Add UUID support for SYSLINUX

- refactoring
- code quality

.gitmodules

@@ -1,3 +1,3 @@
 [submodule "data"]
 	path = data
-	url = git@git.bitmessage.org:Bitmessage/cloud-init-cherrypy-data.git
+	url = git@git.bitmessage.org:Sysdeploy/cloud-init-cherrypy-data.git

main.py

@@ -7,12 +7,14 @@ import configparser
 import os
 import socket
 import sys
+import uuid as uuid_module
 from ipaddress import AddressValueError, IPv4Address, IPv6Address
+from os import access, R_OK
 
-import yaml
 import cherrypy
-from cherrypy.lib.static import serve_file
-
+# from cherrypy.lib.static import serve_file
+from jinja2 import Template
+import yaml
 
 PATH = os.path.dirname(os.path.abspath(__file__))
 
@@ -24,17 +26,34 @@ META_DATA_FILENAME = CONFIG["app"].get("meta_data", "meta-data")
 REDIRECT_FILENAME = CONFIG["app"].get("redirect", "redirect")
 
 
-class CloudInitApp:
+class CloudInitRequest:
     """
-    Serve cloud init files
+    Request data for persistence across methods
     """
-
-    def __init__(self):
+    def __init__(self, request, uuid=None):
         self.remoteip = None
         self.hostinfo = ('localhost', )
+        self.request = request
+        self.meta_data = None
+        self.meta_data_loaded = False
+        self.user_data = None
+
+        try:
+            self.uuid = str(uuid_module.UUID('{' + uuid + '}'))
+        # ValueError is wrong UUID syntax
+        # TypeError is None
+        except (ValueError, TypeError):
+            self.uuid = None
+
+        self._init_ip()
+        self._generate_default_meta_data()
 
     def _can_ip_be_proxy(self):
-        self.remoteip = cherrypy.request.remote.ip
+        """
+        Assuming the connection is through a proxy, is this proxy permitted?
+        Can't proxy from a publicly reachable IP.
+        """
+        self.remoteip = self.request.remote.ip
         try:
             ipobj = IPv4Address(self.remoteip)
         except AddressValueError:
@@ -50,90 +69,229 @@ class CloudInitApp:
         """
         if self._can_ip_be_proxy():
             try:
-                self.remoteip = cherrypy.request.headers.get(
+                self.remoteip = self.request.headers.get(
                     'X-Real-Ip',
-                    cherrypy.request.remote.ip
+                    self.request.remote.ip
                 )
             except KeyError:
                 pass
 
         try:
             self.hostinfo = socket.gethostbyaddr(self.remoteip)
+            forward_lookup = socket.gethostbyname(self.hostinfo[0])
+            if forward_lookup != self.remoteip:
+                self.hostinfo = ('localhost', )
         except socket.herror:
-            pass
+            self.hostinfo = ('localhost', )
+        except socket.gaierror:
+            self.hostinfo = (self.remoteip, )
 
-    def _redirect_if_needed(self):
-        filepath = os.path.join(PATH, "data", self.hostinfo[0],
-                                REDIRECT_FILENAME)
-        if os.path.exists(filepath):
+    def _generate_default_meta_data(self):
+        """
+        Build default meta-data based on the requesting IP
+        """
+        hostname = self.hostinfo[0]
+        base = self.request.base
+        self.meta_data = {
+            "instance-id": hostname.split(".")[0],
+            "local-hostname": hostname,
+            "baseurl": base
+        }
+
+    def _update_meta_data_from_file(self, filename):
+        """
+        Load meta-data from a file
+        """
+        with open(filename, "r") as metadata:
+            self.meta_data.update(yaml.safe_load(metadata))
+
+    def _get_filename(self, filetype):
+        """
+        Get the best available filename for a given type
+        """
+        check_dirs = ['localhost', ]
+        if self.uuid:
+            check_dirs.insert(0, self.uuid)
+        if self.meta_data['local-hostname'] != 'localhost':
+            check_dirs.insert(0, self.meta_data['local-hostname'])
+        for subdir in check_dirs:
+            filepath = os.path.join(PATH, "data",
+                                    subdir,
+                                    filetype)
+            if not os.path.isfile(filepath) \
+               or not access(filepath, R_OK):
+                continue
+            return filepath
+        return None
+
+    def get_meta_data(self):
+        """
+        Return the appropriate meta-data for this request
+        """
+        if self.meta_data_loaded:
+            return self.meta_data
+        self._generate_default_meta_data()
+        filename = self._get_filename(META_DATA_FILENAME)
+        if filename:
+            self._update_meta_data_from_file(
+                filename
+                )
+        self.meta_data_loaded = True
+        return self.meta_data
+
+    def save_meta_data(self, data):
+        """
+        Save metadata
+        """
+        filename = self._get_filename(META_DATA_FILENAME)
+        with open(filename, "wt") as filehandle:
+            filehandle.write(data)
+
+    def get_user_data(self):
+        """
+        Return the appropriate meta-data for this request
+        """
+        if self.user_data:
+            return self.user_data
+        filename = self._get_filename(USER_DATA_FILENAME)
+        if not filename:
+            return None
+        with open(filename, "r") as userdata:
+            self.user_data = userdata.read()
+            return self.user_data
+        return None
+
+    def optional_redirect(self):
+        """
+        Return optional redirect, or None
+        """
+        filename = self._get_filename(REDIRECT_FILENAME)
+        if not (filename and os.path.exists(filename)):
+            return None
         try:
-                with open(filepath) as redirect:
+            with open(filename) as redirect:
                 content = redirect.read().splitlines()
-                raise cherrypy.HTTPRedirect(content[0], 301)
+                return content[0]
         except IOError:
-                return False
+            return None
+        return None
+
+
+class CloudInitApp:
+    """
+    Serve cloud init files
+    """
+
+    @staticmethod
+    def _redirect_if_needed(request):
+        redirect = request.optional_redirect()
+        if redirect:
+            raise cherrypy.HTTPRedirect(redirect, 301)
         return False
 
