move writing sources.list to CloudConfig. add 'apt_preserve_sources_list'

Move the writing of sources.list to CloudConfig.  This way we have
access to the cloud-config user data.  Then, allow the user
to specify the archive mirror using 'apt_mirror' key. 

Now, if specified in cloud-config, that is used, otherwise, we 
get one from the DataSource.

One other change here is adding 'apt_preserve_sources_list'.  If set to
true, then overwriting of the sources.list with the selected mirror
will not be done.

ec2-init.py

@@ -1,10 +1,10 @@
 #!/usr/bin/python
 
 import subprocess
-from Cheetah.Template import Template
 import sys
 
 import ec2init
+import ec2init.util as util
 
 def warn(str):
     sys.stderr.write(str)
@@ -56,27 +56,15 @@ def main():
 
     sys.exit(0)
 
-def render_to_file(template, outfile, searchList):
-    t = Template(file='/etc/ec2-init/templates/%s.tmpl' % template, searchList=[searchList])
-    f = open(outfile, 'w')
-    f.write(t.respond())
-    f.close()
-
 def set_defaults(cloud):
-    generate_sources_list(cloud.get_mirror())
     apply_locale(cloud.get_locale())
     
 def apply_locale(locale):
     subprocess.Popen(['locale-gen', locale]).communicate()
     subprocess.Popen(['update-locale', locale]).communicate()
 
-    render_to_file('default-locale', '/etc/default/locale', { 'locale' : locale })
+    util.render_to_file('default-locale', '/etc/default/locale', \
-
+        { 'locale' : locale })
-def generate_sources_list(mirror):
-    stdout, stderr = subprocess.Popen(['lsb_release', '-cs'], stdout=subprocess.PIPE).communicate()
-    codename = stdout.strip()
-
-    render_to_file('sources.list', '/etc/apt/sources.list', { 'mirror' : mirror, 'codename' : codename })
 
 if __name__ == '__main__':
     main()

ec2init/CloudConfig.py

@@ -99,6 +99,13 @@ class CloudConfig():
         update = util.get_cfg_option_bool(self.cfg, 'apt_update', False)
         upgrade = util.get_cfg_option_bool(self.cfg, 'apt_upgrade', False)
 
+        if not util.get_cfg_option_bool(self.cfg, \
+            'apt_preserve_sources_list', False):
+            if self.cfg.has_key("apt_mirror"):
+                mirror = self.cfg["apt_mirror"]
+            else:
+                mirror = self.cloud.get_mirror()
+            generate_sources_list(mirror)
 
         # process 'apt_sources'
         if self.cfg.has_key('apt_sources'):
@@ -277,3 +284,11 @@ def add_sources(srclist):
             elst.append([source, "failed write to file %s" % ent['filename']])
 
     return(elst)
+
+
+def generate_sources_list(mirror):
+    stdout, stderr = subprocess.Popen(['lsb_release', '-cs'], stdout=subprocess.PIPE).communicate()
+    codename = stdout.strip()
+
+    util.render_to_file('sources.list', '/etc/apt/sources.list', \
+        { 'mirror' : mirror, 'codename' : codename })

ec2init/__init__.py

@@ -260,6 +260,15 @@ class EC2Init:
             f=open(cloud_config, "wb")
             f.write(self.cloud_config_str)
             f.close()
+
+            ## this could merge the cloud config with the system config
+            ## for now, not doing this as it seems somewhat circular
+            ## as CloudConfig does that also, merging it with this cfg
+            ##
+            # ccfg = yaml.load(self.cloud_config_str)
+            # if ccfg is None: ccfg = { }
+            # self.cfg = util.mergedict(ccfg, self.cfg)
+
             return
 
         self.cloud_config_str+="\n#%s\n%s" % (filename,payload)

ec2init/util.py

@@ -2,6 +2,7 @@ import yaml
 import os
 import errno
 import subprocess
+from Cheetah.Template import Template
 
 def read_conf(fname):
 	stream = file(fname)
@@ -69,3 +70,10 @@ def subp(args, input=None):
     if sp.returncode is not 0:
         raise subprocess.CalledProcessError(sp.returncode,args)
     return(out,err)
+
+def render_to_file(template, outfile, searchList):
+    t = Template(file='/etc/ec2-init/templates/%s.tmpl' % template, searchList=[searchList])
+    f = open(outfile, 'w')
+    f.write(t.respond())
+    f.close()
+