Add --json to many of the CLI commands

Add a --json flag to most of the CLI commands, to force output that
would have gone to stdout to be output as JSON instead of whatever form
it would otherwise take.  Error messages sent to stderr are still plain
text.

Use this chance to rework the wrapping logic so that it's more
consistent: commands that take multiple IDs attempt the specified
operation on all of them, and report errors afterward.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

cmd/oci-storage/container.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 
@@ -19,11 +20,19 @@ func container(flags *mflag.FlagSet, action string, m storage.Mall, args []strin
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 		return 1
 	}
+	matches := []storage.Container{}
 	for _, container := range containers {
 		for _, arg := range args {
 			if container.ID != arg && container.Name != "" && container.Name != arg {
 				continue
 			}
+			matches = append(matches, container)
+		}
+	}
+	if jsonOutput {
+		json.NewEncoder(os.Stdout).Encode(matches)
+	} else {
+		for _, container := range matches {
 			fmt.Printf("ID: %s\n", container.ID)
 			if container.Name != "" {
 				fmt.Printf("Name: %s\n", container.Name)
@@ -37,6 +46,9 @@ func container(flags *mflag.FlagSet, action string, m storage.Mall, args []strin
 			fmt.Printf("Layer: %s\n", container.LayerID)
 		}
 	}
+	if len(matches) != len(args) {
+		return 1
+	}
 	return 0
 }
 
@@ -47,5 +59,8 @@ func init() {
 		usage:       "Examine a container",
 		action:      container,
 		minArgs:     1,
+		addFlags: func(flags *mflag.FlagSet, cmd *command) {
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
+		},
 	})
 }

cmd/oci-storage/containers.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 
@@ -14,10 +15,14 @@ func containers(flags *mflag.FlagSet, action string, m storage.Mall, args []stri
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 		return 1
 	}
-	for _, container := range containers {
+	if jsonOutput {
-		fmt.Printf("%s\n", container.ID)
+		json.NewEncoder(os.Stdout).Encode(containers)
-		if container.Name != "" {
+	} else {
-			fmt.Printf("\t%s\n", container.Name)
+		for _, container := range containers {
+			fmt.Printf("%s\n", container.ID)
+			if container.Name != "" {
+				fmt.Printf("\t%s\n", container.Name)
+			}
 		}
 	}
 	return 0
@@ -30,5 +35,8 @@ func init() {
 		usage:       "List containers",
 		action:      containers,
 		maxArgs:     0,
+		addFlags: func(flags *mflag.FlagSet, cmd *command) {
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
+		},
 	})
 }

