config: make temporary directory user-configurable

See #5591

fs/config/configflags/configflags.go

@@ -6,6 +6,7 @@ package configflags
 import (
 	"log"
 	"net"
+	"os"
 	"strconv"
 	"strings"
 
@@ -23,6 +24,7 @@ var (
 	verbose         int
 	quiet           bool
 	configPath      string
+	tempDir         string
 	dumpHeaders     bool
 	dumpBodies      bool
 	deleteBefore    bool
@@ -47,6 +49,7 @@ func AddFlags(ci *fs.ConfigInfo, flagSet *pflag.FlagSet) {
 	flags.IntVarP(flagSet, &ci.Transfers, "transfers", "", ci.Transfers, "Number of file transfers to run in parallel.")
 	flags.StringVarP(flagSet, &configPath, "config", "", config.GetConfigPath(), "Config file.")
 	flags.StringVarP(flagSet, &config.CacheDir, "cache-dir", "", config.CacheDir, "Directory rclone will use for caching.")
+	flags.StringVarP(flagSet, &tempDir, "temp-dir", "", os.TempDir(), "Directory rclone will use for temporary files.")
 	flags.BoolVarP(flagSet, &ci.CheckSum, "checksum", "c", ci.CheckSum, "Skip based on checksum (if available) & size, not mod-time & size")
 	flags.BoolVarP(flagSet, &ci.SizeOnly, "size-only", "", ci.SizeOnly, "Skip based on size only, not mod-time or checksum")
 	flags.BoolVarP(flagSet, &ci.IgnoreTimes, "ignore-times", "I", ci.IgnoreTimes, "Don't skip files that match size and time - transfer all files")
@@ -278,6 +281,11 @@ func SetFlags(ci *fs.ConfigInfo) {
 		log.Fatalf("--config: Failed to set %q as config path: %v", configPath, err)
 	}
 
+	// Set path to temp dir
+	if err := config.SetTempDir(tempDir); err != nil {
+		log.Fatalf("--temp-dir: Failed to set %q as temp dir: %v", tempDir, err)
+	}
+
 	// Set whether multi-thread-streams was set
 	multiThreadStreamsFlag := pflag.Lookup("multi-thread-streams")
 	ci.MultiThreadSet = multiThreadStreamsFlag != nil && multiThreadStreamsFlag.Changed