inifile: new implementation of setting updates to optimize reuse of comments and append location

Code comments should explain the algorithm, and test coverage suggest it works
correctly.

development.ini

@@ -1,514 +1,513 b''
 ###################################################################################
 ###################################################################################
 ## Kallithea config file generated with kallithea-config                         ##
 ##                                                                               ##
 ## The %(here)s variable will be replaced with the parent directory of this file ##
 ###################################################################################
 ###################################################################################
 
 [DEFAULT]
 
 ################################################################################
 ## Email settings                                                             ##
 ##                                                                            ##
 ## Refer to the documentation ("Email settings") for more details.            ##
 ##                                                                            ##
 ## It is recommended to use a valid sender address that passes access         ##
 ## validation and spam filtering in mail servers.                             ##
 ################################################################################
 
 ## 'From' header for application emails. You can optionally add a name.
 ## Default:
 #app_email_from = Kallithea
 ## Examples:
 #app_email_from = Kallithea <[e-mail]>
 #app_email_from = [e-mail]
 
 ## Subject prefix for application emails.
 ## A space between this prefix and the real subject is automatically added.
 ## Default:
 #email_prefix =
 ## Example:
 #email_prefix = [Kallithea]
 
 ## Recipients for error emails and fallback recipients of application mails.
 ## Multiple addresses can be specified, comma-separated.
 ## Only addresses are allowed, do not add any name part.
 ## Default:
 #email_to =
 ## Examples:
 #email_to = [e-mail]
 #email_to = [e-mail],[e-mail]
 email_to =
 
 ## 'From' header for error emails. You can optionally add a name.
 ## Default: (none)
 ## Examples:
 #error_email_from = Kallithea Errors <[e-mail]>
 #error_email_from = [e-mail]
 error_email_from =
 
 ## SMTP server settings
 ## If specifying credentials, make sure to use secure connections.
 ## Default: Send unencrypted unauthenticated mails to the specified smtp_server.
 ## For "SSL", use smtp_use_ssl = true and smtp_port = 465.
 ## For "STARTTLS", use smtp_use_tls = true and smtp_port = 587.
 smtp_server =
 smtp_username =
 smtp_password =
 smtp_port =
 smtp_use_ssl = false
 smtp_use_tls = false
 
 ## Entry point for 'gearbox serve'
 [server:main]
 #host = 127.0.0.1
 host = 0.0.0.0
 port = 5000
 
 ## WAITRESS ##
 use = egg:waitress#main
 ## number of worker threads
 threads = 1
 ## MAX BODY SIZE 100GB
 max_request_body_size = 107374182400
 ## use poll instead of select, fixes fd limits, may not work on old
 ## windows systems.
 #asyncore_use_poll = True
 
 ## middleware for hosting the WSGI application under a URL prefix
 #[filter:proxy-prefix]
 #use = egg:PasteDeploy#prefix
 #prefix = /<your-prefix>
 
 [app:main]
 use = egg:kallithea
 ## enable proxy prefix middleware
 #filter-with = proxy-prefix
 
 full_stack = true
 static_files = true
 
 ## Internationalization (see setup documentation for details)
 ## By default, the languages requested by the browser are used if available, with English as default.
 ## Set i18n.enabled=false to disable automatic language choice.
 #i18n.enabled = true
 ## To Force a language, set i18n.enabled=false and specify the language in i18n.lang.
 ## Valid values are the names of subdirectories in kallithea/i18n with a LC_MESSAGES/kallithea.mo
 #i18n.lang = en
 
 cache_dir = %(here)s/data
 index_dir = %(here)s/data/index
 
 ## uncomment and set this path to use archive download cache
 archive_cache_dir = %(here)s/tarballcache
 
 ## change this to unique ID for security
 #app_instance_uuid = VERY-SECRET
 app_instance_uuid = development-not-secret
 
 ## cut off limit for large diffs (size in bytes)
 cut_off_limit = 256000
 
 ## force https in Kallithea, fixes https redirects, assumes it's always https
 force_https = false
 
 ## use Strict-Transport-Security headers
 use_htsts = false
 
 ## number of commits stats will parse on each iteration
 commit_parse_limit = 25
 
 ## Path to Python executable to be used for git hooks.
 ## This value will be written inside the git hook scripts as the text
 ## after '#!' (shebang). When empty or not defined, the value of
 ## 'sys.executable' at the time of installation of the git hooks is
 ## used, which is correct in many cases but for example not when using uwsgi.
 ## If you change this setting, you should reinstall the Git hooks via
 ## Admin > Settings > Remap and Rescan.
 #git_hook_interpreter = /srv/kallithea/venv/bin/python3
 