-    @cherrypy.expose
-    def user_data(self):
+    @staticmethod
+    def _content_type(data):
+        if not data:
+            return "text/cloud-config"
+        if data.startswith("#include"):
+            return "text/x-include-url"
+        if data.startswith("## template: jinja"):
+            return "text/jinja2"
+        return "text/cloud-config"
+
+    @staticmethod
+    def _wrap_metadata(metadata):
+        return {'ds': {
+            'meta_data': metadata
+            }}
+
+    def _user_data(self, uuid=None, SYSUUID=None):
         """
         Serves a static file
+        But can process a template if x-include-url
         """
-        self._init_ip()
-        self._redirect_if_needed()
-        filepath = os.path.join(PATH, "data", self.hostinfo[0],
-                                USER_DATA_FILENAME)
-        if not os.path.exists(filepath):
-            filepath = os.path.join(PATH, "data", USER_DATA_FILENAME)
-        return serve_file(filepath, "text/yaml", "attachment")
+        if SYSUUID:  # SYSLINUX support
+            uuid = SYSUUID
+        request = CloudInitRequest(cherrypy.request, uuid)
+        self._redirect_if_needed(request)
+        user_data = request.get_user_data()
 
-    @cherrypy.expose
-    def meta_data(self):
+        c__ = self._content_type(user_data)
+
+        cherrypy.response.headers['Content-Type'] = c__
+        cherrypy.response.headers['Content-Disposition'] = \
+            'attachment; filename="user-data"'
+
+        if c__ == "text/x-include-url":
+            t__ = Template(user_data)
+            metadata = request.get_meta_data()
+            wrapped = CloudInitApp._wrap_metadata(metadata)
+            return t__.render(**wrapped)
+        return user_data
+
+    def _meta_data(self, uuid=None):
         """
         Return meta-data in YAML
         """
-        self._init_ip()
-        self._redirect_if_needed()
-        hostname = self.hostinfo[0]
-        data = {
-            "instance-id": hostname.split(".")[0],
-            "local-hostname": hostname
-        }
-
-        filepath = os.path.join(PATH, "data", hostname, META_DATA_FILENAME)
-        if os.path.exists(filepath):
-            with open(filepath, "r") as metadata:
-                for line in metadata.readlines():
-                    linesplit = list(map(lambda k: k.strip(), line.split(":")))
-                    data[linesplit[0]] = linesplit[1]
+        request = CloudInitRequest(cherrypy.request, uuid)
+        self._redirect_if_needed(request)
 
         cherrypy.response.headers['Content-Type'] = \
             'text/yaml'
         cherrypy.response.headers['Content-Disposition'] = \
-            'attachment; filename="user-data"'
-        return yaml.dump(data)
+            'attachment; filename="meta-data"'
+        return yaml.dump(request.get_meta_data())
+
+    @staticmethod
+    def _vendor_data():
+        return ""
+
+    @cherrypy.expose
+    def user_data(self):
+        """
+        v1 api endpoint user-data
+        """
+        return self._user_data()
+
+    @cherrypy.expose
+    def meta_data(self):
+        """
+        v1 api endpoint meta-data
+        """
+        return self._meta_data()
 
     @cherrypy.expose
     def vendor_data(self):
         """
-        Return empty vendor-data
+        v1 api endpoint vendor-data
         """
-        return ""
+        return self._vendor_data()
 
     @cherrypy.expose
+    def apiv2(self, uuid=None, filetype="user-data"):
+        """
+        API endpoint v2
+        extract command from arguments
+        """
+        if filetype == "user-data":
+            return self._user_data(uuid)
+        if filetype == "meta-data":
+            return self._meta_data(uuid)
+        if filetype == "vendor-data":
+            return self._vendor_data()
+        return ""
+
+    # unused
+    # @cherrypy.expose
     def finished(self, data):
         """
         Saves additional meta-data
 
         :param data: meta-data to be added
         """
-        self._init_ip()
-        folder = os.path.join(PATH, "data", self.hostinfo[0])
-        if not os.path.exists(folder):
-            os.makedirs(folder)
-
-        with open(os.path.join(folder, META_DATA_FILENAME), "w") as fin:
-            fin.write(data)
+        request = CloudInitRequest(cherrypy.request)
+        self._redirect_if_needed(request)
+        request.save_meta_data(data)
 
 
 ROOT = CloudInitApp()
@@ -145,14 +303,27 @@ if __name__ == "__main__":
         CONFIG["server"].getint("server_port", 8081)
     ENGINE = cherrypy.engine
 
-    cherrypy.tree.mount(ROOT)
+    CURRENT_DIR = os.path.dirname(os.path.abspath(__file__))
+    CONFIG = {
+        '/include': {
+            'tools.staticdir.on': True,
+            'tools.staticdir.dir': os.path.join(CURRENT_DIR,
+                                                'data',
+                                                'include'),
+            'tools.staticdir.content_types': {
+                'yml': 'text/yaml'
+                }
+            }
+        }
+    cherrypy.tree.mount(ROOT, config=CONFIG)
+
     if hasattr(ENGINE, "signal_handler"):
         ENGINE.signal_handler.subscribe()
     if hasattr(ENGINE, "console_control_handler"):
         ENGINE.console_control_handler.subscribe()
     try:
         ENGINE.start()
-    except Exception:
+    except Exception:  # pylint: disable=broad-except
         sys.exit(1)
     else:
         ENGINE.block()