Merge pull request #3 from ShaneMcC/check-for-cert

Check that certificate file exists before we create the service.

generate.py

 import etcdlib
 import jinja2
 import os
+import os.path
 
 parser = argparse.ArgumentParser()
 parser.add_argument('--name', help='Name of the docker host to request certificates for', default='unknown')
 fetcher = etcdlib.Connection(args.etcd_host, args.etcd_port, args.etcd_prefix)
 
 while True:
+  wroteConfig = False;
   services = []
   domains = {k: v.split(',') for k, v in fetcher.get_label('com.chameth.vhost').items()}
   protocols = fetcher.get_label('com.chameth.proxy.protocol')
   defaults = fetcher.get_label('com.chameth.proxy.default')
   for container, values in fetcher.get_label('com.chameth.proxy').items():
     networks = fetcher.get_networks(container)
-    services.append({
-      'protocol': protocols[container] if container in protocols else 'http',
-      'vhosts': domains[container],
-      'host': next(iter(networks.values())), # TODO: Pick a bridge sensibly?
-      'port': values,
-      'certificate': args.cert_path % domains[container][0],
-      'trusted_certificate': args.trusted_cert_path % domains[container][0],
-      'certificate_key': args.cert_key_path % domains[container][0],
-      'default': container in defaults,
-    })
-
-  with open('/nginx-config/vhosts.conf', 'w') as f:
-    print('Writing vhosts.conf...', flush=True)
-    f.write(template.render(services=services))
+    certfile = args.cert_path % domains[container][0];
+    if os.path.isfile(certfile):
+      services.append({
+        'protocol': protocols[container] if container in protocols else 'http',
+        'vhosts': domains[container],
+        'host': next(iter(networks.values())), # TODO: Pick a bridge sensibly?
+        'port': values,
+        'certificate': args.cert_path % domains[container][0],
+        'trusted_certificate': args.trusted_cert_path % domains[container][0],
+        'certificate_key': args.cert_key_path % domains[container][0],
+        'default': container in defaults,
+      })
+
+  if wroteConfig or len(services) > 0 or not os.path.isfile('/nginx-config/vhosts.conf'):
+    with open('/nginx-config/vhosts.conf', 'w') as f:
+      print('Writing vhosts.conf...', flush=True)
+      f.write(template.render(services=services))
+      wroteConfig = True;
+    print('Done writing config.', flush=True)
+  else:
+    print('Not writing empty config. Ensure that your letsencrypt certificates are accessible to this container.')
 
   print('Done writing config.', flush=True)