Refactor plugins system

pkg/plugins/downloader.go

@@ -0,0 +1,160 @@
+package plugins
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+	"path"
+	"path/filepath"
+)
+
+// PluginDownloader defines the interface for downloading and validating plugins from remote sources.
+type PluginDownloader interface {
+	// Download downloads a plugin archive and returns its hash.
+	Download(ctx context.Context, pName, pVersion string) (string, error)
+	// Check checks the plugin archive integrity against a known hash.
+	Check(ctx context.Context, pName, pVersion, hash string) error
+}
+
+// RegistryDownloaderOptions holds configuration options for creating a RegistryDownloader.
+type RegistryDownloaderOptions struct {
+	HTTPClient   *http.Client
+	ArchivesPath string
+}
+
+// RegistryDownloader implements PluginDownloader for HTTP-based plugin downloads.
+type RegistryDownloader struct {
+	httpClient *http.Client
+	baseURL    *url.URL
+	archives   string
+}
+
+// NewRegistryDownloader creates a new HTTP-based plugin downloader.
+func NewRegistryDownloader(opts RegistryDownloaderOptions) (*RegistryDownloader, error) {
+	baseURL, err := url.Parse(pluginsURL)
+	if err != nil {
+		return nil, err
+	}
+
+	httpClient := opts.HTTPClient
+	if httpClient == nil {
+		httpClient = http.DefaultClient
+	}
+
+	return &RegistryDownloader{
+		httpClient: httpClient,
+		baseURL:    baseURL,
+		archives:   opts.ArchivesPath,
+	}, nil
+}
+
+// Download downloads a plugin archive.
+func (d *RegistryDownloader) Download(ctx context.Context, pName, pVersion string) (string, error) {
+	filename := d.buildArchivePath(pName, pVersion)
+
+	var hash string
+	_, err := os.Stat(filename)
+	if err != nil && !os.IsNotExist(err) {
+		return "", fmt.Errorf("failed to read archive %s: %w", filename, err)
+	}
+
+	if err == nil {
+		hash, err = computeHash(filename)
+		if err != nil {
+			return "", fmt.Errorf("failed to compute hash: %w", err)
+		}
+	}
+
+	endpoint, err := d.baseURL.Parse(path.Join(d.baseURL.Path, "download", pName, pVersion))
+	if err != nil {
+		return "", fmt.Errorf("failed to parse endpoint URL: %w", err)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint.String(), nil)
+	if err != nil {
+		return "", fmt.Errorf("failed to create request: %w", err)
+	}
+
+	if hash != "" {
+		req.Header.Set(hashHeader, hash)
+	}
+
+	resp, err := d.httpClient.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("failed to call service: %w", err)
+	}
+
+	defer func() { _ = resp.Body.Close() }()
+
+	switch resp.StatusCode {
+	case http.StatusNotModified:
+		return hash, nil
+	case http.StatusOK:
+		err = os.MkdirAll(filepath.Dir(filename), 0o755)
+		if err != nil {
+			return "", fmt.Errorf("failed to create directory: %w", err)
+		}
+
+		var file *os.File
+		file, err = os.Create(filename)
+		if err != nil {
+			return "", fmt.Errorf("failed to create file %q: %w", filename, err)
+		}
+
+		defer func() { _ = file.Close() }()
+
+		_, err = io.Copy(file, resp.Body)
+		if err != nil {
+			return "", fmt.Errorf("failed to write response: %w", err)
+		}
+
+		hash, err = computeHash(filename)
+		if err != nil {
+			return "", fmt.Errorf("failed to compute hash: %w", err)
+		}
+	default:
+		data, _ := io.ReadAll(resp.Body)
+		return "", fmt.Errorf("error: %d: %s", resp.StatusCode, string(data))
+	}
+
+	return hash, nil
+}
+
+// Check checks the plugin archive integrity.
+func (d *RegistryDownloader) Check(ctx context.Context, pName, pVersion, hash string) error {
+	endpoint, err := d.baseURL.Parse(path.Join(d.baseURL.Path, "validate", pName, pVersion))
+	if err != nil {
+		return fmt.Errorf("failed to parse endpoint URL: %w", err)
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint.String(), nil)
+	if err != nil {
+		return fmt.Errorf("failed to create request: %w", err)
+	}
+
+	if hash != "" {
+		req.Header.Set(hashHeader, hash)
+	}
+
+	resp, err := d.httpClient.Do(req)
+	if err != nil {
+		return fmt.Errorf("failed to call service: %w", err)
+	}
+
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode == http.StatusOK {
+		return nil
+	}
+
+	return errors.New("plugin integrity check failed")
+}
+
+// buildArchivePath builds the path to a plugin archive file.
+func (d *RegistryDownloader) buildArchivePath(pName, pVersion string) string {
+	return filepath.Join(d.archives, filepath.FromSlash(pName), pVersion+".zip")
+}