cluster: Ensure we handle upgrades from snapshots gracefully

Signed-off-by: Dario Freddi <dario.freddi@ispirata.com>

cmd/cluster/upgrade_operator.go

@@ -85,6 +85,20 @@ func clusterUpgradeOperatorF(command *cobra.Command, args []string) error {
 		fmt.Printf("You're currently running Astarte Operator version %s, no updates are available.\n", currentAstarteOperatorVersion)
 		return nil
 	}
+	if isUnstableVersion(currentAstarteOperatorVersion.Original()) {
+		baseVersion, err := getBaseVersionFromUnstable(currentAstarteOperatorVersion.Original())
+		if err != nil {
+			fmt.Println("Your cluster is currently running on snapshot - honestly, there isn't much I can do. If you're running a production cluster, I really hope you know what you're doing.")
+			fmt.Println("In case you didn't really mean to run on the most unstable thing you could run on, I strongly suggest running astartectl cluster uninstall-operator and astartectl cluster install-operator.")
+			os.Exit(1)
+		}
+		currentAstarteOperatorVersion, err = semver.NewVersion(baseVersion)
+		if err != nil {
+			fmt.Println(err)
+			os.Exit(1)
+		}
+		fmt.Printf("Your cluster is currently running on an unstable snapshot - which, by the way, is a bad idea. I'm happy to reconcile you to something more stable, and I'm assuming you're upgrading from %s.\n", currentAstarteOperatorVersion)
+	}
 	fmt.Printf("Will upgrade Astarte Operator to version %s.\n", version)
 
 	if !nonInteractive {

cmd/cluster/utils.go

@@ -17,6 +17,7 @@ package cluster
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"os"
 	"sort"
@@ -197,3 +198,23 @@ func getManagedAstarteResourceStatus(res unstructured.Unstructured) (string, tim
 
 	return operatorStatus, lastTransition, deploymentManager, deploymentProfile
 }
+
+func isUnstableVersion(version string) bool {
+	return strings.HasSuffix(version, "-snapshot") || version == "snapshot"
+}
+
+func getBaseVersionFromUnstable(version string) (string, error) {
+	if !isUnstableVersion(version) {
+		return "", fmt.Errorf("%v is not an unstable version", version)
+	}
+
+	if version == "snapshot" {
+		return "", errors.New("You are running on snapshot - I have no way of reconciling you from here")
+	}
+
+	// Get the base version, and add a .0.
+	baseVersion := strings.Replace(version, "-snapshot", "", 1)
+	baseVersion += ".0"
+
+	return baseVersion, nil
+}