Document Condition command

doc/index.rst

@@ -14,6 +14,7 @@ Contents:
    info/index
    running/index
    scheduler/index
+   render/index
    deploy-tutorial
    changelog
 

doc/render/commands.rst

@@ -0,0 +1,38 @@
+Render Commands
+===============
+
+
+Condition
+---------
+
+Condition is a special command that executes other commands only if some
+condition happens.
+
+Example:
+
+.. code-block: yaml
+
+   templates:
+     nginx: nginx.conf.trm
+   commands:
+   - !Copy
+     src: "{{ templates.nginx }}"
+     target: /etc/nginx/nginx.conf
+   - !Condition
+     dirs-changed: [/etc/nginx]
+     commands:
+     - !RootCommand [pkill, -HUP, nginx]
+
+Conditions:
+
+``dirs-changed``
+    Calculates hash of all files in the directory recursively at the beginning
+    of the **processing this .render.yaml** file. Then the hashsum is checked
+    again when ``!Condition`` is encountered and if hashsum changed
+    ``commands`` are executed, otherwise they are silently skipped.
+
+Options:
+
+``commands``
+   List of commands to execute when condition is true. All the same commands
+   suported except the ``!Condition`` itself.

doc/render/index.rst

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+Writing Renderers
+=================
+
+Renderer is a subsystem that executes all necessary steps to apply
+verwalter schedule/configuration on each machine
+
+Contents:
+
+.. toctree::
+   :maxdepth: 2
+
+   commands