github.com/containerd/Containerd@v1.4.13/content/proxy/content_writer.go (about)

     1  /*
     2     Copyright The containerd Authors.
     3  
     4     Licensed under the Apache License, Version 2.0 (the "License");
     5     you may not use this file except in compliance with the License.
     6     You may obtain a copy of the License at
     7  
     8         http://www.apache.org/licenses/LICENSE-2.0
     9  
    10     Unless required by applicable law or agreed to in writing, software
    11     distributed under the License is distributed on an "AS IS" BASIS,
    12     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13     See the License for the specific language governing permissions and
    14     limitations under the License.
    15  */
    16  
    17  package proxy
    18  
    19  import (
    20  	"context"
    21  	"io"
    22  
    23  	contentapi "github.com/containerd/containerd/api/services/content/v1"
    24  	"github.com/containerd/containerd/content"
    25  	"github.com/containerd/containerd/errdefs"
    26  	digest "github.com/opencontainers/go-digest"
    27  	"github.com/pkg/errors"
    28  )
    29  
    30  type remoteWriter struct {
    31  	ref    string
    32  	client contentapi.Content_WriteClient
    33  	offset int64
    34  	digest digest.Digest
    35  }
    36  
    37  // send performs a synchronous req-resp cycle on the client.
    38  func (rw *remoteWriter) send(req *contentapi.WriteContentRequest) (*contentapi.WriteContentResponse, error) {
    39  	if err := rw.client.Send(req); err != nil {
    40  		return nil, err
    41  	}
    42  
    43  	resp, err := rw.client.Recv()
    44  
    45  	if err == nil {
    46  		// try to keep these in sync
    47  		if resp.Digest != "" {
    48  			rw.digest = resp.Digest
    49  		}
    50  	}
    51  
    52  	return resp, err
    53  }
    54  
    55  func (rw *remoteWriter) Status() (content.Status, error) {
    56  	resp, err := rw.send(&contentapi.WriteContentRequest{
    57  		Action: contentapi.WriteActionStat,
    58  	})
    59  	if err != nil {
    60  		return content.Status{}, errors.Wrap(errdefs.FromGRPC(err), "error getting writer status")
    61  	}
    62  
    63  	return content.Status{
    64  		Ref:       rw.ref,
    65  		Offset:    resp.Offset,
    66  		Total:     resp.Total,
    67  		StartedAt: resp.StartedAt,
    68  		UpdatedAt: resp.UpdatedAt,
    69  	}, nil
    70  }
    71  
    72  func (rw *remoteWriter) Digest() digest.Digest {
    73  	return rw.digest
    74  }
    75  
    76  func (rw *remoteWriter) Write(p []byte) (n int, err error) {
    77  	offset := rw.offset
    78  
    79  	resp, err := rw.send(&contentapi.WriteContentRequest{
    80  		Action: contentapi.WriteActionWrite,
    81  		Offset: offset,
    82  		Data:   p,
    83  	})
    84  	if err != nil {
    85  		return 0, errors.Wrap(errdefs.FromGRPC(err), "failed to send write")
    86  	}
    87  
    88  	n = int(resp.Offset - offset)
    89  	if n < len(p) {
    90  		err = io.ErrShortWrite
    91  	}
    92  
    93  	rw.offset += int64(n)
    94  	if resp.Digest != "" {
    95  		rw.digest = resp.Digest
    96  	}
    97  	return
    98  }
    99  
   100  func (rw *remoteWriter) Commit(ctx context.Context, size int64, expected digest.Digest, opts ...content.Opt) error {
   101  	var base content.Info
   102  	for _, opt := range opts {
   103  		if err := opt(&base); err != nil {
   104  			return err
   105  		}
   106  	}
   107  	resp, err := rw.send(&contentapi.WriteContentRequest{
   108  		Action:   contentapi.WriteActionCommit,
   109  		Total:    size,
   110  		Offset:   rw.offset,
   111  		Expected: expected,
   112  		Labels:   base.Labels,
   113  	})
   114  	if err != nil {
   115  		return errors.Wrap(errdefs.FromGRPC(err), "commit failed")
   116  	}
   117  
   118  	if size != 0 && resp.Offset != size {
   119  		return errors.Errorf("unexpected size: %v != %v", resp.Offset, size)
   120  	}
   121  
   122  	if expected != "" && resp.Digest != expected {
   123  		return errors.Errorf("unexpected digest: %v != %v", resp.Digest, expected)
   124  	}
   125  
   126  	rw.digest = resp.Digest
   127  	rw.offset = resp.Offset
   128  	return nil
   129  }
   130  
   131  func (rw *remoteWriter) Truncate(size int64) error {
   132  	// This truncation won't actually be validated until a write is issued.
   133  	rw.offset = size
   134  	return nil
   135  }
   136  
   137  func (rw *remoteWriter) Close() error {
   138  	return rw.client.CloseSend()
   139  }