Quick start¶

This section describes how to run the Hello world example available in the soure code at: hello example.

Clixon is not a system in itself, it is a support system for an application. In this case, the “application” is hello world. The hello world application is very simple where the application semantics is completely described by a YANG specification and a CLI specification.

A more advanced application will have backend (and frontend) plugins to add application-specific semantics. This is not necessary in the hello world application.

Content¶

The hello example directory contains the following files:

hello.xml: The configuration file. See clixon-config.yang for the uang spec of hello.xml.
clixon-hello@2019-04-17.yang: The yang spec of the example.
hello_cli.cli: CLIgen specification.
Makefile.in: Example makefile where plugins are built and installed
README.md: This file

Compile and run¶

Before you start, go through the install instructions.

make && sudo make install

Start backend in the background:

sudo clixon_backend

Start cli:

clixon_cli

Using the CLI¶

The example CLI allows you to modify and view the data model using set, delete and show via generated code.

The following example shows how to add a very simple configuration hello world using the generated CLI. The config is added to the candidate database, shown, committed to running, and then deleted.

olof@vandal> clixon_cli
cli> set <?>
  hello
cli> set hello world
cli> show configuration
hello world;
cli> commit
cli> delete <?>
  all                   Delete whole candidate configuration
  hello
cli> delete hello
cli> show configuration
cli> commit
cli> quit
olof@vandal>

Netconf¶

Clixon also provides a Netconf interface. The following example starts a netconf client form the shell, adds the hello world config, commits it, and shows it:

olof@vandal> clixon_netconf -q
<rpc><edit-config><target><candidate/></target><config><hello xmlns="urn:example:hello"><world/></hello></config></edit-config></rpc>]]>]]>
<rpc-reply><ok/></rpc-reply>]]>]]>
<rpc><commit/></rpc>]]>]]>
<rpc-reply><ok/></rpc-reply>]]>]]>
<rpc><get-config><source><running/></source></get-config></rpc>]]>]]>
<rpc-reply><data><hello xmlns="urn:example:hello"><world/></hello></data></rpc-reply>]]>]]>
olof@vandal>

Restconf¶

Clixon also provides a Restconf interface. A reverse proxy needs to be configured.

For example, using nginx on an Ubuntu release: install, and edit config file /etc/nginx/sites-available/default

server {
   ...
   location / {
      fastcgi_pass unix:/www-data/fastcgi_restconf.sock;
      include fastcgi_params;
   }
   # Enable this for restconf notification streams
   location /streams {
      fastcgi_pass unix:/www-data/fastcgi_restconf.sock;
      include fastcgi_params;
      proxy_http_version 1.1;
      proxy_set_header Connection "";
   }
}

Note that the second part is necessary only for notification streams.

Start nginx daemon

sudo /etc/init.d/nginx start

or using systemd:

sudo systemctl start nginx.service

Start the restconf daemon

sudo su -c "/www-data/clixon_restconf" -s /bin/sh www-data &

Start sending restconf commands (using Curl):

olof@vandal> curl -X POST http://localhost/restconf/data -d '{"clixon-hello:hello":{"world":null}}'
olof@vandal> curl -X GET http://localhost/restconf/data
{
   "data": {
     "clixon-hello:hello": {
       "world": null
     }
   }
}

Run a container¶

You can run the hello example as a pre-built docker container, on a x86_64 Linux. First, the container is started with the backend running:

docker run --rm --name hello -d clixon/clixon clixon_backend -Fs init

Then a CLI is started

$ sudo docker exec -it hello clixon_cli
cli> set ?
 hello
cli> set hello world
cli> show configuration
hello world;

Or Netconf:

$ sudo docker exec -it clixon/clixon clixon_netconf
<rpc><get-config><source><candidate/></source></get-config></rpc>]]>]]>
<rpc-reply><data/></rpc-reply>]]>]]>

Next steps¶

The hello world example only has a Yang spec and a template CLI spec. For more advanced applications, customized backend, CLI, netconf and restconf code callbacks becomes necessary.

Further, you may want to add upgrade, RPC:s, state data, notification streams, authentication and authorization. The main example. contains such capabilities.