cmd/oci-storage/create.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -29,10 +30,14 @@ func createLayer(flags *mflag.FlagSet, action string, m storage.Mall, args []str
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 		return 1
 	}
-	if layer.Name != "" {
+	if jsonOutput {
-		fmt.Printf("%s\t%s\n", layer.ID, layer.Name)
+		json.NewEncoder(os.Stdout).Encode(layer)
 	} else {
-		fmt.Printf("%s\n", layer.ID)
+		if layer.Name != "" {
+			fmt.Printf("%s\t%s\n", layer.ID, layer.Name)
+		} else {
+			fmt.Printf("%s\n", layer.ID)
+		}
 	}
 	return 0
 }
@@ -56,10 +61,14 @@ func createImage(flags *mflag.FlagSet, action string, m storage.Mall, args []str
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 		return 1
 	}
-	if image.Name != "" {
+	if jsonOutput {
-		fmt.Printf("%s\t%s\n", image.ID, image.Name)
+		json.NewEncoder(os.Stdout).Encode(image)
 	} else {
-		fmt.Printf("%s\n", image.ID)
+		if image.Name != "" {
+			fmt.Printf("%s\t%s\n", image.ID, image.Name)
+		} else {
+			fmt.Printf("%s\n", image.ID)
+		}
 	}
 	return 0
 }
@@ -83,10 +92,14 @@ func createContainer(flags *mflag.FlagSet, action string, m storage.Mall, args [
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 		return 1
 	}
-	if container.Name != "" {
+	if jsonOutput {
-		fmt.Printf("%s\t%s\n", container.ID, container.Name)
+		json.NewEncoder(os.Stdout).Encode(container)
 	} else {
-		fmt.Printf("%s\n", container.ID)
+		if container.Name != "" {
+			fmt.Printf("%s\t%s\n", container.ID, container.Name)
+		} else {
+			fmt.Printf("%s\n", container.ID)
+		}
 	}
 	return 0
 }
@@ -103,6 +116,7 @@ func init() {
 			flags.StringVar(&paramName, []string{"-name", "n"}, "", "Layer name")
 			flags.StringVar(&paramID, []string{"-id", "i"}, "", "Layer ID")
 			flags.BoolVar(&paramCreateRO, []string{"-readonly", "r"}, false, "Mark as read-only")
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
 		},
 	})
 	commands = append(commands, command{
@@ -117,6 +131,7 @@ func init() {
 			flags.StringVar(&paramID, []string{"-id", "i"}, "", "Image ID")
 			flags.StringVar(&paramMetadata, []string{"-metadata", "m"}, "", "Metadata")
 			flags.StringVar(&paramMetadataFile, []string{"-metadata-file", "f"}, "", "Metadata File")
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
 		},
 	})
 	commands = append(commands, command{
@@ -131,6 +146,7 @@ func init() {
 			flags.StringVar(&paramID, []string{"-id", "i"}, "", "Container ID")
 			flags.StringVar(&paramMetadata, []string{"-metadata", "m"}, "", "Metadata")
 			flags.StringVar(&paramMetadataFile, []string{"-metadata-file", "f"}, "", "Metadata File")
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
 		},
 	})
 }

cmd/oci-storage/delete.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 
@@ -12,10 +13,22 @@ func deleteThing(flags *mflag.FlagSet, action string, m storage.Mall, args []str
 	if len(args) < 1 {
 		return 1
 	}
+	deleted := make(map[string]error)
 	for _, what := range args {
 		err := m.Delete(what)
+		deleted[what] = err
+	}
+	if jsonOutput {
+		json.NewEncoder(os.Stdout).Encode(deleted)
+	} else {
+		for what, err := range deleted {
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "%s: %v\n", what, err)
+			}
+		}
+	}
+	for _, err := range deleted {
 		if err != nil {
-			fmt.Fprintf(os.Stderr, "%s: %v\n", what, err)
 			return 1
 		}
 	}
@@ -29,5 +42,8 @@ func init() {
 		usage:       "Delete a layer or image or container",
 		minArgs:     1,
 		action:      deleteThing,
+		addFlags: func(flags *mflag.FlagSet, cmd *command) {
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
+		},
 	})
 }

cmd/oci-storage/exists.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
+	"os"
 
 	"github.com/containers/storage/pkg/mflag"
 	"github.com/containers/storage/storage"
@@ -13,15 +15,25 @@ func exist(flags *mflag.FlagSet, action string, m storage.Mall, args []string) i
 	if len(args) < 1 {
 		return 1
 	}
-	allExist := true
+	anyMissing := false
+	existDict := make(map[string]bool)
 	for _, what := range args {
 		exists := m.Exists(what)
-		if !existQuiet {
+		existDict[what] = exists
-			fmt.Printf("%s: %v\n", what, exists)
+		if !exists {
+			anyMissing = true
 		}
-		allExist = allExist && exists
 	}
-	if !allExist {
+	if jsonOutput {
+		json.NewEncoder(os.Stdout).Encode(existDict)
+	} else {
+		if !existQuiet {
+			for what, exists := range existDict {
+				fmt.Printf("%s: %v\n", what, exists)
+			}
+		}
+	}
+	if anyMissing {
 		return 1
 	}
 	return 0
@@ -36,6 +48,7 @@ func init() {
 		action:      exist,
 		addFlags: func(flags *mflag.FlagSet, cmd *command) {
 			flags.BoolVar(&existQuiet, []string{"-quiet", "q"}, existQuiet, "Don't print names")
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
 		},
 	})
 }

