Add update command to update from git tags

Signed-off-by: Knut Ahlers <knut@ahlers.me>

cmd/helper.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"fmt"
 	"io/ioutil"
+	"os"
 
 	yaml "gopkg.in/yaml.v2"
 )
@@ -14,17 +15,26 @@ type ansibleRoleDefinition struct {
 	Version string `yaml:"version"`
 }
 
-func patchRoleFile(rolesFile string, updates map[string]string) error {
-	var (
-		inFileContent []byte
-		err           error
-	)
-	if inFileContent, err = ioutil.ReadFile(rolesFile); err != nil {
-		return fmt.Errorf("Roles file not found: %s", err)
+func getRoleDefinitions(rolesFile string) ([]ansibleRoleDefinition, error) {
+	rf, err := os.Open(rolesFile)
+	if err != nil {
+		return nil, err
+	}
+	defer rf.Close()
+
+	def := []ansibleRoleDefinition{}
+	return def, yaml.NewDecoder(rf).Decode(&def)
 }
 
+func patchRoleFile(rolesFile string, updates map[string]string) error {
+	inFile, err := os.Open(rolesFile)
+	if err != nil {
+		return fmt.Errorf("Unable to open roles files: %s", err)
+	}
+	defer inFile.Close()
+
 	in := []ansibleRoleDefinition{}
-	if err = yaml.Unmarshal(inFileContent, &in); err != nil {
+	if err = yaml.NewDecoder(inFile).Decode(&in); err != nil {
 		return fmt.Errorf("Unable to parse roles file: %s", err)
 	}
 
@@ -36,13 +46,13 @@ func patchRoleFile(rolesFile string, updates map[string]string) error {
 		}
 	}
 
-	if inFileContent, err = yaml.Marshal(in); err != nil {
+	buf := new(bytes.Buffer)
+	buf.Write([]byte("---\n\n"))
+
+	if err := yaml.NewEncoder(buf).Encode(in); err != nil {
 		return fmt.Errorf("Unable to marshal roles file: %s", err)
 	}
 
-	buf := new(bytes.Buffer)
-	buf.Write([]byte("---\n\n"))
-	buf.Write(inFileContent)
 	buf.Write([]byte("\n...\n"))
 
 	if err = ioutil.WriteFile(rolesFile, buf.Bytes(), 0644); err != nil {

cmd/update.go

@@ -0,0 +1,50 @@
+package cmd
+
+import (
+	"time"
+
+	"github.com/Luzifer/ansible-role-version/tags"
+	log "github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+// updateCmd represents the update command
+var updateCmd = &cobra.Command{
+	Use:   "update",
+	Short: "Seek for updates in git repositories and update the roles file",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		roles, err := getRoleDefinitions(cfg.RolesFile)
+		if err != nil {
+			return err
+		}
+
+		updates := map[string]string{}
+
+		for _, role := range roles {
+			logger := log.WithFields(log.Fields{
+				"role": role.Name,
+			})
+
+			tag, err := tags.GetLatestTag(role.Src, true)
+			if err != nil {
+				logger.WithError(err).Error("Failed to fetch latest tag")
+				continue
+			}
+
+			if tag.Name != role.Version {
+				updates[role.Name] = tag.Name
+				logger.WithFields(log.Fields{
+					"from":     role.Version,
+					"to":       tag.Name,
+					"released": tag.When.Format(time.RFC1123),
+				}).Info("Update queued")
+			}
+		}
+
+		return patchRoleFile(cfg.RolesFile, updates)
+	},
+}
+
+func init() {
+	RootCmd.AddCommand(updateCmd)
+}

tags/tags.go

@@ -0,0 +1,112 @@
+package tags
+
+import (
+	"errors"
+	"io"
+	"sort"
+	"time"
+
+	"gopkg.in/src-d/go-billy.v4/memfs"
+	git "gopkg.in/src-d/go-git.v4"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/storage/memory"
+)
+
+type Tag struct {
+	Name string
+	When time.Time
+}
+
+var (
+	ErrNoTagsFound = errors.New("No tags found")
+)
+
+// GetLatestTag clones a Git repository into memory and resolves latest
+// leightweight or annotated tag from it
+func GetLatestTag(repoURL string, includeLightweight bool) (*Tag, error) {
+	fs := memfs.New()
+	// Git objects storer based on memory
+	storer := memory.NewStorage()
+
+	// Clones the repository into the worktree (fs) and storer all the .git
+	// content into the storer
+	r, _ := git.Clone(storer, fs, &git.CloneOptions{
+		URL: repoURL,
+	})
+
+	tags := []Tag{}
+
+	// Get reference iterator for all tags
+	it, err := r.Tags()
+	if err != nil {
+		return nil, err
+	}
+	defer it.Close()
+
+	for {
+		ref, err := it.Next()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return nil, err
+		}
+
+		if !ref.Name().IsTag() {
+			continue
+		}
+
+		var when time.Time
+
+		// Check whether the hash is resolvable to a tag
+		if t := tryTag(r, ref.Hash()); t != nil {
+			when = *t
+		}
+
+		// If it wasn't and we may include leightweight tags check for commit
+		if when.IsZero() && includeLightweight {
+			if t := tryCommit(r, ref.Hash()); t != nil {
+				when = *t
+			}
+		}
+
+		if when.IsZero() {
+			// We've resolved no tag
+			continue
+		}
+
+		tags = append(tags, Tag{
+			Name: ref.Name().Short(),
+			When: when,
+		})
+	}
+
+	if len(tags) == 0 {
+		return nil, ErrNoTagsFound
+	}
+
+	// Tags may be unsorted by design so we need to sort them
+	sort.SliceStable(tags, func(i, j int) bool {
+		return tags[i].When.Before(tags[j].When)
+	})
+
+	return &tags[len(tags)-1], nil
+}
+
+func tryTag(r *git.Repository, hash plumbing.Hash) *time.Time {
+	tag, err := r.TagObject(hash)
+	if err != nil {
+		return nil
+	}
+
+	return &tag.Tagger.When
+}
+
+func tryCommit(r *git.Repository, hash plumbing.Hash) *time.Time {
+	commit, err := r.CommitObject(hash)
+	if err != nil {
+		return nil
+	}
+
+	return &commit.Committer.When
+}

tags/tags_test.go

@@ -0,0 +1,12 @@
+package tags
+
+import "log"
+
+func ExampleGetLatestTag() {
+	tag, err := GetLatestTag("https://github.com/luzifer-ansible/deploy-git.git", true)
+	if err != nil {
+		log.Fatalf("Could not resolve latest tag: %s", err)
+	}
+
+	log.Printf("Latest tag: %q, created at %v", tag.Name, tag.When)
+}