server: add sort option

This adds a '--sort' to the 'server' sub-command. Currently there is
only one sort option, which is by create date. I assumed that his is
useful in general, compared to a random order, so I made this the
default.

This is slightly over engineered, but makes it easier to add additional
sorting options later. One that comes to my mind is sorting by tag (some
kind of natsort/semversort).

Signed-off-by: Roland Kammerer <roland.kammerer@linbit.com>

Author: rck

handlers.go

@@ -11,6 +11,7 @@ import (
 	"net/url"
 	"os"
 	"path/filepath"
+	"sort"
 	"strings"
 	"sync"
 	"time"
@@ -28,6 +29,7 @@ type registryController struct {
 	l            sync.Mutex
 	tmpl         *template.Template
 	generateOnly bool
+	repoSortBy   string
 }
 
 type v1Compatibility struct {
@@ -44,6 +46,16 @@ type Repository struct {
 	VulnerabilityReport clair.VulnerabilityReport `json:"vulnerability"`
 }
 
+const (
+	sortByCreateDate = "create-date"
+)
+
+type repoByDate []Repository
+
+func (r repoByDate) Len() int           { return len(r) }
+func (r repoByDate) Less(i, j int) bool { return r[i].Created.Before(r[j].Created) }
+func (r repoByDate) Swap(i, j int)      { r[i], r[j] = r[j], r[i] }
+
 // An AnalysisResult holds all vulnerabilities of a scan
 type AnalysisResult struct {
 	Repositories   []Repository `json:"repositories"`
@@ -228,6 +240,11 @@ func (rc *registryController) generateTagsTemplate(ctx context.Context, repo str
 		result.Repositories = append(result.Repositories, rp)
 	}
 
+	switch rc.repoSortBy {
+	case sortByCreateDate:
+		sort.Sort(sort.Reverse(repoByDate(result.Repositories)))
+	}
+
 	// Execute the template.
 	var buf bytes.Buffer
 	if err := rc.tmpl.ExecuteTemplate(&buf, "tags", result); err != nil {

server.go

@@ -43,6 +43,10 @@ func (cmd *serverCommand) Register(fs *flag.FlagSet) {
 	fs.StringVar(&cmd.assetPath, "asset-path", "", "Path to assets and templates")
 
 	fs.BoolVar(&cmd.generateAndExit, "once", false, "generate the templates once and then exit")
+
+	sortOpts := []string{sortByCreateDate}
+	fs.StringVar(&cmd.repoSortBy, "sort", sortByCreateDate,
+		fmt.Sprintf("generate tag templates sorted by property (one of: %s)", strings.Join(sortOpts, ",")))
 }
 
 type serverCommand struct {
@@ -57,6 +61,7 @@ type serverCommand struct {
 	listenAddress string
 	port          string
 	assetPath     string
+	repoSortBy    string
 }
 
 func (cmd *serverCommand) Run(ctx context.Context, args []string) error {
@@ -66,10 +71,15 @@ func (cmd *serverCommand) Run(ctx context.Context, args []string) error {
 		return err
 	}
 
+	if cmd.repoSortBy != sortByCreateDate {
+		return fmt.Errorf("sort option invalid; '%s' is not valid", cmd.repoSortBy)
+	}
+
 	// Create the registry controller for the handlers.
 	rc := registryController{
 		reg:          r,
 		generateOnly: cmd.generateAndExit,
+		repoSortBy:   cmd.repoSortBy,
 	}
 
 	// Create a clair client if the user passed in a server address.