Added basic appliance config handling (specifically package installation and removal)

Also added unit tests for the above.

1 files changed, 61 insertions, 11 deletions

diff --git a/ec2-run-user-data.py b/ec2-run-user-data.py
index 51e0d68d..784a1b3f 100755
--- a/ec2-run-user-data.py
+++ b/ec2-run-user-data.py
@@ -22,20 +22,10 @@ import email
 import os
 import subprocess
 import tempfile
+from xml.dom.minidom import parse, parseString
 
 import ec2init
 
-content_type_handlers = { 'text/x-shellscript' : handle_shell_script,
-                          'text/x-ebs-mount-description' : handle_ebs_mount_description }
-
-def main():
-    ec2 = ec2init.EC2Init()
-
-    user_data = ec2.get_user_data()
-
-    msg = email.message_from_string(user_data)
-    handle_part(msg)
-
 def handle_part(part):
     if part.is_multipart():
         for p in part.get_payload():
@@ -51,6 +41,14 @@ def handle_unknown_payload(payload):
     # Try to detect magic
     if payload.startswith('#!'):
         content_type_handlers['text/x-shellscript'](payload)
+        return
+    if payload.startswith('<appliance>'):
+        content_type_handlers['text/x-appliance-config'](payload)
+
+
+def handle_appliance_config(payload):
+    app = ApplianceConfig(payload)
+    app.handle()
 
 def handle_ebs_mount_description(payload):
     (volume_description, path) = payload.split(':')
@@ -79,5 +77,57 @@ def handle_shell_script(payload):
     
     os.unlink(path)
 
+content_type_handlers = { 'text/x-shellscript' : handle_shell_script,
+                          'text/x-ebs-mount-description' : handle_ebs_mount_description,
+                          'text/x-appliance-config': handle_appliance_config }
+
+class ApplianceConfig(object):
+    def __init__(self, data):
+        self.data = data
+
+    def handle(self):
+        self.dom = parseString(self.data)
+
+        if self.dom.childNodes[0].tagName == 'appliance':
+            root = self.dom.childNodes[0]
+        else:
+            return
+
+        for node in root.childNodes:
+            if node.tagName == 'package':
+                pkg = None
+                for subnode in node.childNodes:
+                    if subnode.nodeType == root.TEXT_NODE:
+                        pkg = subnode.nodeValue
+                if not pkg:
+                    # Something's fishy. We should have been passed the name of
+                    # a package.
+                    return
+                if node.getAttribute('action') == 'remove':
+                    remove_package(pkg)
+                else:
+                    install_package(pkg)
+
+def main():
+    ec2 = ec2init.EC2Init()
+
+    user_data = ec2.get_user_data()
+    msg = parse_user_data(user_data)
+    handle_part(msg)
+
+def parse_user_data(user_data):
+    return email.message_from_string(user_data)
+
+def install_remove_package(pkg, action):
+    apt_get = subprocess.Popen(['apt-get', action, pkg], stdout=subprocess.PIPE)
+    logger_process = subprocess.Popen(['logger', '-t', 'user-data'], stdin=apt_get.stdout)
+    logger_process.communicate()
+
+def install_package(pkg):
+    return install_remove_package(pkg, 'install')
+
+def remove_package(pkg):
+    return install_remove_package(pkg, 'remove')
+
 if __name__ == '__main__':
     main()