cc_landscape & cc_puppet: Fix six.StringIO use in writing configs

Both landscape and puppet modules had issues with the way they wrote
/etc/landscape/client.conf or /etc/puppet/puppet.conf in either python3 or
python2. This branch adds initial unit tests for both modules which will
get better exercise under both python2 and python3.

The unit tests shed light on a few issues:
   - In the cc_landscape module py3 can't provide six.StringIO content to
     ConfigParser.write, so we need to use six.BytesIO instead
   - In the cc_puppet module, python <= 2.7 doesn't support using
     six.StringIO as a context manager, so we drop the context manager
     fanciness and directly set outputstream = StringIO().
   - The docstring in cc_puppet is fixed to document the 'conf'
     sub-key requiring valid puppet section names for each
     key-value list.

LP: #1699282
LP: #1710932

3 files changed, 27 insertions, 24 deletions

diff --git a/cloudinit/config/cc_landscape.py b/cloudinit/config/cc_landscape.py
index 86b71383..8f9f1abd 100644
--- a/cloudinit/config/cc_landscape.py
+++ b/cloudinit/config/cc_landscape.py
@@ -57,7 +57,7 @@ The following default client config is provided, but can be overridden::
 
 import os
 
-from six import StringIO
+from six import BytesIO
 
 from configobj import ConfigObj
 
@@ -109,7 +109,7 @@ def handle(_name, cfg, cloud, log, _args):
         ls_cloudcfg,
     ]
     merged = merge_together(merge_data)
-    contents = StringIO()
+    contents = BytesIO()
     merged.write(contents)
 
     util.ensure_dir(os.path.dirname(LSC_CLIENT_CFG_FILE))
diff --git a/cloudinit/config/cc_puppet.py b/cloudinit/config/cc_puppet.py
index dc11561b..28b1d568 100644
--- a/cloudinit/config/cc_puppet.py
+++ b/cloudinit/config/cc_puppet.py
@@ -15,21 +15,23 @@ This module handles puppet installation and configuration. If the ``puppet``
 key does not exist in global configuration, no action will be taken. If a
 config entry for ``puppet`` is present, then by default the latest version of
 puppet will be installed. If ``install`` is set to ``false``, puppet will not
-be installed. However, this may result in an error if puppet is not already
+be installed. However, this will result in an error if puppet is not already
 present on the system. The version of puppet to be installed can be specified
 under ``version``, and defaults to ``none``, which selects the latest version
 in the repos. If the ``puppet`` config key exists in the config archive, this
 module will attempt to start puppet even if no installation was performed.
 
-Puppet configuration can be specified under the ``conf`` key. The configuration
-is specified as a dictionary which is converted into ``<key>=<value>`` format
-and appended to ``puppet.conf`` under the ``[puppetd]`` section. The
+Puppet configuration can be specified under the ``conf`` key. The
+configuration is specified as a dictionary containing high-level ``<section>``
+keys and lists of ``<key>=<value>`` pairs within each section. Each section
+name and ``<key>=<value>`` pair is written directly to ``puppet.conf``. As
+such,  section names should be one of: ``main``, ``master``, ``agent`` or
+``user`` and keys should be valid puppet configuration options. The
 ``certname`` key supports string substitutions for ``%i`` and ``%f``,
 corresponding to the instance id and fqdn of the machine respectively.
-If ``ca_cert`` is present under ``conf``, it will not be written to
-``puppet.conf``, but instead will be used as the puppermaster certificate.
-It should be specified in pem format as a multi-line string (using the ``|``
-yaml notation).
+If ``ca_cert`` is present, it will not be written to ``puppet.conf``, but
+instead will be used as the puppermaster certificate. It should be specified
+in pem format as a multi-line string (using the ``|`` yaml notation).
 
 **Internal name:** ``cc_puppet``
 
@@ -43,12 +45,13 @@ yaml notation).
         install: <true/false>
         version: <version>
         conf:
-            server: "puppetmaster.example.org"
-            certname: "%i.%f"
-            ca_cert: |
-                -------BEGIN CERTIFICATE-------
-                <cert data>
-                -------END CERTIFICATE-------
+            agent:
+                server: "puppetmaster.example.org"
+                certname: "%i.%f"
+                ca_cert: |
+                    -------BEGIN CERTIFICATE-------
+                    <cert data>
+                    -------END CERTIFICATE-------
 """
 
 from six import StringIO
@@ -127,7 +130,7 @@ def handle(name, cfg, cloud, log, _args):
                 util.write_file(PUPPET_SSL_CERT_PATH, cfg)
                 util.chownbyname(PUPPET_SSL_CERT_PATH, 'puppet', 'root')
             else:
-                # Iterate throug the config items, we'll use ConfigParser.set
+                # Iterate through the config items, we'll use ConfigParser.set
                 # to overwrite or create new items as needed
                 for (o, v) in cfg.items():
                     if o == 'certname':
diff --git a/cloudinit/helpers.py b/cloudinit/helpers.py
index f01021aa..1979cd96 100644
--- a/cloudinit/helpers.py
+++ b/cloudinit/helpers.py
@@ -13,7 +13,7 @@ from time import time
 import contextlib
 import os
 
-import six
+from six import StringIO
 from six.moves.configparser import (
     NoSectionError, NoOptionError, RawConfigParser)
 
@@ -441,12 +441,12 @@ class DefaultingConfigParser(RawConfigParser):
 
     def stringify(self, header=None):
         contents = ''
-        with six.StringIO() as outputstream:
-            self.write(outputstream)
-            outputstream.flush()
-            contents = outputstream.getvalue()
-            if header:
-                contents = "\n".join([header, contents])
+        outputstream = StringIO()
+        self.write(outputstream)
+        outputstream.flush()
+        contents = outputstream.getvalue()
+        if header:
+            contents = '\n'.join([header, contents, ''])
         return contents
 
 # vi: ts=4 expandtab