Better support for running Plone on PaaS providers such as Heroku

CHANGES.rst

@@ -10,7 +10,11 @@ Breaking changes:
 
 New features:
 
-- *add item here*
+- Added support for setting `instance-home` option.
+  [zupo]
+
+- Added support for setting CGI environment variables.
+  [zupo]
 
 Bug fixes:
 

README.rst

@@ -74,6 +74,13 @@ environment-vars
       zope_i18n_allowed_languages en
       zope_i18n_compile_mo_files true
 
+cgi-environment-vars
+  Define arbitrary key-value pairs for use as CGI environment variables during
+  Zope's run cycle. Example::
+
+    cgi-environment-vars =
+      HTTPS ON
+
 initialization
    Specify some Python initialization code to include within the generated
    ``sitecustomize.py`` script (Buildout >= 1.5) or within the instance script
@@ -341,6 +348,10 @@ before-storage
   normally running site in order for changes to be made to the
   database.
 
+instance-home
+  Sets the instancehome for the generated instance.
+  Defaults to ${buildout:directory}/parts/<name of the section>.
+
 client-home
   Sets the clienthome for the generated instance.
   Defaults to ${buildout:directory}/var/<name of the section>.

src/plone/recipe/zope2instance/__init__.py

@@ -40,6 +40,24 @@ def indent(snippet, amount):
     return "\n".join(ws + s if s else "" for s in snippet.split('\n'))
 
 
+def handle_singleline_env_vars(vars_):
+    # if the vars are all given on one line we need to do some work
+    if not '\n' in vars_:
+        keys = []
+        values = []
+        env_vars = vars_.split()
+        # split out the odd and even items into keys, values
+        for var in env_vars:
+            if divmod(env_vars.index(var) + 1, 2)[1]:
+                keys.append(var)
+            else:
+                values.append(var)
+        env_vars = zip(keys, values)
+        return '\n'.join(
+            ["%s %s" % (env_var[0], env_var[1]) for env_var in env_vars])
+    return vars_
+
+
 class Recipe(Scripts):
 
     def __init__(self, buildout, name, options):
@@ -161,7 +179,7 @@ def build_zope_conf(self):
         if not os.path.exists(var_dir):
             os.makedirs(var_dir)
 
-        instance_home = location
+        instance_home = options.get('instance-home', location)
         client_home = options.get('client-home', os.path.join(var_dir,
                                                               self.name))
         if not os.path.exists(client_home):
@@ -229,21 +247,12 @@ def build_zope_conf(self):
             ip_address = 'ip-address %s' % ip_address
         environment_vars = options.get('environment-vars', '')
         if environment_vars:
-            # if the vars are all given on one line we need to do some work
-            if not '\n' in environment_vars:
-                keys = []
-                values = []
-                env_vars = environment_vars.split()
-                # split out the odd and even items into keys, values
-                for var in env_vars:
-                    if divmod(env_vars.index(var) + 1, 2)[1]:
-                        keys.append(var)
-                    else:
-                        values.append(var)
-                env_vars = zip(keys, values)
-                environment_vars = '\n'.join(["%s %s" % (env_var[0], env_var[1])
-                                             for env_var in env_vars])
-            environment_vars = environment_template % environment_vars
+            environment_vars = environment_template % \
+                handle_singleline_env_vars(environment_vars)
+        cgi_environment_vars = options.get('cgi-environment-vars', '')
+        if cgi_environment_vars:
+            cgi_environment_vars = cgi_environment_template % \
+                handle_singleline_env_vars(cgi_environment_vars)
 
         deprecation_warnings = options.get('deprecation-warnings', '')
         if deprecation_warnings:
@@ -593,6 +602,7 @@ def is_rs_option(name):
                                     pid_file = pid_file,
                                     lock_file = lock_file,
                                     environment_vars = environment_vars,
+                                    cgi_environment_vars = cgi_environment_vars,
                                     deprecation_warnings = deprecation_warnings,
                                     python_check_interval = python_check_interval,
                                     enable_products = enable_products,
@@ -990,6 +1000,12 @@ def render_file_storage(self, file_storage, blob_storage,
 </environment>
 """
 
+cgi_environment_template = """
+<cgi-environment>
+    %s
+</cgi-environment>
+"""
+
 # The template used to build zope.conf
 zope_conf_template="""\
 %(imports_lines)s
@@ -1009,6 +1025,7 @@ def render_file_storage(self, file_storage, blob_storage,
 %(ip_address)s
 %(zserver_threads)s
 %(environment_vars)s
+%(cgi_environment_vars)s
 %(deprecation_warnings)s
 
 %(mailinglogger_import)s

src/plone/recipe/zope2instance/tests/zope2instance.txt

@@ -1788,6 +1788,44 @@ Our environment variables should be set now::
     >>> re.search(env_vars, zope_conf).group('vars')
     'TZ US/Eastern\nTMP /var/tmp\nDISABLE_PTS True'
 
+We can also specify CGI environment variables for Zope.  This comes handy when
+hosting on PaaS providers, such as Heroku, where we don't have a reverse-proxy
+in front of Zope. For example, we can configure Zope to run in HTTPS mode::
+
+    >>> write('buildout.cfg',
+    ... '''
+    ... [buildout]
+    ... parts = instance
+    ... find-links = %(sample_buildout)s/eggs
+    ...
+    ... [instance]
+    ... recipe = plone.recipe.zope2instance
+    ... eggs =
+    ... user = me:me
+    ... cgi-environment-vars = HTTPS ON
+    ... ''' % options)
+
+Let's run it::
+
+    >>> print system(join('bin', 'buildout')),
+    Uninstalling instance.
+    Installing instance.
+    Generated script '...instance'.
+    Generated interpreter '.../parts/instance/bin/interpreter'.
+    ...
+
+Our CGI environment variables should be set now::
+
+    >>> instance = os.path.join(sample_buildout, 'parts', 'instance')
+    >>> zope_conf = open(os.path.join(instance, 'etc', 'zope.conf')).read()
+    >>> zope_conf = zope_conf.replace('\\', '/')
+    >>> print zope_conf
+    %define INSTANCEHOME .../sample-buildout/parts/instance
+    ...
+    <cgi-environment>
+      HTTPS ON
+    </cgi-environment>
+    ...
 
 HTTP server
 ===========