copy,copyto,move,moveto: implement logger flags to store result of sync

This enables the logger flags (`--combined`, `--missing-on-src`
etc.) for the `rclone copy` and `move` commands (as well as their
`copyto` and `moveto` variants) akin to `rclone sync`. Warnings for
unsupported/wonky flag combinations are also printed, e.g. when the
destination is not traversed but `--dest-after` is specified.

- fs/operations: add reusable methods for operation logging
- cmd/sync: use reusable methods for implementing logging in sync command
- cmd: implement logging for copy/copyto/move/moveto commands
- fs/operations/operationsflags: warn about logs in conjunction with --no-traverse
- cmd: add logger docs to copy and move commands

Fixes #8115

fs/operations/operationsflags/operationsflags.go

@@ -3,12 +3,28 @@
 package operationsflags
 
 import (
+	"context"
+	_ "embed"
+	"io"
+	"os"
+	"strings"
+
+	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config/flags"
 	"github.com/rclone/rclone/fs/hash"
 	"github.com/rclone/rclone/fs/operations"
+	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 )
 
+//go:embed operationsflags.md
+var help string
+
+// Help returns the help string cleaned up to simplify appending
+func Help() string {
+	return strings.TrimSpace(help) + "\n\n"
+}
+
 // AddLoggerFlagsOptions contains options for the Logger Flags
 type AddLoggerFlagsOptions struct {
 	Combined     string // a file with file names with leading sigils
@@ -20,6 +36,20 @@ type AddLoggerFlagsOptions struct {
 	DestAfter    string // files that exist on the destination post-sync
 }
 
+// AnySet checks if any of the logger flags have a non-blank value
+func (o AddLoggerFlagsOptions) AnySet() bool {
+	return anyNotBlank(o.Combined, o.MissingOnSrc, o.MissingOnDst, o.Match, o.Differ, o.ErrFile, o.DestAfter)
+}
+
+func anyNotBlank(s ...string) bool {
+	for _, x := range s {
+		if x != "" {
+			return true
+		}
+	}
+	return false
+}
+
 // AddLoggerFlags adds the logger flags to the cmdFlags command
 func AddLoggerFlags(cmdFlags *pflag.FlagSet, opt *operations.LoggerOpt, flagsOpt *AddLoggerFlagsOptions) {
 	flags.StringVarP(cmdFlags, &flagsOpt.Combined, "combined", "", flagsOpt.Combined, "Make a combined report of changes to this file", "Sync")
@@ -43,3 +73,75 @@ func AddLoggerFlags(cmdFlags *pflag.FlagSet, opt *operations.LoggerOpt, flagsOpt
 	flags.BoolVarP(cmdFlags, &opt.Absolute, "absolute", "", false, "Put a leading / in front of path names", "Sync")
 	// flags.BoolVarP(cmdFlags, &recurse, "recursive", "R", false, "Recurse into the listing", "")
 }
+
+// ConfigureLoggers verifies and sets up writers for log files requested via CLI flags
+func ConfigureLoggers(ctx context.Context, fdst fs.Fs, command *cobra.Command, opt *operations.LoggerOpt, flagsOpt AddLoggerFlagsOptions) (func(), error) {
+	closers := []io.Closer{}
+
+	if opt.TimeFormat == "max" {
+		opt.TimeFormat = operations.FormatForLSFPrecision(fdst.Precision())
+	}
+	opt.SetListFormat(ctx, command.Flags())
+	opt.NewListJSON(ctx, fdst, "")
+
+	open := func(name string, pout *io.Writer) error {
+		if name == "" {
+			return nil
+		}
+		if name == "-" {
+			*pout = os.Stdout
+			return nil
+		}
+		out, err := os.Create(name)
+		if err != nil {
+			return err
+		}
+		*pout = out
+		closers = append(closers, out)
+		return nil
+	}
+
+	if err := open(flagsOpt.Combined, &opt.Combined); err != nil {
+		return nil, err
+	}
+	if err := open(flagsOpt.MissingOnSrc, &opt.MissingOnSrc); err != nil {
+		return nil, err
+	}
+	if err := open(flagsOpt.MissingOnDst, &opt.MissingOnDst); err != nil {
+		return nil, err
+	}
+	if err := open(flagsOpt.Match, &opt.Match); err != nil {
+		return nil, err
+	}
+	if err := open(flagsOpt.Differ, &opt.Differ); err != nil {
+		return nil, err
+	}
+	if err := open(flagsOpt.ErrFile, &opt.Error); err != nil {
+		return nil, err
+	}
+	if err := open(flagsOpt.DestAfter, &opt.DestAfter); err != nil {
+		return nil, err
+	}
+
+	close := func() {
+		for _, closer := range closers {
+			err := closer.Close()
+			if err != nil {
+				fs.Errorf(nil, "Failed to close report output: %v", err)
+			}
+		}
+	}
+
+	ci := fs.GetConfig(ctx)
+	if ci.NoTraverse && opt.Combined != nil {
+		fs.LogPrintf(fs.LogLevelWarning, nil, "--no-traverse does not list any deletes (-) in --combined output\n")
+	}
+	if ci.NoTraverse && opt.MissingOnSrc != nil {
+		fs.LogPrintf(fs.LogLevelWarning, nil, "--no-traverse makes --missing-on-src produce empty output\n")
+	}
+	if ci.NoTraverse && opt.DestAfter != nil {
+		fs.LogPrintf(fs.LogLevelWarning, nil, "--no-traverse makes --dest-after produce incomplete output\n")
+	}
+
+	return close, nil
+}