Attach a label to servers with their desired deletion date

This then enables us to periodically scan for images with a unix
timestamp in the label that's smaller than now() and delete them.

Co-authored-by: Ewoud Kohl van Wijngaarden <ewoud@kohlvanwijngaarden.nl>

README.md

@@ -44,9 +44,19 @@ are being created:
 
 # Cleanup
 
-In cases where the beaker process is killed before finishing, it may leave resources in Hetzner cloud. These will need to be manually deleted.
+Every created cloud instance gets a label `delete_vm_after: 1698792887`. By
+default this is the UNIX timestamp during VM creation + an hour.
 
-Look for servers in your project named exactly as the ones in your beaker host configuration and SSH keys with names beginning with `Beaker-`.
+You can modify the default of an hour by setting the `BEAKER_HCLOUD_DELETE_VM_AFTER`
+environment variable to any positive integer. It will be interpreted as seconds.
+
+In cases where the beaker process is killed before finishing, it may leave
+resources in Hetzner cloud. These will need to be manually deleted. Look for
+servers in your project named exactly as the ones in your beaker host
+configuration and SSH keys with names beginning with `Beaker-`.
+
+You can also periodically scan for VMs where the `delete_vm_after` points to a
+past timestamp and delete them.
 
 # Contributing
 

lib/beaker/hypervisor/hcloud.rb

@@ -3,6 +3,7 @@
 require 'hcloud'
 require 'ed25519'
 require 'bcrypt_pbkdf'
+require 'time'
 
 require_relative '../../beaker-hcloud/ssh_data_patches'
 
@@ -15,7 +16,9 @@ def initialize(hosts, options) # rubocop:disable Lint/MissingSuper
       @options = options
       @logger = options[:logger] || Beaker::Logger.new
       @hosts = hosts
+      @delete_vm_after = ENV.fetch('BEAKER_HCLOUD_DELETE_VM_AFTER', 60 * 60).to_i
 
+      raise 'BEAKER_HCLOUD_DELETE_VM_AFTER needs to be a positive integer' unless @delete_vm_after.positive?
       raise 'You need to pass a token as BEAKER_HCLOUD_TOKEN environment variable' unless ENV['BEAKER_HCLOUD_TOKEN']
 
       @client = ::Hcloud::Client.new(token: ENV.fetch('BEAKER_HCLOUD_TOKEN'))
@@ -53,6 +56,8 @@ def ssh_key_name
         @options[:aws_keyname_modifier],
         @options[:timestamp].strftime('%F_%H_%M_%S_%N'),
       ].join('-')
+      @logger.debug("ssh_key_name is: #{safe_hostname}")
+      safe_hostname
     end
 
     def create_ssh_key
@@ -69,6 +74,15 @@ def create_ssh_key
       hcloud_ssh_key
     end
 
+    # we need to save the date as unix timestamp. Hetzner Cloud labels only support:
+    # "alphanumeric character ([a-z0-9A-Z]) with dashes (-), underscores (_), dots (.), and alphanumerics between."
+    # https://docs.hetzner.cloud/#labels
+    def vm_deletion_date
+      date = (Time.now.to_i + @delete_vm_after).to_s
+      @logger.debug("Server is valid until: #{date}")
+      date
+    end
+
     def create_server(host)
       @logger.notify "provisioning #{host.name}"
       location = host[:location] || 'nbg1'
@@ -79,6 +93,7 @@ def create_server(host)
         server_type: server_type,
         image: host[:image],
         ssh_keys: [ssh_key_name],
+        labels: { delete_vm_after: vm_deletion_date },
       )
       while action.status == 'running'
         sleep 5

spec/beaker/hypervisor/hcloud_spec.rb

@@ -45,7 +45,8 @@
                'dns_ptr' => 'server1.example.com',
              },
            },
-           destroy: true)
+           destroy: true,
+           labels: { vm_delete_after: '1695385549' })
   end
   let(:server2) do
     double(:server2,
@@ -56,7 +57,8 @@
                'dns_ptr' => 'server2.example.com',
              },
            },
-           destroy: true)
+           destroy: true,
+           labels: { vm_delete_after: '1695385549' })
   end
   let(:action_double) do
     double(:action, status: 'success')