
+			zap.String("instructions", "https://github.com/caddyserver/caddy/issues/2955#issuecomment-570000333"),
+			zap.Error(err))
+		return
+	}
+
+	// folder structure is same, so just try to rename (move) it;
+	// this fails if the new path is on a separate device
+	err = os.Rename(oldDataDir, newDataDir)
+	if err != nil {
+		logger.Error("new data directory already exists; skipping auto-migration as conservative safety measure - follow link for instructions",
+			zap.String("instructions", "https://github.com/caddyserver/caddy/issues/2955#issuecomment-570000333"),
+			zap.Error(err))
+	}
+
+	logger.Info("successfully completed one-time migration of data directory",
+		zap.String("details", "https://github.com/caddyserver/caddy/issues/2955"))
+}