/
resolver.go
165 lines (138 loc) · 3.85 KB
/
resolver.go
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// Copyright 2017 The kubecfg authors
//
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package utils
import (
"bytes"
"context"
"fmt"
"github.com/genuinetools/reg/registry"
"github.com/genuinetools/reg/repoutils"
)
const defaultRegistry = "registry-1.docker.io"
// ImageName represents the parts of a docker image name
type ImageName struct {
// eg: "myregistryhost:5000/fedora/httpd:version1.0"
Registry string // "myregistryhost:5000"
Repository string // "fedora"
Name string // "httpd"
Tag string // "version1.0"
Digest string
}
// String implements the Stringer interface
func (n ImageName) String() string {
buf := bytes.Buffer{}
if n.Registry != "" {
buf.WriteString(n.Registry)
buf.WriteString("/")
}
if n.Repository != "" {
buf.WriteString(n.Repository)
buf.WriteString("/")
}
buf.WriteString(n.Name)
if n.Digest != "" {
buf.WriteString("@")
buf.WriteString(n.Digest)
} else {
buf.WriteString(":")
buf.WriteString(n.Tag)
}
return buf.String()
}
// RegistryRepoName returns the "repository" as used in the registry URL
func (n ImageName) RegistryRepoName() string {
repo := n.Repository
if repo == "" {
repo = "library"
}
return fmt.Sprintf("%s/%s", repo, n.Name)
}
// RegistryURL returns the deduced base URL of the registry for this image
func (n ImageName) RegistryURL() string {
reg := n.Registry
if reg == "" {
reg = defaultRegistry
}
return fmt.Sprintf("https://%s", reg)
}
// ParseImageName parses a docker image into an ImageName struct.
func ParseImageName(image string) (ImageName, error) {
ret := ImageName{}
img, err := registry.ParseImage(image)
if err != nil {
return ret, err
}
ret.Registry = img.Domain
ret.Name = img.Path
ret.Digest = img.Digest.String()
ret.Tag = img.Tag
return ret, nil
}
// Resolver is able to resolve docker image names into more specific forms
type Resolver interface {
Resolve(image *ImageName) error
}
// NewIdentityResolver returns a resolver that does only trivial
// :latest canonicalisation
func NewIdentityResolver() Resolver {
return identityResolver{}
}
type identityResolver struct{}
func (r identityResolver) Resolve(image *ImageName) error {
return nil
}
// NewRegistryResolver returns a resolver that looks up a docker
// registry to resolve digests
func NewRegistryResolver(opt registry.Opt) Resolver {
return ®istryResolver{
opt: opt,
cache: make(map[string]string),
}
}
type registryResolver struct {
opt registry.Opt
cache map[string]string
}
func (r *registryResolver) Resolve(n *ImageName) error {
// TODO: get context from caller.
ctx := context.Background()
if n.Digest != "" {
// Already has explicit digest
return nil
}
if digest, ok := r.cache[n.String()]; ok {
n.Digest = digest
return nil
}
img, err := registry.ParseImage(n.String())
if err != nil {
return fmt.Errorf("unable to parse image name: %v", err)
}
auth, err := repoutils.GetAuthConfig("", "", img.Domain)
if err != nil {
return fmt.Errorf("unable to get auth config for registry: %v", err)
}
c, err := registry.New(ctx, auth, r.opt)
if err != nil {
return fmt.Errorf("unable to create registry client: %v", err)
}
digest, err := c.Digest(ctx, img)
if err != nil {
return fmt.Errorf("unable to get digest from the registry: %v", err)
}
n.Digest = digest.String()
r.cache[n.String()] = n.Digest
return nil
}