listremotes: added options for filtering, ordering and json output

cmd/listremotes/listremotes.go

@@ -2,60 +2,236 @@
 package ls
 
 import (
+	"encoding/json"
 	"fmt"
+	"os"
+	"regexp"
 	"sort"
+	"strings"
 
 	"github.com/rclone/rclone/cmd"
+	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config"
 	"github.com/rclone/rclone/fs/config/flags"
+	"github.com/rclone/rclone/fs/filter"
 	"github.com/spf13/cobra"
 )
 
-// Globals
 var (
 	listLong          bool
+	jsonOutput        bool
+	filterName        string
+	filterType        string
+	filterSource      string
+	filterDescription string
+	orderBy           string
 )
 
 func init() {
 	cmd.Root.AddCommand(commandDefinition)
 	cmdFlags := commandDefinition.Flags()
-	flags.BoolVarP(cmdFlags, &listLong, "long", "", listLong, "Show the type and the description as well as names", "")
+	flags.BoolVarP(cmdFlags, &listLong, "long", "", false, "Show type, source and description in addition to name", "")
+	flags.StringVarP(cmdFlags, &filterName, "name", "", "", "Filter remotes by name", "")
+	flags.StringVarP(cmdFlags, &filterType, "type", "", "", "Filter remotes by type", "")
+	flags.StringVarP(cmdFlags, &filterSource, "source", "", "", "filter remotes by source", "")
+	flags.StringVarP(cmdFlags, &filterDescription, "description", "", "", "filter remotes by description", "")
+	flags.StringVarP(cmdFlags, &orderBy, "order-by", "", "", "Instructions on how to order the result, e.g. 'type,name=descending'", "")
+	flags.BoolVarP(cmdFlags, &jsonOutput, "json", "", false, "Format output as JSON", "")
+}
+
+// lessFn compares to remotes for order by
+type lessFn func(a, b config.Remote) bool
+
+// newLess returns a function for comparing remotes based on an order by string
+func newLess(orderBy string) (less lessFn, err error) {
+	if orderBy == "" {
+		return nil, nil
+	}
+	parts := strings.Split(strings.ToLower(orderBy), ",")
+	n := len(parts)
+	for i := n - 1; i >= 0; i-- {
+		fieldAndDirection := strings.SplitN(parts[i], "=", 2)
+
+		descending := false
+		if len(fieldAndDirection) > 1 {
+			switch fieldAndDirection[1] {
+			case "ascending", "asc":
+			case "descending", "desc":
+				descending = true
+			default:
+				return nil, fmt.Errorf("unknown --order-by direction %q", fieldAndDirection[1])
+			}
+		}
+
+		var field func(o config.Remote) string
+		switch fieldAndDirection[0] {
+		case "name":
+			field = func(o config.Remote) string {
+				return o.Name
+			}
+		case "type":
+			field = func(o config.Remote) string {
+				return o.Type
+			}
+		case "source":
+			field = func(o config.Remote) string {
+				return o.Source
+			}
+		case "description":
+			field = func(o config.Remote) string {
+				return o.Description
+			}
+		default:
+			return nil, fmt.Errorf("unknown --order-by field %q", fieldAndDirection[0])
+		}
+
+		var thisLess lessFn
+		if descending {
+			thisLess = func(a, b config.Remote) bool {
+				return field(a) > field(b)
+			}
+		} else {
+			thisLess = func(a, b config.Remote) bool {
+				return field(a) < field(b)
+			}
+		}
+
+		if i == n-1 {
+			less = thisLess
+		} else {
+			nextLess := less
+			less = func(a, b config.Remote) bool {
+				if field(a) == field(b) {
+					return nextLess(a, b)
+				}
+				return thisLess(a, b)
+			}
+		}
+	}
+	return less, nil
 }
 
 var commandDefinition = &cobra.Command{
-	Use:   "listremotes",
+	Use:   "listremotes [<filter>]",
 	Short: `List all the remotes in the config file and defined in environment variables.`,
 	Long: `
-rclone listremotes lists all the available remotes from the config file.
+rclone listremotes lists all the available remotes from the config file,
+or the remotes matching an optional filter.
 
