WIP: add first run at app rollback command

See coop-cloud/organising#146.

cli/app/rollback.go

@@ -3,19 +3,27 @@ package app
 import (
 	"fmt"
 
+	"context"
+
 	"coopcloud.tech/abra/pkg/config"
+
+	"coopcloud.tech/abra/cli/internal"
+	appPkg "coopcloud.tech/abra/pkg/app"
+	"coopcloud.tech/abra/pkg/catalogue"
+	"coopcloud.tech/abra/pkg/client"
+	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli/v2"
 )
 
 var appRollbackCommand = &cli.Command{
 	Name:      "rollback",
 	Usage:     "Roll an app back to a previous version",
-	Aliases:   []string{"b"},
+	Aliases:   []string{"r"},
 	ArgsUsage: "[<version>]",
 	BashComplete: func(c *cli.Context) {
 		appNames, err := config.GetAppNames()
 		if err != nil {
-			return
+			logrus.Warn(err)
 		}
 		if c.NArg() > 0 {
 			return
@@ -24,4 +32,49 @@ var appRollbackCommand = &cli.Command{
 			fmt.Println(a)
 		}
 	},
+	Action: func(c *cli.Context) error {
+		app := internal.ValidateApp(c)
+
+		ctx := context.Background()
+		cl, err := client.New(app.Server)
+		if err != nil {
+			logrus.Fatal(err)
+		}
+
+		recipeMeta, err := catalogue.GetRecipeMeta(app.Type)
+		if err != nil {
+			logrus.Fatal(err)
+		}
+		if len(recipeMeta.Versions) == 0 {
+			logrus.Fatalf("no catalogue versions available for '%s'", app.Type)
+		}
+
+		deployedVersions, isDeployed, err := appPkg.DeployedVersions(ctx, cl, app)
+		if err != nil {
+			logrus.Fatal(err)
+		}
+		if !isDeployed {
+			logrus.Fatalf("'%s' is not deployed?", app.Name)
+		}
+		if _, exists := deployedVersions["app"]; !exists {
+			logrus.Fatalf("no versioned 'app' service for '%s', cannot determine version", app.Name)
+		}
+
+		version := c.Args().Get(1)
+		if version == "" {
+			// TODO:
+			// using deployedVersions["app"], get index+1 version from catalogue
+			// otherwise bail out saying there is nothing to rollback to
+		} else {
+			// TODO
+			// ensure this version is listed in the catalogue
+			// ensure this version is "older" (lower down in the list)
+		}
+
+		// TODO
+		// display table of existing state and expected state and prompt
+		// run the deployment with this target version!
+
+		return nil
+	},
 }