github.com/hasnat/dolt/go@v0.0.0-20210628190320-9eb5d843fbb7/store/cmd/noms/noms_blob_get.go (about)

     1  // Copyright 2019 Dolthub, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  //
    15  // This file incorporates work covered by the following copyright and
    16  // permission notice:
    17  //
    18  // Copyright 2016 Attic Labs, Inc. All rights reserved.
    19  // Licensed under the Apache License, version 2.0:
    20  // http://www.apache.org/licenses/LICENSE-2.0
    21  
    22  package main
    23  
    24  import (
    25  	"context"
    26  	"fmt"
    27  	"io"
    28  	"os"
    29  	"time"
    30  
    31  	humanize "github.com/dustin/go-humanize"
    32  
    33  	"github.com/dolthub/dolt/go/store/cmd/noms/util"
    34  	"github.com/dolthub/dolt/go/store/config"
    35  	"github.com/dolthub/dolt/go/store/types"
    36  	"github.com/dolthub/dolt/go/store/util/profile"
    37  	"github.com/dolthub/dolt/go/store/util/progressreader"
    38  	"github.com/dolthub/dolt/go/store/util/status"
    39  )
    40  
    41  func nomsBlobGet(ctx context.Context, ds string, filePath string) int {
    42  	cfg := config.NewResolver()
    43  	var blob types.Blob
    44  	if db, val, err := cfg.GetPath(ctx, ds); err != nil {
    45  		util.CheckErrorNoUsage(err)
    46  	} else if val == nil {
    47  		util.CheckErrorNoUsage(fmt.Errorf("No value at %s", ds))
    48  	} else if b, ok := val.(types.Blob); !ok {
    49  		util.CheckErrorNoUsage(fmt.Errorf("Value at %s is not a blob", ds))
    50  	} else {
    51  		defer db.Close()
    52  		blob = b
    53  	}
    54  
    55  	defer profile.MaybeStartProfile().Stop()
    56  
    57  	if filePath == "" {
    58  		blob.Copy(ctx, os.Stdout)
    59  		return 0
    60  	}
    61  
    62  	// Note: overwrites any existing file.
    63  	file, err := os.OpenFile(filePath, os.O_WRONLY|os.O_CREATE, 0644)
    64  	util.CheckErrorNoUsage(err)
    65  	defer file.Close()
    66  
    67  	start := time.Now()
    68  	expected := humanize.Bytes(blob.Len())
    69  
    70  	// Create a pipe so that we can connect a progress reader
    71  	preader, pwriter := io.Pipe()
    72  
    73  	go func() {
    74  		blob.Copy(ctx, pwriter)
    75  		pwriter.Close()
    76  	}()
    77  
    78  	blobReader := progressreader.New(preader, func(seen uint64) {
    79  		elapsed := time.Since(start).Seconds()
    80  		rate := uint64(float64(seen) / elapsed)
    81  		status.Printf("%s of %s written in %ds (%s/s)...", humanize.Bytes(seen), expected, int(elapsed), humanize.Bytes(rate))
    82  	})
    83  
    84  	io.Copy(file, blobReader)
    85  	status.Done()
    86  	return 0
    87  }