 ## path to git executable
 git_path = git
 
 ## git rev filter option, --all is the default filter, if you need to
 ## hide all refs in changelog switch this to --branches --tags
 #git_rev_filter = --branches --tags
 
 ## RSS feed options
 rss_cut_off_limit = 256000
 rss_items_per_page = 10
 rss_include_diff = false
 
 ## options for showing and identifying changesets
 show_sha_length = 12
 show_revision_number = false
 
 ## Canonical URL to use when creating full URLs in UI and texts.
 ## Useful when the site is available under different names or protocols.
 ## Defaults to what is provided in the WSGI environment.
 #canonical_url = https://kallithea.example.com/repos
 
 ## gist URL alias, used to create nicer urls for gist. This should be an
 ## url that does rewrites to _admin/gists/<gistid>.
 ## example: http://gist.example.com/{gistid}. Empty means use the internal
 ## Kallithea url, ie. http[s]://kallithea.example.com/_admin/gists/<gistid>
 gist_alias_url =
 
 ## default encoding used to convert from and to unicode
 ## can be also a comma separated list of encoding in case of mixed encodings
 default_encoding = utf-8
 
 ## Set Mercurial encoding, similar to setting HGENCODING before launching Kallithea
 hgencoding = utf-8
 
 ## issue tracker for Kallithea (leave blank to disable, absent for default)
 #bugtracker = https://bitbucket.org/conservancy/kallithea/issues
 
 ## issue tracking mapping for commit messages, comments, PR descriptions, ...
 ## Refer to the documentation ("Integration with issue trackers") for more details.
 
 ## regular expression to match issue references
 ## This pattern may/should contain parenthesized groups, that can
 ## be referred to in issue_server_link or issue_sub using Python backreferences
 ## (e.g. \1, \2, ...). You can also create named groups with '(?P<groupname>)'.
 ## To require mandatory whitespace before the issue pattern, use:
 ## (?:^|(?<=\s)) before the actual pattern, and for mandatory whitespace
 ## behind the issue pattern, use (?:$|(?=\s)) after the actual pattern.
 
 issue_pat = #(\d+)
 
 ## server url to the issue
 ## This pattern may/should contain backreferences to parenthesized groups in issue_pat.
 ## A backreference can be \1, \2, ... or \g<groupname> if you specified a named group
 ## called 'groupname' in issue_pat.
 ## The special token {repo} is replaced with the full repository name
 ## including repository groups, while {repo_name} is replaced with just
 ## the name of the repository.
 
 issue_server_link = https://issues.example.com/{repo}/issue/\1
 
 ## substitution pattern to use as the link text
 ## If issue_sub is empty, the text matched by issue_pat is retained verbatim
 ## for the link text. Otherwise, the link text is that of issue_sub, with any
 ## backreferences to groups in issue_pat replaced.
 
 issue_sub =
 
 ## issue_pat, issue_server_link and issue_sub can have suffixes to specify
 ## multiple patterns, to other issues server, wiki or others
 ## below an example how to create a wiki pattern
 ## wiki-some-id -> https://wiki.example.com/some-id
 
 #issue_pat_wiki = wiki-(\S+)
 #issue_server_link_wiki = https://wiki.example.com/\1
 #issue_sub_wiki = WIKI-\1
 
 ## alternative return HTTP header for failed authentication. Default HTTP
 ## response is 401 HTTPUnauthorized. Currently Mercurial clients have trouble with
 ## handling that. Set this variable to 403 to return HTTPForbidden
 auth_ret_code =
 
 ## allows to change the repository location in settings page
 allow_repo_location_change = True
 
 ## allows to setup custom hooks in settings page
 allow_custom_hooks_settings = True
 
 ## extra extensions for indexing, space separated and without the leading '.'.
 #index.extensions =
 #    gemfile
 #    lock
 
 ## extra filenames for indexing, space separated
 #index.filenames =
 #    .dockerignore
 #    .editorconfig
 #    INSTALL
 #    CHANGELOG
 