-When used with the ` + "`--long`" + ` flag it lists the types and the descriptions too.
+Prints the result in human-readable format by default, and as a simple list of
+remote names, or if used with flag ` + "`--long`" + ` a tabular format including
+all attributes of the remotes: name, type, source and description. Using flag
+` + "`--json`" + ` produces machine-readable output instead, which always includes
+all attributes.
+
+Result can be filtered by a filter argument which applies to all attributes,
+and/or filter flags specific for each attribute. The values must be specified
+according to regular rclone filtering pattern syntax.
 `,
 	Annotations: map[string]string{
 		"versionIntroduced": "v1.34",
 	},
-	Run: func(command *cobra.Command, args []string) {
-		cmd.CheckArgs(0, 0, command, args)
-		remotes := config.FileSections()
-		sort.Strings(remotes)
-		maxlen := 1
-		maxlentype := 1
+	RunE: func(command *cobra.Command, args []string) error {
+		cmd.CheckArgs(0, 1, command, args)
+		var filterDefault string
+		if len(args) > 0 {
+			filterDefault = args[0]
+		}
+		filters := make(map[string]*regexp.Regexp)
+		for k, v := range map[string]string{
+			"all":         filterDefault,
+			"name":        filterName,
+			"type":        filterType,
+			"source":      filterSource,
+			"description": filterDescription,
+		} {
+			if v != "" {
+				filterRe, err := filter.GlobStringToRegexp(v, false)
+				if err != nil {
+					return fmt.Errorf("invalid %s filter argument: %w", k, err)
+				}
+				fs.Debugf(nil, "Filter for %s: %s", k, filterRe.String())
+				filters[k] = filterRe
+			}
+		}
+		remotes := config.GetRemotes()
+		maxName := 0
+		maxType := 0
+		maxSource := 0
+		i := 0
 		for _, remote := range remotes {
-			if len(remote) > maxlen {
-				maxlen = len(remote)
-			}
-			t := config.FileGet(remote, "type")
-			if len(t) > maxlentype {
-				maxlentype = len(t)
+			include := true
+			for k, v := range filters {
+				if k == "all" && !(v.MatchString(remote.Name) || v.MatchString(remote.Type) || v.MatchString(remote.Source) || v.MatchString(remote.Description)) {
+					include = false
+				} else if k == "name" && !v.MatchString(remote.Name) {
+					include = false
+				} else if k == "type" && !v.MatchString(remote.Type) {
+					include = false
+				} else if k == "source" && !v.MatchString(remote.Source) {
+					include = false
+				} else if k == "description" && !v.MatchString(remote.Description) {
+					include = false
 				}
 			}
+			if include {
+				if len(remote.Name) > maxName {
+					maxName = len(remote.Name)
+				}
+				if len(remote.Type) > maxType {
+					maxType = len(remote.Type)
+				}
+				if len(remote.Source) > maxSource {
+					maxSource = len(remote.Source)
+				}
+				remotes[i] = remote
+				i++
+			}
+		}
+		remotes = remotes[:i]
+
+		less, err := newLess(orderBy)
+		if err != nil {
+			return err
+		}
+		if less != nil {
+			sliceLessFn := func(i, j int) bool {
+				return less(remotes[i], remotes[j])
+			}
+			sort.SliceStable(remotes, sliceLessFn)
+		}
+
+		if jsonOutput {
+			fmt.Println("[")
+			first := true
 			for _, remote := range remotes {
-			if listLong {
-				remoteType := config.FileGet(remote, "type")
-				description := config.FileGet(remote, "description")
-				fmt.Printf("%-*s %-*s %s\n", maxlen+1, remote+":", maxlentype+1, remoteType, description)
+				out, err := json.Marshal(remote)
+				if err != nil {
+					return fmt.Errorf("failed to marshal remote object: %w", err)
+				}
+				if first {
+					first = false
 				} else {
-				fmt.Printf("%s:\n", remote)
+					fmt.Print(",\n")
+				}
+				_, err = os.Stdout.Write(out)
+				if err != nil {
+					return fmt.Errorf("failed to write to output: %w", err)
 				}
 			}
+			if !first {
+				fmt.Println()
+			}
+			fmt.Println("]")
+		} else if listLong {
+			for _, remote := range remotes {
+				fmt.Printf("%-*s %-*s %-*s %s\n", maxName+1, remote.Name+":", maxType, remote.Type, maxSource, remote.Source, remote.Description)
+			}
+		} else {
+			for _, remote := range remotes {
+				fmt.Printf("%s:\n", remote.Name)
+			}
+		}
+		return nil
 	},
 }

fs/config/config.go

@@ -444,11 +444,12 @@ func SetValueAndSave(remote, key, value string) error {
 	return nil
 }
 
-// Remote defines a remote with a name, type and source
+// Remote defines a remote with a name, type, source and description
 type Remote struct {
 	Name        string `json:"name"`
 	Type        string `json:"type"`
 	Source      string `json:"source"`
+	Description string `json:"description"`
 }
 
 var remoteEnvRe = regexp.MustCompile(`^RCLONE_CONFIG_(.+?)_TYPE=(.+)$`)
@@ -482,10 +483,12 @@ func GetRemotes() []Remote {
 		if !remoteExists(section) {
 			typeValue, found := LoadedData().GetValue(section, "type")
 			if found {
+				description, _ := LoadedData().GetValue(section, "description")
 				remotes = append(remotes, Remote{
 					Name:        section,
 					Type:        typeValue,
 					Source:      "file",
+					Description: description,
 				})
 			}
 		}