github.com/fabiokung/docker@v0.11.2-0.20170222101415-4534dcd49497/client/image_pull.go (about) 1 package client 2 3 import ( 4 "io" 5 "net/http" 6 "net/url" 7 8 "golang.org/x/net/context" 9 10 "github.com/docker/distribution/reference" 11 "github.com/docker/docker/api/types" 12 ) 13 14 // ImagePull requests the docker host to pull an image from a remote registry. 15 // It executes the privileged function if the operation is unauthorized 16 // and it tries one more time. 17 // It's up to the caller to handle the io.ReadCloser and close it properly. 18 // 19 // FIXME(vdemeester): there is currently used in a few way in docker/docker 20 // - if not in trusted content, ref is used to pass the whole reference, and tag is empty 21 // - if in trusted content, ref is used to pass the reference name, and tag for the digest 22 func (cli *Client) ImagePull(ctx context.Context, refStr string, options types.ImagePullOptions) (io.ReadCloser, error) { 23 ref, err := reference.ParseNormalizedNamed(refStr) 24 if err != nil { 25 return nil, err 26 } 27 28 query := url.Values{} 29 query.Set("fromImage", reference.FamiliarName(ref)) 30 if !options.All { 31 query.Set("tag", getAPITagFromNamedRef(ref)) 32 } 33 34 resp, err := cli.tryImageCreate(ctx, query, options.RegistryAuth) 35 if resp.statusCode == http.StatusUnauthorized && options.PrivilegeFunc != nil { 36 newAuthHeader, privilegeErr := options.PrivilegeFunc() 37 if privilegeErr != nil { 38 return nil, privilegeErr 39 } 40 resp, err = cli.tryImageCreate(ctx, query, newAuthHeader) 41 } 42 if err != nil { 43 return nil, err 44 } 45 return resp.body, nil 46 } 47 48 // getAPITagFromNamedRef returns a tag from the specified reference. 49 // This function is necessary as long as the docker "server" api expects 50 // digests to be sent as tags and makes a distinction between the name 51 // and tag/digest part of a reference. 52 func getAPITagFromNamedRef(ref reference.Named) string { 53 if digested, ok := ref.(reference.Digested); ok { 54 return digested.Digest().String() 55 } 56 ref = reference.TagNameOnly(ref) 57 if tagged, ok := ref.(reference.Tagged); ok { 58 return tagged.Tag() 59 } 60 return "" 61 }