sysrepo-plugin-generator

Sysrepo plugin generator based on main YANG modules used for the specific plugin.

Dependencies

• libyang
• Jinja2

Usage

Provide needed arguments for the script and run it to generate plugin directory code and structure.

$ python3 sysrepo-plugin-generator.py -h
usage: sysrepo-plugin-generator.py [-h] -d YANG_DIR -o OUT_DIR -c CONFIG -l LANG

Sysrepo plugin generator.

options:
  -h, --help            show this help message and exit
  -d YANG_DIR, --dir YANG_DIR
                        Directory containing all the yang modules.
  -o OUT_DIR, --outdir OUT_DIR
                        Output source directory to use.
  -c CONFIG, --config CONFIG
                        Configuration file to use for generation.
  -l LANG, --lang LANG  Destination language to generate to (C or C++).

Example

Generate the ietf-system plugin using the provided YANG modules and configuration:

$ python3 src/sysrepo-plugin-generator.py -d yang -o generated/ietf-system -l C -c config/ietf-system.toml

Build the generated plugin as a standalone executable (default):

$ cd generated/ietf-system
$ mkdir build && cd build
$ cmake ..
$ make -j

Build as a shared module (.so) for sysrepo-plugind:

$ cmake -DPLUGIN=1 ..
$ make -j

• PLUGIN=0 (default): builds a static library (.a) and a standalone executable that can run independently
• PLUGIN=1: builds a shared module (.so) that can be loaded by sysrepo-plugind

Available plugins

The following plugin configurations are available in the config/ folder:

Config	YANG module
ietf-access-control.toml	ietf-access-control-list
ietf-dhcpv6-client.toml	ietf-dhcpv6-client
ietf-interfaces.toml	ietf-interfaces
ietf-routing.toml	ietf-routing
ietf-system.toml	ietf-system

Generate and build a specific plugin:

$ python3 src/sysrepo-plugin-generator.py -d yang -o generated/ietf-access-control -l C -c config/ietf-access-control.toml
$ python3 src/sysrepo-plugin-generator.py -d yang -o generated/ietf-dhcpv6-client -l C -c config/ietf-dhcpv6-client.toml
$ python3 src/sysrepo-plugin-generator.py -d yang -o generated/ietf-interfaces -l C -c config/ietf-interfaces.toml
$ python3 src/sysrepo-plugin-generator.py -d yang -o generated/ietf-routing -l C -c config/ietf-routing.toml
$ python3 src/sysrepo-plugin-generator.py -d yang -o generated/ietf-system -l C -c config/ietf-system.toml

Then build the generated plugin:

$ cd generated/<plugin-name>
$ mkdir build && cd build
$ cmake ..
$ make -j

Generate and build all plugins at once:

$ for cfg in config/*.toml; do
    name=$(basename "$cfg" .toml)
    mkdir -p "generated/$name"
    python3 src/sysrepo-plugin-generator.py -d yang -o "generated/$name" -l C -c "$cfg"
    cd "generated/$name" && mkdir -p build && cd build && cmake .. && make -j
    cd ../../..
  done

Enabling YANG features in sysrepo

The generator enables all YANG features when generating plugin code. For the plugin to work correctly at runtime, the same features must be enabled in sysrepo. Otherwise, subscriptions to feature-gated paths (e.g. /ietf-system:system/radius/server) will fail with "not found" errors.

Enable all features for a module:

$ sudo sysrepoctl --change ietf-system --enable-feature '*'

Or enable specific features:

$ sudo sysrepoctl --change ietf-system --enable-feature radius --enable-feature authentication --enable-feature ntp

Check which features are currently enabled:

$ sysrepoctl -l | grep ietf-system

Directory structure

The generator will produce the following source directory structure (the example is taken for the ietf-system plugin):

