Added new feature include-once

3 files changed, 36 insertions, 2 deletions

diff --git a/cloudinit/UserDataHandler.py b/cloudinit/UserDataHandler.py
index 83377dab..4fd6ef28 100644
--- a/cloudinit/UserDataHandler.py
+++ b/cloudinit/UserDataHandler.py
@@ -25,6 +25,7 @@ import yaml
 
 starts_with_mappings={
     '#include' : 'text/x-include-url',
+    '#include-once' : 'text/x-include-once-url',
     '#!' : 'text/x-shellscript',
     '#cloud-config' : 'text/cloud-config',
     '#upstart-job'  : 'text/upstart-job',
@@ -45,16 +46,34 @@ def decomp_str(str):
 
 def do_include(str,parts):
     import urllib
+    import os
+    import base64
     # is just a list of urls, one per line
     # also support '#include <url here>'
+    includeonce = False
     for line in str.splitlines():
         if line == "#include": continue
-        if line.startswith("#include"):
+        if line == "#include-once":
+            includeonce == True
+        if line.startswith("#include-once"):
+            line = line[len("#include-once"):].lstrip()
+            includeonce = True
+        elif line.startswith("#include"):
             line = line[len("#include"):].lstrip()
         if line.startswith("#"): continue
-        content = urllib.urlopen(line).read()
+        if includeonce == True:
+            uniquestring = base64.encodestring(line).strip('\n')
+            includeonce_filename = "/var/lib/cloud/instance/.includeonce.%s" % uniquestring
+            if os.path.isfile(includeonce_filename): continue
+            includeonce_file = open(includeonce_filename,'w')
+            includeonce_file.close()
+        try:
+            content = urllib.urlopen(line).read()
+        except Exception as e:
+            log.debug(traceback.format_exc(e))
         process_includes(email.message_from_string(decomp_str(content)),parts)
 
+
 def explode_cc_archive(archive,parts):
     for ent in yaml.load(archive):
         # ent can be one of:
diff --git a/doc/examples/include-once.txt b/doc/examples/include-once.txt
new file mode 100644
index 00000000..0cf74e5e
--- /dev/null
+++ b/doc/examples/include-once.txt
@@ -0,0 +1,7 @@
+#include-once
+# entries are one url per line. comment lines beginning with '#' are allowed
+# urls are passed to urllib.urlopen, so the format must be supported there
+# This entries will just be processed ONE TIME by cloud-init, any further
+# iterations won't process this file
+http://www.ubuntu.com/robots.txt
+http://www.w3schools.com/html/lastpage.htm
diff --git a/doc/userdata.txt b/doc/userdata.txt
index 00c16b25..3af1e632 100644
--- a/doc/userdata.txt
+++ b/doc/userdata.txt
@@ -36,6 +36,14 @@ finds.  However, certain types of user-data are handled specially.
    will be passed through this same set of rules.  Ie, the content
    read from the URL can be gzipped, mime-multi-part, or plain text
 
+* Include File Once
+   begins with  #include-once      or Content-Type: text/x-include-once-url
+   This content is a "include" file.  The file contains a list of
+   urls, one per line.  Each of the URLs will be read, and their content
+   will be passed through this same set of rules.  Ie, the content
+   read from the URL can be gzipped, mime-multi-part, or plain text
+   This file will just be processed once by cloud-init
+
  * Cloud Config Data
    begins with  #cloud-config or Content-Type: text/cloud-config