Table of Contents
In this chapter, we are giving an overview about how the Technique Editor works and how it is integrated with the main Rudder application.
As explained in http://www.ncf.io/, ncf uses a structured directory tree composed of several layers of logic, from internal libraries to Techniques and user services. All the files and logic in these folders will be named "library" for simplicity
ncf directory structure exists in two root folders:
-
/usr/share/ncf/tree
- This is the standard library installation folder. It is created and updated by the the ncf package. This folder will be completely overwritten when you update ncf package so you should never modify anything here: it will be lost at some point.
-
/var/rudder/configuration-repository/ncf
- This is were you add your own ncf Generic Methods and Techniques. Techniques created with the Technique Editor will be located here, and both Generic Methods and Techniques in that place will be accessible in the Technique Editor alongside what is provided by the standard library.
To share those folders to all nodes, Rudder makes a copy of these folders in /var/rudder/ncf:
- /var/rudder/ncf/local is a copy of /var/rudder/configuration-repository/ncf
- /var/rudder/ncf/common is a copy /usr/share/ncf/tree
They are synchronized automatically by the agent running on the server. So any modification done in files in these directories will be lost at the next synchronization.
A node updates its ncf local library by copying the content of these two folders during its promise update phase.
Here we will explain Technique Editor behavior and what workflow are initialized by different action on the Technique Editor.
Each action in the Technique Editor interface produces requests to an API defined over ncf.
All of the requests are authenticated thanks to a token passed in the JSESSIONID header. The token is generated when an authenticated user is connected to the Rudder interface (typically thanks to his browser).
That token is shared to the Technique Editor interface, which itself passes the JSESSIONID header to all requests.
If you have authentication issue, check that your Rudder session is not expired.
- Get request
- Get request will get all Techniques and Generic Methods in a path passed as parameters of the request in the "path" javascript variable:
https://your.rudder.server/ncf-builder/#!?path=/var/rudder/configuration-repository/ncf
Get requests are triggered when accessing Technique editor.
The ncf API will parse all files in the parameter path by running "cf-promises -pjson" on all Techniques, checking that all Techniques are correctly formed.
The ncf API will also look to all Generic Methods description data to build the catalog of available Generic Methods.
The resulting information are sent back to the Technique Editor for displaying.
- Post requests
- Post requests are issued when a Technique is created, modified or deleted. They will only work on Techniques available in the path given in parameter.
They are triggered when clicking on save/delete button.
The main difference with get requests is that hooks are launched before and after the action is made.
We will see all hooks behavior in the following dedicated hooks section.
On each POST request, pre- and post- hooks are executed by the Technique Editor. These hooks are used for the Rudder integration to help transform pure ncf Techniques into Rudder one.
- pre-hooks are located in: /var/rudder/configuration-repository/ncf/pre-hooks.d
- post-hooks are located in: /var/rudder/configuration-repository/ncf/post-hooks.d
As of March 2015, we have two post-hooks defined and no pre-hooks:
-
post.write_technique.commit.sh
- It commits the Technique newly created into Rudder Git configuration repository located in /var/rudder/configuration-repository.
-
post.write_technique.rudderify.sh
- It generates a valid Rudder Technique from a the newly created Technique and reloads Rudder Technique Library so that updates are taken into account.
If you want to run post hooks by hand, you can use the following command:
/var/rudder/configuration-repository/ncf/post-hooks.d/post.write_technique.commit.sh /var/rudder/configuration-repository bundle_name
