gitlab/gitlab.yml: Handle "external URL"

GitLab has a notion of "external URL" - the canonical "frontend" URL the
server is reachable through: this URL is used as prefix to show
e.g. git-clone URL for repositories, etc, even if a server can be
reachable via several frontends.

Add external_url handling to slapos instance.

NOTE whether to use https or not is also defined by external_url, in
particular by external_url scheme.

/cc @kazuhiko, @jerome

software/gitlab/gitlab-parameters.cfg

@@ -9,6 +9,7 @@
 # (last updated for omnibus-gitlab 8.2.3+ce.0-0-g8eda093)
 
 [gitlab-parameters]
+configuration.external_url              = http://lab.example.com
 
 # db advanced
 configuration.db_pool                   = 10

software/gitlab/instance-gitlab.cfg.in

@@ -132,6 +132,7 @@ import-list =
 context =
     raw     autogenerated       # This file was autogenerated. (DO NOT EDIT - changes will be lost)
     section instance_parameter  instance-parameter
+    import  urlparse            urlparse
     ${:context-extra}
 context-extra =
 

software/gitlab/macrolib.cfg.in

@@ -6,3 +6,10 @@
 {# 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 %}
+
+
+{# deduce whether to use https from external url
+   ( here - becasue we cannot use jinja2 logic in instance-gitlab.cfg.in to
+     process instance parameters ) #}
+{% set external_url = urlparse.urlparse(cfg('external_url')) %}
+{% set cfg_https = (true if external_url.scheme == 'https' else false) %}

software/gitlab/template/gitlab.yml.in

@@ -4,6 +4,8 @@
 # https://gitlab.com/gitlab-org/omnibus-gitlab/blob/master/files/gitlab-cookbooks/gitlab/templates/default/gitlab.yml.erb
 # (last updated for omnibus-gitlab 8.2.3+ce.0-0-g8eda093)
 
+{% from 'macrolib.cfg.in' import cfg_https, external_url  with context %}
+
 production: &base
   #
   # 1. GitLab app settings
@@ -12,9 +14,10 @@ production: &base
   ## GitLab settings
   gitlab:
     ## Web server settings (note: host is the FQDN, do not include http://)
-    host: <%= @gitlab_host %>
-    port: <%= @gitlab_port %>
-    https: <%= @gitlab_https %>
+    {% set default_port = {'http': 80, 'https': 443} %}
+    host: {{ external_url.hostname }}
+    port: {{ external_url.port or default_port[external_url.scheme] }}
+    https: {{ cfg_https }}
 
     # Uncommment this line below if your ssh host is different from HTTP/HTTPS one
     # (you'd obviously need to replace ssh.host_example.com with your own host).