first with full handle over rpm

Signed-off-by: GnomeZworc <nicolas.boufidjeline@g3e.fr>

internal/clone/rpm/cloner.go

@@ -0,0 +1,195 @@
+package rpm
+
+import (
+	"compress/gzip"
+	"context"
+	"encoding/xml"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+type Progress struct {
+	File      string
+	BytesDone int64
+}
+
+type ProgressFunc func(p Progress)
+
+type Cloner struct {
+	SourceURL  string
+	DestDir    string
+	HTTPClient *http.Client
+	OnProgress ProgressFunc
+}
+
+func New(sourceURL, destDir string) *Cloner {
+	return &Cloner{
+		SourceURL:  strings.TrimRight(sourceURL, "/"),
+		DestDir:    destDir,
+		HTTPClient: &http.Client{Timeout: 30 * time.Minute},
+	}
+}
+
+func (c *Cloner) Clone(ctx context.Context) error {
+	if err := os.MkdirAll(filepath.Join(c.DestDir, "repodata"), 0o755); err != nil {
+		return fmt.Errorf("create repodata dir: %w", err)
+	}
+	if err := os.MkdirAll(filepath.Join(c.DestDir, "Packages"), 0o755); err != nil {
+		return fmt.Errorf("create Packages dir: %w", err)
+	}
+
+	repomd, err := c.fetchRepoMD(ctx)
+	if err != nil {
+		return fmt.Errorf("fetch repomd.xml: %w", err)
+	}
+
+	var primaryEntry *RepoMDEntry
+	for i, entry := range repomd.Data {
+		if entry.Type == "primary" {
+			primaryEntry = &repomd.Data[i]
+			continue
+		}
+		if err := c.downloadMetadataFile(ctx, entry); err != nil {
+			return fmt.Errorf("download metadata %s: %w", entry.Type, err)
+		}
+	}
+
+	if primaryEntry == nil {
+		return fmt.Errorf("no primary metadata found in repomd.xml")
+	}
+
+	packages, err := c.fetchPrimary(ctx, *primaryEntry)
+	if err != nil {
+		return fmt.Errorf("fetch primary.xml: %w", err)
+	}
+
+	for _, pkg := range packages {
+		if err := ctx.Err(); err != nil {
+			return err
+		}
+		if err := c.downloadPackage(ctx, pkg); err != nil {
+			return fmt.Errorf("download package %s: %w", pkg.Name, err)
+		}
+	}
+
+	return nil
+}
+
+func (c *Cloner) fetchRepoMD(ctx context.Context) (*RepoMD, error) {
+	url := c.SourceURL + "/repodata/repomd.xml"
+	data, err := c.fetchBytes(ctx, url)
+	if err != nil {
+		return nil, err
+	}
+
+	dest := filepath.Join(c.DestDir, "repodata", "repomd.xml")
+	if err := writeFile(dest, data); err != nil {
+		return nil, err
+	}
+
+	var repomd RepoMD
+	if err := xml.Unmarshal(data, &repomd); err != nil {
+		return nil, fmt.Errorf("parse repomd.xml: %w", err)
+	}
+	return &repomd, nil
+}
+
+func (c *Cloner) fetchPrimary(ctx context.Context, entry RepoMDEntry) ([]Package, error) {
+	url := c.SourceURL + "/" + entry.Location.Href
+	data, err := c.fetchBytes(ctx, url)
+	if err != nil {
+		return nil, err
+	}
+
+	if entry.Checksum.Type == "sha256" {
+		if err := verifyChecksum(data, entry.Checksum.Value); err != nil {
+			return nil, fmt.Errorf("primary.xml.gz: %w", err)
+		}
+	}
+
+	dest := filepath.Join(c.DestDir, entry.Location.Href)
+	if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
+		return nil, err
+	}
+	if err := writeFile(dest, data); err != nil {
+		return nil, err
+	}
+
+	gz, err := gzip.NewReader(strings.NewReader(string(data)))
+	if err != nil {
+		return nil, fmt.Errorf("open gzip: %w", err)
+	}
+	defer gz.Close()
+
+	var primary PrimaryMetadata
+	if err := xml.NewDecoder(gz).Decode(&primary); err != nil {
+		return nil, fmt.Errorf("parse primary.xml: %w", err)
+	}
+	return primary.Packages, nil
+}
+
+func (c *Cloner) downloadMetadataFile(ctx context.Context, entry RepoMDEntry) error {
+	url := c.SourceURL + "/" + entry.Location.Href
+	dest := filepath.Join(c.DestDir, entry.Location.Href)
+
+	n, err := c.downloadAndVerify(ctx, url, dest, entry.Checksum.Type, entry.Checksum.Value)
+	if err != nil {
+		return err
+	}
+	if c.OnProgress != nil {
+		c.OnProgress(Progress{File: entry.Location.Href, BytesDone: n})
+	}
+	return nil
+}
+
+func (c *Cloner) downloadPackage(ctx context.Context, pkg Package) error {
+	url := c.SourceURL + "/" + pkg.Location.Href
+	dest := filepath.Join(c.DestDir, pkg.Location.Href)
+
+	if err := os.MkdirAll(filepath.Dir(dest), 0o755); err != nil {
+		return err
+	}
+
+	n, err := c.downloadAndVerify(ctx, url, dest, pkg.Checksum.Type, pkg.Checksum.Value)
+	if err != nil {
+		return err
+	}
+	if c.OnProgress != nil {
+		c.OnProgress(Progress{File: pkg.Location.Href, BytesDone: n})
+	}
+	return nil
+}
+
+func (c *Cloner) downloadAndVerify(ctx context.Context, url, destPath, checksumType, expectedChecksum string) (int64, error) {
+	return DownloadAndVerify(ctx, c.HTTPClient, url, destPath, checksumType, expectedChecksum)
+}
+
+func (c *Cloner) fetchBytes(ctx context.Context, url string) ([]byte, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := c.HTTPClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("HTTP %d for %s", resp.StatusCode, url)
+	}
+	return io.ReadAll(resp.Body)
+}
+
+func writeFile(path string, data []byte) error {
+	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
+		return err
+	}
+	return os.WriteFile(path, data, 0o644)
+}
+