 ####################################
 ###           SSH CONFIG        ####
 ####################################
 
 ## SSH is disabled by default, until an Administrator decides to enable it.
 ssh_enabled = false
 
 ## File where users' SSH keys will be stored *if* ssh_enabled is true.
 #ssh_authorized_keys = /home/kallithea/.ssh/authorized_keys
 
 ## Path to be used in ssh_authorized_keys file to invoke kallithea-cli with ssh-serve.
 #kallithea_cli_path = /srv/kallithea/venv/bin/kallithea-cli
 
 ## Locale to be used in the ssh-serve command.
 ## This is needed because an SSH client may try to use its own locale
 ## settings, which may not be available on the server.
 ## See `locale -a` for valid values on this system.
 #ssh_locale = C.UTF-8
 
 ####################################
 ###        CELERY CONFIG        ####
 ####################################
 
 ## Note: Celery doesn't support Windows.
 use_celery = false
 
 ## Celery config settings from https://docs.celeryproject.org/en/4.4.0/userguide/configuration.html prefixed with 'celery.'.
 
 ## Example: use the message queue on the local virtual host 'kallitheavhost' as the RabbitMQ user 'kallithea':
 celery.broker_url = amqp://kallithea:thepassword@localhost:5672/kallitheavhost
 
 celery.result.backend = db+sqlite:///celery-results.db
 
 #celery.amqp.task.result.expires = 18000
 
 celery.worker_concurrency = 2
 celery.worker_max_tasks_per_child = 1
 
 ## If true, tasks will never be sent to the queue, but executed locally instead.
 celery.task_always_eager = false
 
 ####################################
 ###         BEAKER CACHE        ####
 ####################################
 
 beaker.cache.data_dir = %(here)s/data/cache/data
 beaker.cache.lock_dir = %(here)s/data/cache/lock
 
 beaker.cache.regions = long_term,long_term_file
 
 beaker.cache.long_term.type = memory
 beaker.cache.long_term.expire = 36000
 beaker.cache.long_term.key_length = 256
 
 beaker.cache.long_term_file.type = file
 beaker.cache.long_term_file.expire = 604800
 beaker.cache.long_term_file.key_length = 256
 
 ####################################
 ###       BEAKER SESSION        ####
 ####################################
 
 ## Name of session cookie. Should be unique for a given host and path, even when running
 ## on different ports. Otherwise, cookie sessions will be shared and messed up.
 session.key = kallithea
 ## Sessions should always only be accessible by the browser, not directly by JavaScript.
 session.httponly = true
 ## Session lifetime. 2592000 seconds is 30 days.
 session.timeout = 2592000
 
 ## Server secret used with HMAC to ensure integrity of cookies.
 #session.secret = VERY-SECRET
 session.secret = development-not-secret
 ## Further, encrypt the data with AES.
 #session.encrypt_key = <key_for_encryption>
 #session.validate_key = <validation_key>
 
 ## Type of storage used for the session, current types are
 ## dbm, file, memcached, database, and memory.
 
 ## File system storage of session data. (default)
 #session.type = file
 
 ## Cookie only, store all session data inside the cookie. Requires secure secrets.
 #session.type = cookie
 
 ## Database storage of session data.
 #session.type = ext:database
 #session.sa.url = postgresql://postgres:qwe@localhost/kallithea
 #session.table_name = db_session
 
 ############################
 ## ERROR HANDLING SYSTEMS ##
 ############################
 
 ## Propagate email settings to ErrorReporter of TurboGears2
 ## You do not normally need to change these lines
 get trace_errors.smtp_server = smtp_server
 get trace_errors.smtp_port = smtp_port
 get trace_errors.from_address = error_email_from
 get trace_errors.error_email = email_to
 get trace_errors.smtp_username = smtp_username
 get trace_errors.smtp_password = smtp_password
 get trace_errors.smtp_use_tls = smtp_use_tls
 
 ################################################################################
 ## WARNING: *DEBUG MODE MUST BE OFF IN A PRODUCTION ENVIRONMENT*              ##
 ## Debug mode will enable the interactive debugging tool, allowing ANYONE to  ##
 ## execute malicious code after an exception is raised.                       ##
 ################################################################################
 #debug = false
 debug = true
 
