feat(unsupported): prevent formula running on unsupported minions

* https://freenode.logbot.info/saltstack-formulas/20190421#c2129159
* Use `failhard` to prevent execution if `unsupported` has been set
* Show reason(s) why minion is `unsupported`

template/config/clean.sls

@@ -3,10 +3,12 @@
 
 {#- Get the `tplroot` from `tpldir` #}
 {%- set tplroot = tpldir.split('/')[0] %}
+{%- set sls_fail_if_unsupported = tplroot ~ '.unsupported' %}
 {%- set sls_service_clean = tplroot ~ '.service.clean' %}
 {%- from tplroot ~ "/map.jinja" import template with context %}
 
 include:
+  - {{ sls_fail_if_unsupported }}
   - {{ sls_service_clean }}
 
 template-config-clean-file-absent:

template/config/file.sls

@@ -3,11 +3,13 @@
 
 {#- Get the `tplroot` from `tpldir` #}
 {%- set tplroot = tpldir.split('/')[0] %}
+{%- set sls_fail_if_unsupported = tplroot ~ '.unsupported' %}
 {%- set sls_package_install = tplroot ~ '.package.install' %}
 {%- from tplroot ~ "/map.jinja" import template with context %}
 {%- from tplroot ~ "/libtofs.jinja" import files_switch with context %}
 
 include:
+  - {{ sls_fail_if_unsupported }}
   - {{ sls_package_install }}
 
 template-config-file-file-managed:

template/osfingermap.yaml

@@ -10,11 +10,16 @@
 # the `os_finger` grain.
 ---
 # os: Ubuntu
+Ubuntu-14.04:
+  unsupported:
+    osfinger: 'Ubuntu 14.04 (does not use `systemd`).'
+Ubuntu-16.04: {}
 Ubuntu-18.04:
   config: /etc/template.d/custom-ubuntu-18.04.conf
 
 # os: CentOS
 CentOS-6:
-  pkg: template-centos-6
-  config: /etc/template.d/custom-centos-6.conf
-CentOS-7: {}
+  unsupported: 'CentOS 6 (does not use `systemd`).'
+CentOS-7:
+  pkg: template-centos-7
+  config: /etc/template.d/custom-centos-7.conf

template/package/clean.sls

@@ -3,10 +3,12 @@
 
 {#- Get the `tplroot` from `tpldir` #}
 {%- set tplroot = tpldir.split('/')[0] %}
+{%- set sls_fail_if_unsupported = tplroot ~ '.unsupported' %}
 {%- set sls_config_clean = tplroot ~ '.config.clean' %}
 {%- from tplroot ~ "/map.jinja" import template with context %}
 
 include:
+  - {{ sls_fail_if_unsupported }}
   - {{ sls_config_clean }}
 
 template-package-clean-pkg-removed:

template/package/install.sls

@@ -3,8 +3,12 @@
 
 {#- Get the `tplroot` from `tpldir` #}
 {%- set tplroot = tpldir.split('/')[0] %}
+{%- set sls_fail_if_unsupported = tplroot ~ '.unsupported' %}
 {%- from tplroot ~ "/map.jinja" import template with context %}
 
+include:
+  - {{ sls_fail_if_unsupported }}
+
 template-package-install-pkg-installed:
   pkg.installed:
     - name: {{ template.pkg }}

template/service/clean.sls

@@ -3,8 +3,12 @@
 
 {#- Get the `tplroot` from `tpldir` #}
 {%- set tplroot = tpldir.split('/')[0] %}
+{%- set sls_fail_if_unsupported = tplroot ~ '.unsupported' %}
 {%- from tplroot ~ "/map.jinja" import template with context %}
 
+include:
+  - {{ sls_fail_if_unsupported }}
+
 template-service-clean-service-dead:
   service.dead:
     - name: {{ template.service.name }}

template/service/running.sls

@@ -3,10 +3,12 @@
 
 {#- Get the `tplroot` from `tpldir` #}
 {%- set tplroot = tpldir.split('/')[0] %}
+{%- set sls_fail_if_unsupported = tplroot ~ '.unsupported' %}
 {%- set sls_config_file = tplroot ~ '.config.file' %}
 {%- from tplroot ~ "/map.jinja" import template with context %}
 
 include:
+  - {{ sls_fail_if_unsupported }}
   - {{ sls_config_file }}
 
 template-service-running-service-running:

template/unsupported.sls

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# vim: ft=sls
+
+{#- Get the `tplroot` from `tpldir` #}
+{%- set tplroot = tpldir.split('/')[0] %}
+{%- from tplroot ~ "/map.jinja" import template with context %}
+
+{%- if template.unsupported is defined %}
+template-unsupported-test-fail:
+  test.fail_without_changes:
+    - name: |
+
+
+        #######################################
+        # Unsupported minion for this formula #
+        #######################################
+        {%- for key, val in template.unsupported.items() %}
+        * {{ key }}: {{ val }}
+        {%- endfor %}
+    - failhard: True
+{%- endif %}