feat: Virtual major tags

If enabled in config, each major version will
be shown as a tag. This tag will always link to the
latest release from this version.

This only will consider semantic versions.

Example: v1.0.0, v1.1.0, v2.0.0 => Virtual tags "v1" and "v2" will be shown. "v1" links to "v1.1.0" and "v2" links to "v2.0.0". Pushing a release "v2.0.1" will make "v2" automatically refer to "v2.0.1".

The "v" prefix may be omitted in tags. The virtual tag will also have no "v" prefix then.

Author: saitho

config.yml.dist

@@ -15,6 +15,8 @@ display:
   tags:
     order: desc
     show_date: true
+    virtual_tags:
+        enable_semver_major: true
   index:
     show_branches: true
     show_tags: true

config/config.go

@@ -32,8 +32,11 @@ type Config struct {
 	}
 	Display struct {
 		Tags struct {
-			Order    string `default:"desc" yaml:"order"`
-			ShowDate bool   `default:"true" yaml:"show_date"`
+			Order       string `default:"desc" yaml:"order"`
+			ShowDate    bool   `default:"true" yaml:"show_date"`
+			VirtualTags struct {
+				EnableSemverMajor bool `default:"false" yaml:"enable_semver_major"`
+			} `yaml:"virtual_tags"`
 		}
 		Index struct {
 			ShowBranches bool `default:"true" yaml:"show_branches"`

git/virtual_tags.go

@@ -0,0 +1,39 @@
+package git
+
+import (
+	"fmt"
+	"github.com/saitho/static-git-file-server/utils"
+	"regexp"
+)
+
+var re = regexp.MustCompile(`^(v?\d+)\.\d+\.\d+$`)
+
+func ResolveVirtualTag(gitHandler *GitHandler, virtualTag string) (GitTag, error) {
+	for _, tag := range gitHandler.GetTags() {
+		majorTag := re.FindStringSubmatch(tag.Tag)
+		if len(majorTag) < 2 {
+			continue
+		}
+		if majorTag[1] == virtualTag {
+			return tag, nil
+		}
+	}
+	return GitTag{}, fmt.Errorf("cannot resolve virtual tag")
+}
+
+func InsertVirtualTags(tags []GitTag) []GitTag {
+	var newTags []GitTag
+	var processedMajorTags []string
+	for _, tag := range tags {
+		majorTag := re.FindStringSubmatch(tag.Tag)[1]
+		if len(majorTag) > 0 && !utils.Contains(processedMajorTags, majorTag) {
+			newTags = append(newTags, GitTag{
+				Tag:  majorTag,
+				Date: tag.Date,
+			})
+			processedMajorTags = append(processedMajorTags, majorTag)
+		}
+		newTags = append(newTags, tag)
+	}
+	return newTags
+}

main.go

@@ -4,14 +4,16 @@ package main
 
 import (
 	"flag"
-	"github.com/markbates/pkger"
-	"github.com/saitho/static-git-file-server/rendering"
+	"fmt"
 	"net/http"
 	"strings"
 	"time"
 
+	"github.com/markbates/pkger"
+
 	"github.com/saitho/static-git-file-server/config"
 	"github.com/saitho/static-git-file-server/git"
+	"github.com/saitho/static-git-file-server/rendering"
 	"github.com/saitho/static-git-file-server/webserver"
 )
 
@@ -62,7 +64,29 @@ func main() {
 		resp.Auto(http.StatusOK, content)
 	}
 
+	resolveVirtualMajorTag := func(resp *webserver.Response, req *webserver.Request) {
+		majorVersion := req.Params[0]
+		path := ""
+		if len(req.Params) > 1 {
+			path = req.Params[1]
+		}
+
+		latestTag, err := git.ResolveVirtualTag(gitHandler, majorVersion)
+		if err != nil {
+			resp.Text(http.StatusInternalServerError, fmt.Sprintf("Unable to resolve tag %s", majorVersion))
+			return
+		}
+
+		req.Params = []string{"tag", latestTag.Tag, path}
+		handler(resp, req)
+	}
+
 	server.AddHandler(`^/webhook/github`, webserver.GitHubWebHookEndpoint(cfg, gitHandler))
+	if cfg.Display.Tags.VirtualTags.EnableSemverMajor {
+		server.AddHandler(`^/tag/(v?\d+)/-/(.*)`, resolveVirtualMajorTag)
+		server.AddHandler(`^/tag/(v?\d+)/?$`, resolveVirtualMajorTag)
+	}
+
 	server.AddHandler(`^/(branch|tag)/(.*)/-/(.*)`, handler)
 	server.AddHandler(`^/(branch|tag)/(.*)/?$`, handler)
 	server.AddHandler(`^/$`, func(resp *webserver.Response, req *webserver.Request) {
@@ -87,6 +111,10 @@ func main() {
 			}
 		}
 
+		if cfg.Display.Tags.VirtualTags.EnableSemverMajor {
+			tags = git.InsertVirtualTags(tags)
+		}
+
 		content, err := rendering.RenderTemplate("/tmpl/index.html", IndexTmplParams{
 			Cfg:          cfg,
 			ShowBranches: cfg.Display.Index.ShowBranches,

utils/slice.go

@@ -0,0 +1,10 @@
+package utils
+
+func Contains(arr []string, str string) bool {
+	for _, a := range arr {
+		if a == str {
+			return true
+		}
+	}
+	return false
+}