Add Docker runtime helper and explicitly labelled service inventory

docker_support.py

@@ -0,0 +1,22 @@
+"""Narrow client: the web app never receives Docker's daemon socket."""
+import json
+import os
+import socket
+
+MANAGED_LABEL='io.athena-deck.managed=true'
+ROLE_LABEL='io.athena-deck.role=application'
+
+class DockerSupport:
+ def call(self,action):
+  path=os.environ.get('DECK_DOCKER_HELPER_SOCKET','/run/athena-deck-docker/control.sock')
+  with socket.socket(socket.AF_UNIX) as sock:
+   sock.settimeout(20);sock.connect(path);sock.sendall(json.dumps({'action':action}).encode()+b'\n')
+   with sock.makefile('rb') as stream:raw=stream.readline(1048577)
+  if len(raw)>1048576:raise ValueError('Docker-Helferantwort zu groß.')
+  value=json.loads(raw)
+  if 'error' in value:raise ValueError(value['error'])
+  return value
+ def status(self):
+  try:return dict(self.call('status'),helper_available=True)
+  except (OSError,ValueError):return dict(helper_available=False,installed=None,reachable=False,services=[],install_supported=False,job=None,message='Docker-Systemhelfer nicht verbunden. Der Deck-Installer muss ihn auf dem Debian-Host einrichten.',labels=[MANAGED_LABEL,ROLE_LABEL])
+ def install(self):return self.call('install')