cmd/oci-storage/image.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 
@@ -14,11 +15,19 @@ func image(flags *mflag.FlagSet, action string, m storage.Mall, args []string) i
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 		return 1
 	}
+	matched := []storage.Image{}
 	for _, image := range images {
 		for _, arg := range args {
 			if image.ID != arg && image.Name != "" && image.Name != arg {
 				continue
 			}
+			matched = append(matched, image)
+		}
+	}
+	if jsonOutput {
+		json.NewEncoder(os.Stdout).Encode(matched)
+	} else {
+		for _, image := range matched {
 			fmt.Printf("ID: %s\n", image.ID)
 			if image.Name != "" {
 				fmt.Printf("Name: %s\n", image.Name)
@@ -26,6 +35,9 @@ func image(flags *mflag.FlagSet, action string, m storage.Mall, args []string) i
 			fmt.Printf("Top Layer: %s\n", image.TopLayer)
 		}
 	}
+	if len(matched) != len(args) {
+		return 1
+	}
 	return 0
 }
 
@@ -36,5 +48,8 @@ func init() {
 		usage:       "Examine an image",
 		action:      image,
 		minArgs:     1,
+		addFlags: func(flags *mflag.FlagSet, cmd *command) {
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
+		},
 	})
 }

cmd/oci-storage/images.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 
@@ -14,10 +15,14 @@ func images(flags *mflag.FlagSet, action string, m storage.Mall, args []string)
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 		return 1
 	}
-	for _, image := range images {
+	if jsonOutput {
-		fmt.Printf("%s\n", image.ID)
+		json.NewEncoder(os.Stdout).Encode(images)
-		if image.Name != "" {
+	} else {
-			fmt.Printf("\t%s\n", image.Name)
+		for _, image := range images {
+			fmt.Printf("%s\n", image.ID)
+			if image.Name != "" {
+				fmt.Printf("\t%s\n", image.Name)
+			}
 		}
 	}
 	return 0
@@ -30,5 +35,8 @@ func init() {
 		usage:       "List images",
 		action:      images,
 		maxArgs:     0,
+		addFlags: func(flags *mflag.FlagSet, cmd *command) {
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
+		},
 	})
 }

cmd/oci-storage/layers.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 
@@ -16,6 +17,10 @@ func layers(flags *mflag.FlagSet, action string, m storage.Mall, args []string)
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 		return 1
 	}
+	if jsonOutput {
+		json.NewEncoder(os.Stdout).Encode(layers)
+		return 0
+	}
 	imageMap := make(map[string]storage.Image)
 	if images, err := m.Images(); err == nil {
 		for _, image := range images {
@@ -92,6 +97,7 @@ func init() {
 		maxArgs:     0,
 		addFlags: func(flags *mflag.FlagSet, cmd *command) {
 			flags.BoolVar(&listLayersTree, []string{"-tree", "t"}, listLayersTree, "Use a tree")
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
 		},
 	})
 }

cmd/oci-storage/main.go

@@ -22,7 +22,10 @@ type command struct {
 	action      func(*mflag.FlagSet, string, storage.Mall, []string) int
 }
 
-var commands = []command{}
+var (
+	commands   = []command{}
+	jsonOutput = false
+)
 
 func main() {
 	if reexec.Init() {
@@ -30,18 +33,24 @@ func main() {
 	}
 
 	graphRoot := "/var/lib/oci-storage"
-	graphDriver := os.Getenv("DOCKER_GRAPHDRIVER")
+	graphDriver := os.Getenv("STORAGE_DRIVER")
-	graphOptions := strings.Split(os.Getenv("DOCKER_STORAGE_OPTS"), ",")
+	if graphDriver == "" {
+		graphDriver = os.Getenv("DOCKER_GRAPHDRIVER")
+	}
+	graphOptions := strings.Split(os.Getenv("STORAGE_OPTS"), ",")
 	if len(graphOptions) == 1 && graphOptions[0] == "" {
-		graphOptions = nil
+		graphOptions = strings.Split(os.Getenv("DOCKER_STORAGE_OPTS"), ",")
+		if len(graphOptions) == 1 && graphOptions[0] == "" {
+			graphOptions = nil
+		}
 	}
 	debug := false
 
