feat: Moved preheatImage struct and parseManifestURL from manager/job/types.go to internal/job/image.go for better encapsulation

Signed-off-by: Gaius <gaius.qi@gmail.com>

Author: gaius-qi

internal/job/image.go

@@ -0,0 +1,397 @@
+/*
+ *     Copyright 2025 The Dragonfly 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 job
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"regexp"
+	"time"
+
+	"github.com/containerd/containerd/platforms"
+	"github.com/docker/distribution"
+	"github.com/docker/distribution/manifest/manifestlist"
+	"github.com/docker/distribution/manifest/ocischema"
+	"github.com/docker/distribution/manifest/schema1"
+	"github.com/docker/distribution/manifest/schema2"
+	registryclient "github.com/docker/distribution/registry/client"
+	"github.com/docker/distribution/registry/client/auth"
+	"github.com/docker/distribution/registry/client/transport"
+	typesregistry "github.com/docker/docker/api/types/registry"
+	"github.com/docker/docker/registry"
+	specs "github.com/opencontainers/image-spec/specs-go/v1"
+	"go.opentelemetry.io/otel/trace"
+
+	"d7y.io/dragonfly/v2/manager/config"
+	"d7y.io/dragonfly/v2/manager/types"
+	nethttp "d7y.io/dragonfly/v2/pkg/net/http"
+)
+
+// defaultHTTPTransport is the default http transport.
+var defaultHTTPTransport = &http.Transport{
+	MaxIdleConns:        400,
+	MaxIdleConnsPerHost: 20,
+	MaxConnsPerHost:     50,
+	IdleConnTimeout:     120 * time.Second,
+}
+
+// accessURLRegexp is the regular expression for parsing access url.
+var accessURLRegexp, _ = regexp.Compile("^(.*)://(.*)/v2/(.*)/manifests/(.*)")
+
+// preheatImage is image information for preheat.
+type preheatImage struct {
+	protocol string
+	domain   string
+	name     string
+	tag      string
+}
+
+func (p *preheatImage) manifestURL() string {
+	return fmt.Sprintf("%s://%s/v2/%s/manifests/%s", p.protocol, p.domain, p.name, p.tag)
+}
+
+func (p *preheatImage) blobsURL(digest string) string {
+	return fmt.Sprintf("%s://%s/v2/%s/blobs/%s", p.protocol, p.domain, p.name, digest)
+}
+
+// parseManifestURL parses a container image manifest URL into its components.
+// It extracts the protocol, domain, image name, and tag from the provided URL
+// using a regular expression.
+func parseManifestURL(url string) (*preheatImage, error) {
+	r := accessURLRegexp.FindStringSubmatch(url)
+	if len(r) != 5 {
+		return nil, errors.New("parse access url failed")
+	}
+
+	return &preheatImage{
+		protocol: r[1],
+		domain:   r[2],
+		name:     r[3],
+		tag:      r[4],
+	}, nil
+}
+
+// CreatePreheatRequestsByManifestURL generates a list of preheat requests for a container image
+// by fetching and parsing its manifest from a registry. It handles authentication, platform-specific
+// manifest filtering, and layer extraction for preheating.
+func CreatePreheatRequestsByManifestURL(ctx context.Context, args types.PreheatArgs, registryTimeout time.Duration, rootCAs *x509.CertPool, insecureSkipVerify bool) ([]PreheatRequest, error) {
+	ctx, span := tracer.Start(ctx, config.SpanGetLayers, trace.WithSpanKind(trace.SpanKindProducer))
+	defer span.End()
+
+	// Parse image manifest url.
+	image, err := parseManifestURL(args.URL)
+	if err != nil {
+		return nil, err
+	}
+
+	// Background:
+	// Harbor uses the V1 preheat request and will carry the auth info in the headers.
+	options := []imageAuthClientOption{}
+	header := nethttp.MapToHeader(args.Headers)
+	if token := header.Get("Authorization"); len(token) > 0 {
+		options = append(options, withIssuedToken(token))
+		header.Set("Authorization", token)
+	}
+
+	httpClient := &http.Client{
+		Timeout: registryTimeout,
+		Transport: &http.Transport{
+			DialContext:         nethttp.NewSafeDialer().DialContext,
+			TLSClientConfig:     &tls.Config{RootCAs: rootCAs, InsecureSkipVerify: insecureSkipVerify},
+			MaxIdleConns:        defaultHTTPTransport.MaxIdleConns,
+			MaxIdleConnsPerHost: defaultHTTPTransport.MaxIdleConnsPerHost,
+			MaxConnsPerHost:     defaultHTTPTransport.MaxConnsPerHost,
+			IdleConnTimeout:     defaultHTTPTransport.IdleConnTimeout,
+		},
+	}
+
+	// Init docker auth client.
