Debian remote repository - inital fetching.

debian/remote.go

@@ -0,0 +1,98 @@
+// Package debian implements Debian-specific repository handling
+package debian
+
+import (
+	"fmt"
+	"github.com/smira/aptly/utils"
+	debc "github.com/smira/godebiancontrol"
+	"net/url"
+	"strings"
+)
+
+// RemoteRepo represents remote (fetchable) Debian repository.
+//
+// Repostitory could be filtered when fetching by components, architectures
+// TODO: support flat format
+type RemoteRepo struct {
+	ArchiveRoot    string
+	Distribution   string
+	Components     []string
+	Architectures  []string
+	archiveRootURL *url.URL
+}
+
+// NewRemoteRepo creates new instance of Debian remote repository with specified params
+func NewRemoteRepo(archiveRoot string, distribution string, components []string, architectures []string) (*RemoteRepo, error) {
+	result := &RemoteRepo{
+		ArchiveRoot:   archiveRoot,
+		Distribution:  distribution,
+		Components:    components,
+		Architectures: architectures,
+	}
+
+	var err error
+
+	result.archiveRootURL, err = url.Parse(archiveRoot)
+	if err != nil {
+		return nil, err
+	}
+
+	return result, nil
+}
+
+// String interface
+func (repo *RemoteRepo) String() string {
+	return fmt.Sprintf("%s %s", repo.ArchiveRoot, repo.Distribution)
+}
+
+// ReleaseURL returns URL to Release file in repo root
+// TODO: InRelease, Release.gz, Release.bz2 handling
+func (repo *RemoteRepo) ReleaseURL() *url.URL {
+	path := &url.URL{Path: fmt.Sprintf("dists/%s/Release", repo.Distribution)}
+	return repo.archiveRootURL.ResolveReference(path)
+}
+
+// Fetch updates information about repository
+func (repo *RemoteRepo) Fetch(d utils.Downloader) error {
+	// Download release file to temporary URL
+	release, err := d.DownloadTemp(repo.ReleaseURL().String())
+	if err != nil {
+		return err
+	}
+	defer release.Close()
+
+	paras, err := debc.Parse(release)
+	if err != nil {
+		return err
+	}
+
+	if len(paras) != 1 {
+		return fmt.Errorf("wrong number of parts in Release file")
+	}
+
+	para := paras[0]
+
+	architectures := strings.Split(para["Architectures"], " ")
+	if len(repo.Architectures) == 0 {
+		repo.Architectures = architectures
+	} else {
+		err = utils.StringsIsSubset(repo.Architectures, architectures,
+			fmt.Sprintf("architecture %%s not available in repo %s", repo))
+		if err != nil {
+			return err
+		}
+	}
+
+	components := strings.Split(para["Components"], " ")
+	if len(repo.Components) == 0 {
+		repo.Components = components
+	} else {
+		err = utils.StringsIsSubset(repo.Components, components,
+			fmt.Sprintf("component %%s not available in repo %s", repo))
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}