a4fadc596b
Now that we have most of the services required for use with containerd, it was found that common patterns were used throughout services. By defining a central `errdefs` package, we ensure that services will map errors to and from grpc consistently and cleanly. One can decorate an error with as much context as necessary, using `pkg/errors` and still have the error mapped correctly via grpc. We make a few sacrifices. At this point, the common errors we use across the repository all map directly to grpc error codes. While this seems positively crazy, it actually works out quite well. The error conditions that were specific weren't super necessary and the ones that were necessary now simply have better context information. We lose the ability to add new codes, but this constraint may not be a bad thing. Effectively, as long as one uses the errors defined in `errdefs`, the error class will be mapped correctly across the grpc boundary and everything will be good. If you don't use those definitions, the error maps to "unknown" and the error message is preserved. Signed-off-by: Stephen J Day <stephen.day@docker.com>
115 lines
2.4 KiB
Go
115 lines
2.4 KiB
Go
package content
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import (
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"io"
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contentapi "github.com/containerd/containerd/api/services/content/v1"
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"github.com/containerd/containerd/content"
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"github.com/containerd/containerd/errdefs"
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digest "github.com/opencontainers/go-digest"
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"github.com/pkg/errors"
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)
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type remoteWriter struct {
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ref string
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client contentapi.Content_WriteClient
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offset int64
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digest digest.Digest
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}
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// send performs a synchronous req-resp cycle on the client.
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func (rw *remoteWriter) send(req *contentapi.WriteContentRequest) (*contentapi.WriteContentResponse, error) {
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if err := rw.client.Send(req); err != nil {
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return nil, err
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}
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resp, err := rw.client.Recv()
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if err == nil {
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// try to keep these in sync
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if resp.Digest != "" {
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rw.digest = resp.Digest
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}
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}
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return resp, err
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}
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func (rw *remoteWriter) Status() (content.Status, error) {
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resp, err := rw.send(&contentapi.WriteContentRequest{
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Action: contentapi.WriteActionStat,
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})
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if err != nil {
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return content.Status{}, err
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}
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return content.Status{
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Ref: rw.ref,
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Offset: resp.Offset,
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StartedAt: resp.StartedAt,
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UpdatedAt: resp.UpdatedAt,
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}, nil
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}
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func (rw *remoteWriter) Digest() digest.Digest {
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return rw.digest
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}
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func (rw *remoteWriter) Write(p []byte) (n int, err error) {
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offset := rw.offset
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resp, err := rw.send(&contentapi.WriteContentRequest{
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Action: contentapi.WriteActionWrite,
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Offset: offset,
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Data: p,
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})
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if err != nil {
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return 0, err
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}
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n = int(resp.Offset - offset)
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if n < len(p) {
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err = io.ErrShortWrite
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}
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rw.offset += int64(n)
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if resp.Digest != "" {
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rw.digest = resp.Digest
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}
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return
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}
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func (rw *remoteWriter) Commit(size int64, expected digest.Digest) error {
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resp, err := rw.send(&contentapi.WriteContentRequest{
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Action: contentapi.WriteActionCommit,
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Total: size,
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Offset: rw.offset,
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Expected: expected,
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})
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if err != nil {
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return errdefs.FromGRPC(err)
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}
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if size != 0 && resp.Offset != size {
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return errors.Errorf("unexpected size: %v != %v", resp.Offset, size)
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}
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if expected != "" && resp.Digest != expected {
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return errors.Errorf("unexpected digest: %v != %v", resp.Digest, expected)
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}
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rw.digest = resp.Digest
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rw.offset = resp.Offset
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return nil
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}
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func (rw *remoteWriter) Truncate(size int64) error {
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// This truncation won't actually be validated until a write is issued.
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rw.offset = size
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return nil
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}
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func (rw *remoteWriter) Close() error {
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return rw.client.CloseSend()
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}
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