 ##################################
 ###       LOGVIEW CONFIG       ###
 ##################################
 
 logview.sqlalchemy = #faa
 logview.pylons.templating = #bfb
 logview.pylons.util = #eee
 
 #########################################################
 ### DB CONFIGS - EACH DB WILL HAVE IT'S OWN CONFIG    ###
 #########################################################
 
 ## SQLITE [default]
 sqlalchemy.url = sqlite:///%(here)s/kallithea.db?timeout=60
 
 ## see sqlalchemy docs for other backends
 
 sqlalchemy.pool_recycle = 3600
 
 ################################
 ### ALEMBIC CONFIGURATION   ####
 ################################
 
 [alembic]
 script_location = kallithea:alembic
 
 ################################
 ### LOGGING CONFIGURATION   ####
 ################################
 
 [loggers]
 keys = root, routes, kallithea, sqlalchemy, tg, gearbox, beaker, templates, whoosh_indexer, werkzeug, backlash
 
 [handlers]
 keys = console, console_color, console_color_sql, null
 
 [formatters]
 keys = generic, color_formatter, color_formatter_sql
 
 #############
 ## LOGGERS ##
 #############
 
 [logger_root]
 level = NOTSET
 #handlers = console
+## For coloring based on log level:
 handlers = console_color
-## For coloring based on log level:
-#handlers = console_color
 
 [logger_routes]
 #level = WARN
 level = DEBUG
 handlers =
 qualname = routes.middleware
 ## "level = DEBUG" logs the route matched and routing variables.
 
 [logger_beaker]
 #level = WARN
 level = DEBUG
 handlers =
 qualname = beaker.container
 
 [logger_templates]
 #level = WARN
 level = INFO
 handlers =
 qualname = pylons.templating
 
 [logger_kallithea]
 #level = WARN
 level = DEBUG
 handlers =
 qualname = kallithea
 
 [logger_tg]
 #level = WARN
 level = DEBUG
 handlers =
 qualname = tg
 
 [logger_gearbox]
 #level = WARN
 level = DEBUG
 handlers =
 qualname = gearbox
 
 [logger_sqlalchemy]
 level = WARN
 handlers =
 qualname = sqlalchemy.engine
 ## For coloring based on log level and pretty printing of SQL:
 #level = INFO
 #handlers = console_color_sql
 #propagate = 0
 
 [logger_whoosh_indexer]
 #level = WARN
 level = DEBUG
 handlers =
 qualname = whoosh_indexer
 
 [logger_werkzeug]
 level = WARN
 handlers =
 qualname = werkzeug
 
 [logger_backlash]
 level = WARN
 handlers =
 qualname = backlash
 
 ##############
 ## HANDLERS ##
 ##############
 
 [handler_console]
 class = StreamHandler
 args = (sys.stderr,)
 formatter = generic
 
 [handler_console_color]
 ## ANSI color coding based on log level
 class = StreamHandler
 args = (sys.stderr,)
 formatter = color_formatter
 
 [handler_console_color_sql]
 ## ANSI color coding and pretty printing of SQL statements
 class = StreamHandler
 args = (sys.stderr,)
 formatter = color_formatter_sql
 
 [handler_null]
 class = NullHandler
 args = ()
 
 ################
 ## FORMATTERS ##
 ################
 
 [formatter_generic]
 format = %(asctime)s.%(msecs)03d %(levelname)-5.5s [%(name)s] %(message)s
 datefmt = %Y-%m-%d %H:%M:%S
 
 [formatter_color_formatter]
 class = kallithea.lib.colored_formatter.ColorFormatter
 format = %(asctime)s.%(msecs)03d %(levelname)-5.5s [%(name)s] %(message)s
 datefmt = %Y-%m-%d %H:%M:%S
 
 [formatter_color_formatter_sql]
 class = kallithea.lib.colored_formatter.ColorFormatterSql
 format = %(asctime)s.%(msecs)03d %(levelname)-5.5s [%(name)s] %(message)s
 datefmt = %Y-%m-%d %H:%M:%S
 
 #################
 ## SSH LOGGING ##
 #################
 
 ## The default loggers use 'handler_console' that uses StreamHandler with
 ## destination 'sys.stderr'. In the context of the SSH server process, these log
 ## messages would be sent to the client, which is normally not what you want.
 ## By default, when running ssh-serve, just use NullHandler and disable logging
 ## completely. For other logging options, see:
 ## https://docs.python.org/2/library/logging.handlers.html
 
 [ssh_serve:logger_root]
 level = CRITICAL
 handlers = null
 
 ## Note: If logging is configured with other handlers, they might need similar
 ## muting for ssh-serve too.

kallithea/lib/inifile.py

@@ -1,199 +1,220 b''
 # -*- coding: utf-8 -*-
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # 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/>.
 