|-- main.c
|-- plugin
|   |-- api
|   |   `-- system
|   |       |-- authentication
|   |       |   |-- change.c
|   |       |   |-- change.h
|   |       |   |-- check.c
|   |       |   |-- check.h
|   |       |   |-- load.c
|   |       |   |-- load.h
|   |       |   |-- store.c
|   |       |   `-- store.h
|   |       |-- change.c
|   |       |-- change.h
|   |       |-- check.c
|   |       |-- check.h
|   |       |-- clock
|   |       |   |-- change.c
|   |       |   |-- change.h
|   |       |   |-- check.c
|   |       |   |-- check.h
|   |       |   |-- load.c
|   |       |   |-- load.h
|   |       |   |-- store.c
|   |       |   `-- store.h
|   |       |-- dns-resolver
|   |       |   |-- change.c
|   |       |   |-- change.h
|   |       |   |-- check.c
|   |       |   |-- check.h
|   |       |   |-- load.c
|   |       |   |-- load.h
|   |       |   |-- options
|   |       |   |   |-- change.c
|   |       |   |   |-- change.h
|   |       |   |   |-- check.c
|   |       |   |   |-- check.h
|   |       |   |   |-- load.c
|   |       |   |   |-- load.h
|   |       |   |   |-- store.c
|   |       |   |   `-- store.h
|   |       |   |-- store.c
|   |       |   `-- store.h
|   |       |-- load.c
|   |       |-- load.h
|   |       |-- ntp
|   |       |   |-- change.c
|   |       |   |-- change.h
|   |       |   |-- check.c
|   |       |   |-- check.h
|   |       |   |-- load.c
|   |       |   |-- load.h
|   |       |   |-- store.c
|   |       |   `-- store.h
|   |       |-- radius
|   |       |   |-- change.c
|   |       |   |-- change.h
|   |       |   |-- check.c
|   |       |   |-- check.h
|   |       |   |-- load.c
|   |       |   |-- load.h
|   |       |   |-- options
|   |       |   |   |-- change.c
|   |       |   |   |-- change.h
|   |       |   |   |-- check.c
|   |       |   |   |-- check.h
|   |       |   |   |-- load.c
|   |       |   |   |-- load.h
|   |       |   |   |-- store.c
|   |       |   |   `-- store.h
|   |       |   |-- store.c
|   |       |   `-- store.h
|   |       |-- store.c
|   |       `-- store.h
|   |-- common.h
|   |-- context.h
|   |-- types.h
|   |-- data
|   |-- ly_tree.c
|   |-- ly_tree.h
|   |-- startup
|   |   |-- load.c
|   |   |-- load.h
|   |   |-- store.c
|   |   `-- store.h
|   `-- subscription
|       |-- change.c
|       |-- change.h
|       |-- operational.c
|       |-- operational.h
|       |-- rpc.c
|       `-- rpc.h
|-- plugin.c
`-- plugin.h

The main files are:

• main.c - plugin independent of sysrepo-plugind
• plugin.h - init and cleanup plugin callbacks
• plugin.c - init and cleanup implementation
• common.h - YANG paths and other commonly used macros
• context.h - context used throughout the plugin callbacks
• types.h - types used in the plugin (common structures, enums and unions)
• ly_tree.(h|c) - API for creating libyang tree nodes based on the main YANG module, here ietf-system

Other parts of the plugin include:

• plugin/api/ - the API for loading, storing and changing data on the system
• plugin/data/ - helper functions for types defined in types.h - example would be implementing init() and free() functionalities for a list of types - TODO
• plugin/startup/ - load and store functionalities for the startup datastore - initial load for startup when the plugin is first started, and constant store API for when the plugin starts up again so that the state is left unchanged
• plugin/subscription/ - change, operational and RPC/action callbacks, used in plugin.c file which subscribes all callbacks to their respective paths

plugin/data/ and plugin/api/ folders use separation based on the YANG containers - for each container one folder is used which enables easier navigation. In these folders, files can be separated based on more containers or lists etc.

Directory structure (C++)

The C++ generator produces the following source directory structure:

|-- main.cpp
|-- plugin.hpp
|-- plugin.cpp
`-- core
    |-- context.hpp
    |-- context.cpp
    |-- api
    |-- data
    |-- sub
    |   |-- change.cpp
    |   |-- change.hpp
    |   |-- oper.cpp
    |   |-- oper.hpp
    |   |-- rpc.cpp
    |   `-- rpc.hpp
    `-- yang
        |-- tree.cpp
        `-- tree.hpp

The main files are:

• main.cpp - standalone plugin independent of sysrepo-plugind
• plugin.hpp - init and cleanup plugin callbacks (extern "C")
• plugin.cpp - init and cleanup implementation
• core/context.(hpp|cpp) - plugin context with session, subscription handle, and sub-contexts for operational, module change, RPC and notification data

Other parts of the plugin include:

• core/api/ - the API for loading, storing and changing data on the system
• core/data/ - helper functions for plugin data types - TODO
• core/sub/ - subscription callbacks (module change, operational, RPC/action)
• core/yang/ - libyang tree API for creating nodes based on the main YANG module