ore/aws/delete-image: Handle missing SnapshotID

Added a check for when the snapshotID is None by giving it the value
of detectFromAMI. Then we aim to determine the snapshot by seeing if
we have any associated with the AMI-ID. If nothing shows up, we define
it as pruned

mantle/cmd/ore/aws/delete-image.go

@@ -57,6 +57,18 @@ func runDeleteImage(cmd *cobra.Command, args []string) {
 	}
 
 	if snapshotID != "" {
+		if snapshotID == "detectFromAMI" && amiID != "" {
+			// Let's try to extract the snapshotID from AMI
+			snapshot, err := API.FindSnapshot(amiID)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "Warning: Encountered error when searching for snapshot for %s: %s. Continuing..\n", amiID, err)
+				os.Exit(0)
+			} else if snapshot == nil {
+				fmt.Fprintf(os.Stdout, "No valid snapshot found for %s.\n", amiID)
+				os.Exit(0)
+			}
+			snapshotID = snapshot.SnapshotID
+		}
 		err := API.RemoveBySnapshotTag(snapshotID, allowMissing)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "Could not delete %v: %v\n", snapshotID, err)

src/cmd-cloud-prune

@@ -324,7 +324,9 @@ def deregister_aws_amis(build, cloud_config, dry_run):
     for ami in amis:
         region_name = ami.get("name")
         ami_id = ami.get("hvm")
-        snapshot_id = ami.get("snapshot")
+        # If we are dealing with an old manifest where the snapshot ID isn't stored
+        # then let's instruct ore to detect the snapshot ID from the AMI.
+        snapshot_id = ami.get("snapshot", "detectFromAMI")
         if dry_run:
             print(f"Would delete {ami_id} and {snapshot_id} for {build.id}")
             continue