Add CloudSigma data source

1 files changed, 99 insertions, 0 deletions

diff --git a/cloudinit/cs_utils.py b/cloudinit/cs_utils.py
new file mode 100644
index 00000000..4e53c31a
--- /dev/null
+++ b/cloudinit/cs_utils.py
@@ -0,0 +1,99 @@
+# vi: ts=4 expandtab
+#
+#    Copyright (C) 2014 CloudSigma
+#
+#    Author: Kiril Vladimiroff <kiril.vladimiroff@cloudsigma.com>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License version 3, as
+#    published by the Free Software Foundation.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+cepko implements easy-to-use communication with CloudSigma's VMs through
+a virtual serial port without bothering with formatting the messages
+properly nor parsing the output with the specific and sometimes
+confusing shell tools for that purpose.
+
+Having the server definition accessible by the VM can ve useful in various
+ways. For example it is possible to easily determine from within the VM,
+which network interfaces are connected to public and which to private network.
+Another use is to pass some data to initial VM setup scripts, like setting the
+hostname to the VM name or passing ssh public keys through server meta.
+
+For more information take a look at the Server Context section of CloudSigma
+API Docs: http://cloudsigma-docs.readthedocs.org/en/latest/server_context.html
+"""
+import json
+import platform
+
+import serial
+
+SERIAL_PORT = '/dev/ttyS1'
+if platform.system() == 'Windows':
+    SERIAL_PORT = 'COM2'
+
+
+class Cepko(object):
+    """
+    One instance of that object could be use for one or more
+    queries to the serial port.
+    """
+    request_pattern = "<\n{}\n>"
+
+    def get(self, key="", request_pattern=None):
+        if request_pattern is None:
+            request_pattern = self.request_pattern
+        return CepkoResult(request_pattern.format(key))
+
+    def all(self):
+        return self.get()
+
+    def meta(self, key=""):
+        request_pattern = self.request_pattern.format("/meta/{}")
+        return self.get(key, request_pattern)
+
+    def global_context(self, key=""):
+        request_pattern = self.request_pattern.format("/global_context/{}")
+        return self.get(key, request_pattern)
+
+
+class CepkoResult(object):
+    """
+    CepkoResult executes the request to the virtual serial port as soon
+    as the instance is initialized and stores the result in both raw and
+    marshalled format.
+    """
+    def __init__(self, request):
+        self.request = request
+        self.raw_result = self._execute()
+        self.result = self._marshal(self.raw_result)
+
+    def _execute(self):
+        connection = serial.Serial(SERIAL_PORT)
+        connection.write(self.request)
+        return connection.readline().strip('\x04\n')
+
+    def _marshal(self, raw_result):
+        try:
+            return json.loads(raw_result)
+        except ValueError:
+            return raw_result
+
+    def __len__(self):
+        return self.result.__len__()
+
+    def __getitem__(self, key):
+        return self.result.__getitem__(key)
+
+    def __contains__(self, item):
+        return self.result.__contains__(item)
+
+    def __iter__(self):
+        return self.result.__iter__()