+	client, err := newImageAuthClient(image, httpClient, &typesregistry.AuthConfig{Username: args.Username, Password: args.Password}, options...)
+	if err != nil {
+		return nil, err
+	}
+
+	// Get platform.
+	platform := platforms.DefaultSpec()
+	if args.Platform != "" {
+		platform, err = platforms.Parse(args.Platform)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	// Resolve manifests for the image.
+	manifests, err := resolveManifests(ctx, client, image, header.Clone(), platform)
+	if err != nil {
+		return nil, err
+	}
+
+	// No matching manifest for platform in the manifest list entries
+	if len(manifests) == 0 {
+		return nil, fmt.Errorf("no matching manifest for platform %s", platforms.Format(platform))
+	}
+
+	// Set authorization header
+	header.Set("Authorization", client.GetAuthToken())
+
+	// Build preheat requests for container image layers from the provided manifests.
+	req, err := buildPreheatRequestFromManifests(manifests, args, header.Clone(), image, rootCAs, insecureSkipVerify)
+	if err != nil {
+		return nil, err
+	}
+
+	return req, nil
+}
+
+// resolveManifests fetches and resolves container image manifests from a registry for a specified platform.
+// It constructs an HTTP request to retrieve the manifest, handles authentication via headers, and processes the response
+// to return manifests matching the given platform. Supports single manifests and manifest lists.
+func resolveManifests(ctx context.Context, client *imageAuthClient, image *preheatImage, header http.Header, platform specs.Platform) ([]distribution.Manifest, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, image.manifestURL(), nil)
+	if err != nil {
+		return nil, err
+	}
+
+	// Set header from the user request.
+	for key, values := range header {
+		for _, value := range values {
+			req.Header.Add(key, value)
+		}
+	}
+
+	// Set accept header with media types.
+	for _, mediaType := range distribution.ManifestMediaTypes() {
+		req.Header.Add("Accept", mediaType)
+	}
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	// Handle response.
+	if resp.StatusCode == http.StatusNotModified {
+		return nil, distribution.ErrManifestNotModified
+	} else if !registryclient.SuccessStatus(resp.StatusCode) {
+		return nil, registryclient.HandleErrorResponse(resp)
+	}
+
+	ctHeader := resp.Header.Get("Content-Type")
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	// Unmarshal manifest.
+	manifest, _, err := distribution.UnmarshalManifest(ctHeader, body)
+	if err != nil {
+		return nil, err
+	}
+
+	switch v := manifest.(type) {
+	case *schema1.SignedManifest, *schema2.DeserializedManifest, *ocischema.DeserializedManifest:
+		return []distribution.Manifest{v}, nil
+	case *manifestlist.DeserializedManifestList:
+		var result []distribution.Manifest
+		for _, v := range filterManifests(v.Manifests, platform) {
+			image.tag = v.Digest.String()
+			manifests, err := resolveManifests(ctx, client, image, header.Clone(), platform)
+			if err != nil {
+				return nil, err
+			}
+
+			result = append(result, manifests...)
+		}
+
+		return result, nil
+	}
+
+	return nil, errors.New("unknown manifest type")
+}
+
+// filterManifests filters a list of manifest descriptors to return only those matching the specified platform.
+// It compares the architecture and operating system of each manifest descriptor against the target platform.
+func filterManifests(manifests []manifestlist.ManifestDescriptor, platform specs.Platform) []manifestlist.ManifestDescriptor {
+	var matches []manifestlist.ManifestDescriptor
+	for _, desc := range manifests {
+		if desc.Platform.Architecture == platform.Architecture && desc.Platform.OS == platform.OS {
+			matches = append(matches, desc)
+		}
+	}
+
+	return matches
+}
+
+// buildPreheatRequestFromManifests constructs preheat requests for container image layers from
+// the provided manifests. It extracts layer URLs from the manifests and builds a PreheatRequest
+// using the specified arguments, headers, and TLS settings.