 """
 kallithea.lib.inifile
 ~~~~~~~~~~~~~~~~~~~~~
 
 Handling of .ini files, mainly creating them from Mako templates and adding
 other custom values.
 """
 
 import logging
 import os
 import re
 
 import mako.template
 
 
 log = logging.getLogger(__name__)
 
 
 template_file = os.path.join(
     os.path.dirname(os.path.dirname(os.path.dirname(__file__))),
     'kallithea/lib/paster_commands/template.ini.mako')
 
 default_variables = {
     'database_engine': 'sqlite',
     'http_server': 'waitress',
     'host': '127.0.0.1',
     'port': '5000',
     'uuid': lambda: 'VERY-SECRET',
 }
 
 variable_options = {
     'database_engine': ['sqlite', 'postgres', 'mysql'],
     'http_server': ['waitress', 'gearbox', 'gevent', 'gunicorn', 'uwsgi'],
 }
 
 def expand(template, mako_variable_values, settings):
     """Expand mako template and tweak it.
     Not entirely stable for random templates as input, but good enough for our
     single template.
 
     >>> template = '''
     ... [first-section]
     ...
     ... variable=${mako_variable}
     ... variable2  =\tvalue after tab
     ... ## This section had some whitespace and stuff
     ...
     ...
     ... # ${mako_function()}
     ... [second-section]
     ... %if conditional_options == 'option-a':
     ... # option a was chosen
     ... %elif conditional_options == 'option-b':
     ... some_variable = "never mind - option-b will not be used anyway ..."
     ... %endif
     ...
     ... [comment-section]
     ... #variable3 = 3.0
     ... #variable4 = 4.0
     ... #variable5 = 5.0
     ... variable5 = 5.1
     ... #variable6 = 6.0
     ... #variable6 = 6.1
     ... #variable7 = 7.0
     ... variable7 = 7.1
     ... '''
     >>> mako_variable_values = {'mako_variable': 'VALUE', 'mako_function': (lambda: 'FUNCTION RESULT'),
     ...                         'conditional_options': 'option-a', 'http_server': 'nc'}
     >>> settings = { # only partially used
     ...     '[first-section]': {'variable2': 'VAL2', 'first_extra': 'EXTRA'},
     ...     '[comment-section]': {'variable3': '3.0', 'variable4': '4.1', 'variable5': '5.2', 'variable6': '6.2', 'variable7': '7.0'},
     ...     '[third-section]': {'third_extra': ' 3'},
     ...     '[fourth-section]': {'fourth_extra': '4', 'fourth': '"four"'},
     ... }
     >>> print(expand(template, mako_variable_values, settings))
     ERROR: http_server is 'nc' - it should be one of 'waitress', 'gearbox', 'gevent', 'gunicorn', 'uwsgi'
     <BLANKLINE>
     [first-section]
     <BLANKLINE>
     variable=VALUE
     #variable2  =    value after tab
     variable2 = VAL2
     <BLANKLINE>
     first_extra = EXTRA
     <BLANKLINE>
     <BLANKLINE>
     # FUNCTION RESULT
     [second-section]
     # option a was chosen
     <BLANKLINE>
     [comment-section]
-    #variable3 = 3.0
+    variable3 = 3.0
     #variable4 = 4.0
+    variable4 = 4.1
     #variable5 = 5.0
     #variable5 = 5.1
     variable5 = 5.2
     #variable6 = 6.0
     #variable6 = 6.1
-    #variable7 = 7.0
-    #variable7 = 7.1
+    variable6 = 6.2
     variable7 = 7.0
-    <BLANKLINE>
-    variable3 = 3.0
-    variable4 = 4.1
-    variable6 = 6.2
+    #variable7 = 7.1
     <BLANKLINE>
     [fourth-section]
     fourth = "four"
     fourth_extra = 4
     <BLANKLINE>
     [third-section]
     third_extra =  3
     <BLANKLINE>
     """
     mako_variables = dict(default_variables)
     mako_variables.update(mako_variable_values or {})
     settings = dict((k, dict(v)) for k, v in settings.items()) # deep copy before mutating
 
     for key, value in mako_variables.items():
         if key in variable_options:
             if value not in variable_options[key]:
                 print('ERROR: %s is %r - it should be one of %s' %
                       (key, value, ', '.join(repr(x) for x in variable_options[key])))
 
     ini_lines = mako.template.Template(template).render(**mako_variables)
 
     def process_section(m):
         """process a ini section, replacing values as necessary"""
         sectionname, lines = m.groups()
         if sectionname in settings:
