add version command and add build information to metrics

Signed-off-by: David Christofas <dchristofas@owncloud.com>

thumbnails/pkg/command/version.go

@@ -0,0 +1,45 @@
+package command
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/micro/cli/v2"
+	"github.com/micro/go-micro/v2/registry/mdns"
+	tw "github.com/olekukonko/tablewriter"
+	"github.com/owncloud/ocis/thumbnails/pkg/config"
+	"github.com/owncloud/ocis/thumbnails/pkg/flagset"
+)
+
+// PrintVersion prints the service versions of all running instances.
+func PrintVersion(cfg *config.Config) *cli.Command {
+	return &cli.Command{
+		Name:  "version",
+		Usage: "Print the versions of the running instances",
+		Flags: flagset.ListThumbnailsWithConfig(cfg),
+		Action: func(c *cli.Context) error {
+			reg := mdns.NewRegistry()
+			services, err := reg.GetService(cfg.Server.Namespace + "." + cfg.Server.Name)
+			if err != nil {
+				fmt.Println(fmt.Errorf("could not get thumbnails services from the registry: %v", err))
+				return err
+			}
+
+			if len(services) == 0 {
+				fmt.Println("No running thumbnails service found.")
+				return nil
+			}
+
+			table := tw.NewWriter(os.Stdout)
+			table.SetHeader([]string{"Version", "Address", "Id"})
+			table.SetAutoFormatHeaders(false)
+			for _, s := range services {
+				for _, n := range s.Nodes {
+					table.Append([]string{s.Version, n.Address, n.Id})
+				}
+			}
+			table.Render()
+			return nil
+		},
+	}
+}