 	makeFlags := func(command string, eh mflag.ErrorHandling) *mflag.FlagSet {
 		flags := mflag.NewFlagSet(command, eh)
 		flags.StringVar(&graphRoot, []string{"-graph", "g"}, graphRoot, "Root of the storage tree")
-		flags.StringVar(&graphDriver, []string{"-storage-driver", "s"}, graphDriver, "Storage driver to use ($DOCKER_GRAPHDRIVER)")
+		flags.StringVar(&graphDriver, []string{"-storage-driver", "s"}, graphDriver, "Storage driver to use ($STORAGE_DRIVER)")
-		flags.Var(opts.NewListOptsRef(&graphOptions, nil), []string{"-storage-opt"}, "Set storage driver options ($DOCKER_STORAGE_OPTS)")
+		flags.Var(opts.NewListOptsRef(&graphOptions, nil), []string{"-storage-opt"}, "Set storage driver options ($STORAGE_OPTS)")
 		flags.BoolVar(&debug, []string{"-debug", "D"}, debug, "Print debugging information")
 		return flags
 	}

cmd/oci-storage/metadata.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -16,27 +17,29 @@ func metadata(flags *mflag.FlagSet, action string, m storage.Mall, args []string
 	if len(args) < 1 {
 		return 1
 	}
-	allExist := true
+	metadataDict := make(map[string]string)
+	missingAny := false
 	for _, what := range args {
-		exists := false
 		if container, err := m.GetContainer(what); err == nil {
-			exists = true
+			metadataDict[what] = strings.TrimSuffix(container.Metadata, "\n")
-			if metadataQuiet {
-				fmt.Printf("%s\n", strings.TrimSuffix(container.Metadata, "\n"))
-			} else {
-				fmt.Printf("%s: %s\n", what, strings.TrimSuffix(container.Metadata, "\n"))
-			}
 		} else if image, err := m.GetImage(what); err == nil {
-			exists = true
+			metadataDict[what] = strings.TrimSuffix(image.Metadata, "\n")
+		} else {
+			missingAny = true
+		}
+	}
+	if jsonOutput {
+		json.NewEncoder(os.Stdout).Encode(metadataDict)
+	} else {
+		for id, metadata := range metadataDict {
 			if metadataQuiet {
-				fmt.Printf("%s\n", strings.TrimSuffix(image.Metadata, "\n"))
+				fmt.Printf("%s\n", metadata)
 			} else {
-				fmt.Printf("%s: %s\n", what, strings.TrimSuffix(image.Metadata, "\n"))
+				fmt.Printf("%s: %s\n", id, metadata)
 			}
 		}
-		allExist = allExist && exists
 	}
-	if !allExist {
+	if missingAny {
 		return 1
 	}
 	return 0
@@ -78,7 +81,8 @@ func init() {
 		minArgs:     1,
 		action:      metadata,
 		addFlags: func(flags *mflag.FlagSet, cmd *command) {
-			flags.BoolVar(&metadataQuiet, []string{"-quiet", "q"}, metadataQuiet, "Don't print names and IDs")
+			flags.BoolVar(&metadataQuiet, []string{"-quiet", "q"}, metadataQuiet, "Omit names and IDs")
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
 		},
 	})
 	commands = append(commands, command{

cmd/oci-storage/mount.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 
@@ -8,24 +9,61 @@ import (
 	"github.com/containers/storage/storage"
 )
 
