Add string/json output string mc pipe (#5065)

This commit adds a string message and json output to mc pipe.  The
implementation is heavily inspired by the one in mc cp, just adapted to
the different semantics of pipe.

cmd/pipe-main.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2015-2022 MinIO, Inc.
+// Copyright (c) 2015-2024 MinIO, Inc.
 //
 // This file is part of MinIO Object Storage stack
 //
@@ -18,15 +18,18 @@
 package cmd
 
 import (
+	"fmt"
 	"io"
 	"os"
 	"runtime/debug"
 	"syscall"
 
 	"github.com/dustin/go-humanize"
 	"github.com/minio/cli"
+	json "github.com/minio/colorjson"
 	"github.com/minio/mc/pkg/probe"
 	"github.com/minio/minio-go/v7"
+	"github.com/minio/pkg/v3/console"
 )
 
 func defaultPartSize() string {
@@ -114,7 +117,28 @@ EXAMPLES:
 `,
 }
 
-func pipe(ctx *cli.Context, targetURL string, encKeyDB map[string][]prefixSSEPair, meta map[string]string, quiet bool) *probe.Error {
+// pipeMessage container for pipe messages
+type pipeMessage struct {
+	Status string `json:"status"`
+	Target string `json:"target"`
+	Size   int64  `json:"size"`
+}
+
+// String colorized pipe message
+func (p pipeMessage) String() string {
+	return console.Colorize("Pipe", fmt.Sprintf("%d bytes -> `%s`", p.Size, p.Target))
+}
+
+// JSON jsonified pipe message
+func (p pipeMessage) JSON() string {
+	p.Status = "success"
+	pipeMessageBytes, e := json.MarshalIndent(p, "", " ")
+	fatalIf(probe.NewError(e), "Unable to marshal into JSON.")
+
+	return string(pipeMessageBytes)
+}
+
+func pipe(ctx *cli.Context, targetURL string, encKeyDB map[string][]prefixSSEPair, meta map[string]string, quiet bool, json bool) *probe.Error {
 	// If possible increase the pipe buffer size
 	if e := increasePipeBufferSize(os.Stdin, ctx.Int("pipe-max-size")); e != nil {
 		fatalIf(probe.NewError(e), "Unable to increase custom pipe-max-size")
@@ -159,21 +183,26 @@ func pipe(ctx *cli.Context, targetURL string, encKeyDB map[string][]prefixSSEPai
 	}
 
 	var reader io.Reader
-	if !quiet {
+	if !quiet && !json {
 		pg := newProgressBar(0)
 		reader = io.TeeReader(os.Stdin, pg)
 	} else {
 		reader = os.Stdin
 	}
 
-	_, err := putTargetStreamWithURL(targetURL, reader, -1, opts)
+	n, err := putTargetStreamWithURL(targetURL, reader, -1, opts)
 	// TODO: See if this check is necessary.
 	switch e := err.ToGoError().(type) {
 	case *os.PathError:
 		if e.Err == syscall.EPIPE {
 			// stdin closed by the user. Gracefully exit.
 			return nil
 		}
+	case nil:
+		printMsg(pipeMessage{
+			Target: targetURL,
+			Size:   n,
+		})
 	}
 	return err.Trace(targetURL)
 }
@@ -193,8 +222,10 @@ func mainPipe(ctx *cli.Context) error {
 	encKeyDB, err := validateAndCreateEncryptionKeys(ctx)
 	fatalIf(err, "Unable to parse encryption keys.")
 
-	// globalQuiet is true for no window size to get. We just need --quiet here.
+	// globalQuiet is true for no window size to get.
+	// We just need --quiet and --json here.
 	quiet := ctx.Bool("quiet")
+	json := ctx.Bool("json")
 
 	meta := map[string]string{}
 	if attr := ctx.String("attr"); attr != "" {
@@ -205,12 +236,12 @@ func mainPipe(ctx *cli.Context) error {
 		meta["X-Amz-Tagging"] = tags
 	}
 	if len(ctx.Args()) == 0 {
-		err = pipe(ctx, "", nil, meta, quiet)
+		err = pipe(ctx, "", nil, meta, quiet, json)
 		fatalIf(err.Trace("stdout"), "Unable to write to one or more targets.")
 	} else {
 		// extract URLs.
 		URLs := ctx.Args()
-		err = pipe(ctx, URLs[0], encKeyDB, meta, quiet)
+		err = pipe(ctx, URLs[0], encKeyDB, meta, quiet, json)
 		fatalIf(err.Trace(URLs[0]), "Unable to write to one or more targets.")
 	}