dotcloud/docker

package client // import "github.com/docker/docker/client"

import (
    "context"
    "net/url"

    "github.com/distribution/reference"
    "github.com/pkg/errors"
)

// ImageTag tags an image in the docker host
func (cli *Client) ImageTag(ctx context.Context, source, target string) error {
    if _, err := reference.ParseAnyReference(source); err != nil {
        return errors.Wrapf(err, "Error parsing reference: %q is not a valid repository/tag", source)
    }

    ref, err := reference.ParseNormalizedNamed(target)
    if err != nil {
        return errors.Wrapf(err, "Error parsing reference: %q is not a valid repository/tag", target)
    }

    if _, isCanonical := ref.(reference.Canonical); isCanonical {
        return errors.New("refusing to create a tag with a digest reference")
    }

    ref = reference.TagNameOnly(ref)

    query := url.Values{}
    query.Set("repo", reference.FamiliarName(ref))
    if tagged, ok := ref.(reference.Tagged); ok {
        query.Set("tag", tagged.Tag())
    }

    resp, err := cli.post(ctx, "/images/"+source+"/tag", query, nil, nil)
    ensureReaderClosed(resp)
    return err
}