gitlab: Introduce macro library

Introduce a library of Jinja2 macros that will be handy to use in
templates. For now we add only 2 macros:

    cfg(name)   - to get instance configuration parameter `name`,   and
    cfg_bool    - to get truth value of ----//----

The reason we introduce cfg() is that we will need to use a lot of
parameters in many places and it is much more handy to write, e.g.

    cfg('email_enabled')

compared to

    instance_parameter:configuration.email_enabled

/cc @kazuhiko, @jerome

software/gitlab/instance-gitlab.cfg.in

@@ -127,6 +127,8 @@ mode    = 0700
 recipe  = slapos.recipe.template:jinja2
 extensions = jinja2.ext.do
 mode    = 0640
+import-list =
+    rawfile macrolib.cfg.in     {{ macrolib_cfg_in }}
 context =
     raw     autogenerated       # This file was autogenerated. (DO NOT EDIT - changes will be lost)
     section instance_parameter  instance-parameter

software/gitlab/instance.cfg.in

@@ -41,6 +41,7 @@ context =
     raw gitlab_parameters_cfg       ${gitlab-parameters.cfg:target}
     raw gitlab_shell_config_yml_in  ${gitlab-shell-config.yml.in:target}
     raw gitlab_yml_in               ${gitlab.yml.in:target}
+    raw macrolib_cfg_in             ${macrolib.cfg.in:target}
     raw rack_attack_rb_in           ${rack_attack.rb.in:target}
     raw resque_yml_in               ${resque.yml.in:target}
     raw smtp_settings_rb_in         ${smtp_settings.rb.in:target}

software/gitlab/macrolib.cfg.in

+{# common macros for gitlab instance #}
+
+{# cfg(name) -> instance_parameter:configuration.<name> #}
+{% macro cfg(name) %}{{ instance_parameter[str("configuration." + name)] }}{% endmacro %}
+
+{# cfg_bool(name) - like cfg(name), but returns 'true'/''
+   NOTE macros can return only strings - that's why '' is used for false #}
+{% macro cfg_bool(name) %}{{ 'true' if (cfg(name).lower() in ('true', 'yes')) else '' }}{% endmacro %}

software/gitlab/software.cfg

@@ -208,6 +208,10 @@ url     = ${:_profile_base_location_}/template/${:_buildout_section_name_}
 <= download-file
 # md5sum = TODO
 
+[macrolib.cfg.in]
+<= download-file
+# md5sum = TODO
+
 [rack_attack.rb.in]
 <= download-template
 # md5sum = TODO