+type mountPointOrError struct {
+	ID         string `json:"id"`
+	MountPoint string `json:"mountpoint"`
+	Error      error  `json:"error"`
+}
+type mountPointError struct {
+	ID    string `json:"id"`
+	Error error  `json:"error"`
+}
+
 func mount(flags *mflag.FlagSet, action string, m storage.Mall, args []string) int {
+	moes := []mountPointOrError{}
 	for _, arg := range args {
 		result, err := m.Mount(arg, paramMountLabel)
-		if err != nil {
+		moes = append(moes, mountPointOrError{arg, result, err})
-			fmt.Fprintf(os.Stderr, "%s while mounting %s\n", err, arg)
+	}
+	if jsonOutput {
+		json.NewEncoder(os.Stdout).Encode(moes)
+	} else {
+		for _, mountOrError := range moes {
+			if mountOrError.Error != nil {
+				fmt.Fprintf(os.Stderr, "%s while mounting %s\n", mountOrError.Error, mountOrError.ID)
+			}
+			fmt.Printf("%s\n", mountOrError.MountPoint)
+		}
+	}
+	for _, mountOrErr := range moes {
+		if mountOrErr.Error != nil {
 			return 1
 		}
-		fmt.Printf("%s\n", result)
 	}
 	return 0
 }
 
 func unmount(flags *mflag.FlagSet, action string, m storage.Mall, args []string) int {
+	mes := []mountPointError{}
+	errors := false
 	for _, arg := range args {
-		if err := m.Unmount(arg); err != nil {
+		err := m.Unmount(arg)
-			fmt.Fprintf(os.Stderr, "%s while unmounting %s\n", err, arg)
+		if err != nil {
-			return 1
+			errors = true
 		}
+		mes = append(mes, mountPointError{arg, err})
+	}
+	if jsonOutput {
+		json.NewEncoder(os.Stdout).Encode(mes)
+	} else {
+		for _, me := range mes {
+			if me.Error != nil {
+				fmt.Fprintf(os.Stderr, "%s while unmounting %s\n", me.Error, me.ID)
+			}
+		}
+	}
+	if errors {
+		return 1
 	}
 	return 0
 }
@@ -39,6 +77,7 @@ func init() {
 		action:      mount,
 		addFlags: func(flags *mflag.FlagSet, cmd *command) {
 			flags.StringVar(&paramMountLabel, []string{"-label", "l"}, "", "Mount Label")
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
 		},
 	})
 	commands = append(commands, command{
@@ -47,5 +86,8 @@ func init() {
 		usage:       "Unmount a layer or container",
 		minArgs:     1,
 		action:      unmount,
+		addFlags: func(flags *mflag.FlagSet, cmd *command) {
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
+		},
 	})
 }

cmd/oci-storage/status.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 
@@ -14,8 +15,12 @@ func status(flags *mflag.FlagSet, action string, m storage.Mall, args []string)
 		fmt.Fprintf(os.Stderr, "status: %v\n", err)
 		return 1
 	}
-	for _, pair := range status {
+	if jsonOutput {
-		fmt.Fprintf(os.Stderr, "%s: %s\n", pair[0], pair[1])
+		json.NewEncoder(os.Stdout).Encode(status)
+	} else {
+		for _, pair := range status {
+			fmt.Fprintf(os.Stderr, "%s: %s\n", pair[0], pair[1])
+		}
 	}
 	return 0
 }
@@ -26,5 +31,8 @@ func init() {
 		usage:   "Check on graph driver status",
 		minArgs: 0,
 		action:  status,
+		addFlags: func(flags *mflag.FlagSet, cmd *command) {
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
+		},
 	})
 }

cmd/oci-storage/wipe.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 
@@ -10,8 +11,18 @@ import (
 
 func wipe(flags *mflag.FlagSet, action string, m storage.Mall, args []string) int {
 	err := m.Wipe()
+	if jsonOutput {
+		if err == nil {
+			json.NewEncoder(os.Stdout).Encode(string(""))
+		} else {
+			json.NewEncoder(os.Stdout).Encode(err)
+		}
+	} else {
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s: %v\n", action, err)
+		}
+	}
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "%s: %v\n", action, err)
 		return 1
 	}
 	return 0
@@ -23,5 +34,8 @@ func init() {
 		usage:   "Wipe all layers, images, and containers",
 		minArgs: 0,
 		action:  wipe,
+		addFlags: func(flags *mflag.FlagSet, cmd *command) {
+			flags.BoolVar(&jsonOutput, []string{"-json", "j"}, jsonOutput, "prefer JSON output")
+		},
 	})
 }