             section_settings = settings.pop(sectionname)
+            add_after_key_value = {}  # map key to value it should be added after
 
-            def process_line(m):
-                """process a section line and update value if necessary"""
-                key, value = m.groups()
+            # 1st pass:
+            # comment out lines with keys that have new values
+            # find best line for keeping or un-commenting (because it has the right value) or adding after (because it is the last with other value)
+            def comment_out(m):
+                """process a section line if in section_settings and comment out and track in add_after_key_value"""
                 line = m.group(0)
-                if key in section_settings:
-                    new_line = '%s = %s' % (key, section_settings.pop(key))
-                    if new_line != line:
-                        # keep old entry as example - comments might refer to it
-                        line = '#%s\n%s' % (line, new_line)
-                return line.rstrip()
+                comment, key, line_value = m.groups()
+                if key not in section_settings:
+                    return line
+                new_value = section_settings[key]
+                if line_value == new_value or add_after_key_value.get(key) != new_value:
+                    add_after_key_value[key] = line_value
+                if comment:
+                    return line
+                return '#' + line
+
+            lines = re.sub(r'^(#)?([^#\n\s]*)[ \t]*=[ \t]*(.*)$', comment_out, lines, flags=re.MULTILINE)
 
-            # process lines that not are comments or empty and look like name=value
-            lines = re.sub(r'^([^#\n\s]*)[ \t]*=[ \t]*(.*)$', process_line, lines, flags=re.MULTILINE)
+            def add_after_comment(m):
+                """process a section comment line and add new value"""
+                line = m.group(0)
+                key, line_value = m.groups()
+                if key not in section_settings:
+                    return line
+                if line_value != add_after_key_value.get(key):
+                    return line
+                new_value = section_settings[key]
+                if new_value == line_value:
+                    line = line.lstrip('#')
+                else:
+                    line += '\n%s = %s' % (key, new_value)
+                section_settings.pop(key)
+                return line
+
+            lines = re.sub(r'^#([^#\n\s]*)[ \t]*=[ \t]*(.*)$', add_after_comment, lines, flags=re.MULTILINE)
+
             # add unused section settings
             if section_settings:
                 lines += '\n' + ''.join('%s = %s\n' % (key, value) for key, value in sorted(section_settings.items()))
 
         return sectionname + '\n' + lines
 
     # process sections until comments before next section or end
     ini_lines = re.sub(r'''^
         (\[.*\])\n
         # after the section name, a number of chunks with:
         (
             (?:
                 # a number of comments or empty lines
                 (?:[#].*\n|\n)*
                 # one or more non-empty non-comments non-section-start lines
                 (?:[^\n#[].*\n)+
                 # a number of comments - not empty lines
                 (?:[#].*\n)*
             )*
         )
         ''',
         process_section, ini_lines, flags=re.MULTILINE | re.VERBOSE) \
         + \
         ''.join(
             '\n' + sectionname + '\n' + ''.join('%s = %s\n' % (key, value) for key, value in sorted(section_settings.items()))
             for sectionname, section_settings in sorted(settings.items())
             if section_settings)
 
     return ini_lines
 
 
 def create(dest_file, mako_variable_values, settings):
     """Create an ini file at dest_file"""
     with open(template_file, 'rb') as f:
         template = f.read().decode('utf-8')
 
     ini_lines = expand(template, mako_variable_values, settings)
 
     with open(dest_file, 'wb') as f:
         f.write(ini_lines.encode('utf-8'))