add 'bootcmd' like 'runcmd' to cloud-config syntax for running things early

ChangeLog

@@ -14,6 +14,8 @@
    the /var/lib/cloud/instance/ link, for a data source that might
    not be present on every boot
  - make DataSourceEc2 retries and timeout configurable
+ - add helper routines for apt-get update and install
+ - add 'bootcmd' like 'runcmd' to cloud-config syntax for running things early
 0.6.0:
  - change permissions of /var/log/cloud-init.log to accomodate
    syslog writing to it (LP: #704509)

cloudinit/CloudConfig/cc_bootcmd.py

@@ -0,0 +1,40 @@
+# vi: ts=4 expandtab
+#
+#    Copyright (C) 2009-2011 Canonical Ltd.
+#
+#    Author: Scott Moser <scott.moser@canonical.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/>.
+import cloudinit.util as util
+import subprocess
+import tempfile
+
+def handle(name,cfg,cloud,log,args):
+    if not cfg.has_key("bootcmd"):
+        return
+
+    try:
+        content = util.shellify(cfg["bootcmd"])
+        tmpf = tempfile.TemporaryFile()
+        tmpf.write(content)
+        tmpf.seek(0)
+    except:
+        log.warn("failed to shellify bootcmd")
+        raise
+    
+    try:
+        subprocess.check_call(['/bin/sh'], stdin=tmpf)
+        tmpf.close()
+    except:
+        log.warn("failed to run commands from bootcmd")
+        raise

cloudinit/CloudConfig/cc_runcmd.py

@@ -22,21 +22,8 @@ def handle(name,cfg,cloud,log,args):
     if not cfg.has_key("runcmd"):
         return
     outfile="%s/runcmd" % cloud.get_ipath('scripts')
-
-    content="#!/bin/sh\n"
-    escaped="%s%s%s%s" % ( "'", '\\', "'", "'" )
     try:
-        for args in cfg["runcmd"]:
-            # if the item is a list, wrap all items in single tick
-            # if its not, then just write it directly
-            if isinstance(args,list):
-                fixed = [ ]
-                for f in args:
-                    fixed.append("'%s'" % str(f).replace("'",escaped))
-                content="%s%s\n" % ( content, ' '.join(fixed) )
-            else:
-                content="%s%s\n" % ( content, str(args) )
-
+        content = util.shellify(cfg["runcmd"])
         util.write_file(outfile,content,0700)
     except:
         log.warn("failed to open %s for runcmd" % outfile)

cloudinit/util.py

@@ -338,3 +338,22 @@ def readurl(url, data=None):
 
    response = urllib2.urlopen(req)
    return(response.read())
+
+# shellify, takes a list of commands
+#  for each entry in the list
+#    if it is an array, shell protect it (with single ticks)
+#    if it is a string, do nothing
+def shellify(cmdlist):
+    content="#!/bin/sh\n"
+    escaped="%s%s%s%s" % ( "'", '\\', "'", "'" )
+    for args in cmdlist:
+        # if the item is a list, wrap all items in single tick
+        # if its not, then just write it directly
+        if isinstance(args,list):
+            fixed = [ ]
+            for f in args:
+                fixed.append("'%s'" % str(f).replace("'",escaped))
+            content="%s%s\n" % ( content, ' '.join(fixed) )
+        else:
+            content="%s%s\n" % ( content, str(args) )
+    return content

config/cloud.cfg

@@ -4,6 +4,7 @@ preserve_hostname: False
 # datasource_list: [ "NoCloud", "OVF", "Ec2" ]
 
 cloud_init_modules:
+ - bootcmd
  - resizefs
  - set_hostname
  - update_hostname

doc/examples/cloud-config.txt

@@ -190,6 +190,16 @@ runcmd:
  - [ wget, "http://slashdot.org", -O, /tmp/index.html ]
 
 
+# boot commands
+# default: none
+# this is very similar to runcmd above, but commands run very early
+# in the boot process, only slightly after a 'boothook' would run.
+# bootcmd should really only be used for things that could not be
+# done later in the boot process.  bootcmd is very much like
+# boothook, but possibly with more friendly
+bootcmd:
+ - echo 192.168.1.130 us.archive.ubuntu.com > /etc/hosts
+
 # cloud_config_modules:
 # default:
 # cloud_config_modules: