goat: support input from stdin for repo mst command

cmd/goat/repo.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"strings"
@@ -18,12 +19,12 @@ import (
 	"github.com/bluesky-social/indigo/repo"
 	"github.com/bluesky-social/indigo/util"
 	"github.com/bluesky-social/indigo/xrpc"
-
 	"github.com/ipfs/go-cid"
 	cbor "github.com/ipfs/go-ipld-cbor"
 	ipld "github.com/ipfs/go-ipld-format"
 	"github.com/urfave/cli/v2"
 	"github.com/xlab/treeprint"
+	"golang.org/x/term"
 )
 
 var cmdRepo = &cli.Command{
@@ -226,20 +227,27 @@ func runRepoMST(cctx *cli.Context) error {
 		fullCID: cctx.Bool("full-cid"),
 		root:    cctx.String("root"),
 	}
-	if opts.carPath == "" {
-		return fmt.Errorf("need to provide path to CAR file as argument")
-	}
-	fi, err := os.Open(opts.carPath)
-	if err != nil {
-		return err
+	// determine whether to read from file argument or stdin
+	var inputCAR io.Reader
+	if opts.carPath != "" {
+		fi, err := os.Open(opts.carPath)
+		if err != nil {
+			return err
+		}
+		inputCAR = fi
+	} else {
+		if term.IsTerminal(int(os.Stdin.Fd())) {
+			return fmt.Errorf("need to provide path to CAR file as argument")
+		}
+		inputCAR = os.Stdin
 	}
-
 	// read repository tree in to memory
-	r, err := repo.ReadRepoFromCar(ctx, fi)
+	r, err := repo.ReadRepoFromCar(ctx, inputCAR)
 	if err != nil {
 		return err
 	}
-
+	cst := util.CborStore(r.Blockstore())
+	// determine which root cid to use, defaulting to repo data root
 	rootCID := r.DataCid()
 	if opts.root != "" {
 		optsRootCID, err := cid.Decode(opts.root)
@@ -248,7 +256,7 @@ func runRepoMST(cctx *cli.Context) error {
 		}
 		rootCID = optsRootCID
 	}
-	cst := util.CborStore(r.Blockstore())
+	// start walking mst
 	exists, err := nodeExists(ctx, cst, rootCID)
 	if err != nil {
 		return err
@@ -259,7 +267,7 @@ func runRepoMST(cctx *cli.Context) error {
 			return err
 		}
 	}
-
+	// print tree
 	fmt.Println(tree.String())
 	return nil
 }

go.mod

@@ -69,6 +69,7 @@ require (
 	go.uber.org/zap v1.26.0
 	golang.org/x/crypto v0.21.0
 	golang.org/x/sync v0.7.0
+	golang.org/x/term v0.18.0
 	golang.org/x/text v0.14.0
 	golang.org/x/time v0.3.0
 	golang.org/x/tools v0.15.0

go.sum

@@ -915,6 +915,8 @@ golang.org/x/term v0.4.0/go.mod h1:9P2UbLfCdcvo3p/nzKvsmas4TnlujnuoV9hGgYzW1lQ=
 golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
 golang.org/x/term v0.8.0/go.mod h1:xPskH00ivmX89bAKVGSKKtLOWNx2+17Eiy94tnKShWo=
 golang.org/x/term v0.11.0/go.mod h1:zC9APTIj3jG3FdV/Ons+XE1riIZXG4aZ4GTHiPZJPIU=
+golang.org/x/term v0.18.0 h1:FcHjZXDMxI8mM3nwhX9HlKop4C0YQvCVCdwYl2wOtE8=
+golang.org/x/term v0.18.0/go.mod h1:ILwASektA3OnRv7amZ1xhE/KTR+u50pbXfZ03+6Nx58=
 golang.org/x/text v0.0.0-20170915032832-14c0d48ead0c/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.1-0.20180807135948-17ff2d5776d2/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=