+func buildPreheatRequestFromManifests(manifests []distribution.Manifest, args types.PreheatArgs, header http.Header, image *preheatImage, rootCAs *x509.CertPool, insecureSkipVerify bool) ([]PreheatRequest, error) {
+	var certificateChain [][]byte
+	if rootCAs != nil {
+		certificateChain = rootCAs.Subjects()
+	}
+
+	var layerURLs []string
+	for _, m := range manifests {
+		for _, v := range m.References() {
+			header.Set("Accept", v.MediaType)
+			layerURLs = append(layerURLs, image.blobsURL(v.Digest.String()))
+		}
+	}
+
+	layers := PreheatRequest{
+		URLs:                layerURLs,
+		PieceLength:         args.PieceLength,
+		Tag:                 args.Tag,
+		Application:         args.Application,
+		FilteredQueryParams: args.FilteredQueryParams,
+		Headers:             nethttp.HeaderToMap(header),
+		Scope:               args.Scope,
+		IPs:                 args.IPs,
+		Percentage:          args.Percentage,
+		Count:               args.Count,
+		ConcurrentTaskCount: args.ConcurrentTaskCount,
+		ConcurrentPeerCount: args.ConcurrentPeerCount,
+		CertificateChain:    certificateChain,
+		InsecureSkipVerify:  insecureSkipVerify,
+		Timeout:             args.Timeout,
+	}
+
+	return []PreheatRequest{layers}, nil
+}
+
+// imageAuthClientOption is an option for imageAuthClient.
+type imageAuthClientOption func(*imageAuthClient)
+
+// withIssuedToken sets the issuedToken for imageAuthClient.
+func withIssuedToken(token string) imageAuthClientOption {
+	return func(c *imageAuthClient) {
+		c.issuedToken = token
+	}
+}
+
+// imageAuthClient is a client for image authentication.
+type imageAuthClient struct {
+	// issuedToken is the issued token specified in header from user request,
+	// there is no need to go through v2 authentication to get a new token
+	// if the token is not empty, just use this token to access v2 API directly.
+	issuedToken string
+
+	// httpClient is the http client.
+	httpClient *http.Client
+
+	// authConfig is the auth config.
+	authConfig *typesregistry.AuthConfig
+
+	// interceptorTokenHandler is the token interceptor.
+	interceptorTokenHandler *interceptorTokenHandler
+}
+
+// newImageAuthClient creates a new imageAuthClient.
+func newImageAuthClient(image *preheatImage, httpClient *http.Client, authConfig *typesregistry.AuthConfig, opts ...imageAuthClientOption) (*imageAuthClient, error) {
+	d := &imageAuthClient{
+		httpClient:              httpClient,
+		authConfig:              authConfig,
+		interceptorTokenHandler: newInterceptorTokenHandler(),
+	}
+
+	for _, opt := range opts {
+		opt(d)
+	}
+
+	if len(d.issuedToken) > 0 {
+		return d, nil
+	}
+
+	// New a challenge manager for the supported authentication types.
+	challengeManager, err := registry.PingV2Registry(&url.URL{Scheme: image.protocol, Host: image.domain}, d.httpClient.Transport)
+	if err != nil {
+		return nil, err
+	}
+
+	// New a credential store which always returns the same credential values.
+	creds := registry.NewStaticCredentialStore(d.authConfig)
+
+	// Transport with authentication.
+	d.httpClient.Transport = transport.NewTransport(
+		d.httpClient.Transport,
+		auth.NewAuthorizer(
+			challengeManager,
+			auth.NewTokenHandlerWithOptions(auth.TokenHandlerOptions{
+				Transport:   d.httpClient.Transport,
+				Credentials: creds,
+				Scopes: []auth.Scope{auth.RepositoryScope{
+					Repository: image.name,
+					Actions:    []string{"pull"},
+				}},
+				ClientID: registry.AuthClientID,
+			}),
+			d.interceptorTokenHandler,
+			auth.NewBasicHandler(creds),
+		),
+	)
+
+	return d, nil
+}
+
+// Do sends an HTTP request and returns an HTTP response.
+func (d *imageAuthClient) Do(req *http.Request) (*http.Response, error) {
+	return d.httpClient.Do(req)
+}
+
+// GetAuthToken returns the bearer token.
+func (d *imageAuthClient) GetAuthToken() string {
+	if len(d.issuedToken) > 0 {
+		return d.issuedToken
+	}
+
+	return d.interceptorTokenHandler.GetAuthToken()
+}
+
+// interceptorTokenHandler is a token interceptor intercept bearer token from auth handler.
+type interceptorTokenHandler struct {
+	auth.AuthenticationHandler
+	token string
+}
+
+// NewInterceptorTokenHandler returns a new InterceptorTokenHandler.
+func newInterceptorTokenHandler() *interceptorTokenHandler {
+	return &interceptorTokenHandler{}
+}
+
+// Scheme returns the authentication scheme.
+func (h *interceptorTokenHandler) Scheme() string {
+	return "bearer"
+}
+
+// AuthorizeRequest sets the Authorization header on the request.
+func (h *interceptorTokenHandler) AuthorizeRequest(req *http.Request, params map[string]string) error {
+	h.token = req.Header.Get("Authorization")
+	return nil
+}
+
+// GetAuthToken returns the bearer token.
+func (h *interceptorTokenHandler) GetAuthToken() string {
+	return h.token
+}