Added header and footer to generated Dockerfile.

platypush/platydock/__init__.py

@@ -36,6 +36,31 @@ class DockerfileGenerator:
         BaseImage.UBUNTU: PackageManagers.APT,
     }
 
+    _header = textwrap.dedent(
+        """
+        # This Dockerfile was automatically generated by Platydock.
+        #
+        # You can build a Platypush image from it by running
+        # `docker build -t platypush .` in the same folder as this file,
+        # or copy it to the root a Platypush source folder to install the
+        # checked out version instead of downloading it first.
+        #
+        # You can then run your new image through:
+        #   docker run --rm --name platypush \\
+        #       -v /path/to/your/config/dir:/etc/platypush \\
+        #       -v /path/to/your/workdir:/var/lib/platypush \\
+        #       -p 8080:8080 \\
+        #       platypush\n
+        """
+    )
+
+    _footer = textwrap.dedent(
+        """
+        # You can customize the name of your installation by passing
+        # --device-id=... to the launched command.
+        """
+    )
+
     def __init__(self, cfgfile: str, image: BaseImage, gitref: str) -> None:
         self.cfgfile = os.path.abspath(os.path.expanduser(cfgfile))
         self.image = image
@@ -72,6 +97,8 @@ class DockerfileGenerator:
         with open(base_file, 'r') as f:
             file_lines = [line.rstrip() for line in f.readlines()]
 
+        new_file_lines.extend(self._header.split('\n'))
+
         for line in file_lines:
             if re.match(
                 r'RUN /install/platypush/install/scripts/[A-Za-z0-9_-]+/install.sh',
@@ -96,6 +123,8 @@ class DockerfileGenerator:
                     is_after_expose_cmd = True
 
                 continue
+            elif line.startswith('CMD'):
+                new_file_lines.extend(self._footer.split('\n'))
 
             new_file_lines.append(line)