sila2codegenerator 0.2.0

SiLA2 code generator for Python3

This package supplies a code generator that creates a working server and client prototype based on feature definition files and a service description file.

The codegenerator supports the SiLA2 server/client developer in two major tasks:

1. it converts the Feature Description File (FDL/XML) into a Protobuf .proto file

2. it generates a completely running SiLA server/client ( in simulation mode), where only the real/hardware specific code needs to be added/subclassed to the generated prototype code.

s.Tutorial for a fast introduction

Features

• .proto file generation out of FeatureDescription Files FDL/XML

• .proto file compilation

• complete server/client generation out of a project directory, containing a service_description file (s.hello_sila_project)

• support for Service/Device detection

• support for Service/Device feature detection

• switching between simulation and real (hardware) mode (+)

• default / standard Features (SiLAService, Sim, runcontrol, deviceinfo, …) (+)

• default error handling (+)

• sila-python-django support (+)

(+) under development

Installation

To install this library execute the following commands.

pip install -r requirements.txt
pip install .

This will also install the sila2lib package, if it is not installed yet. Since the packages from the requirements.txt file do no version check, you will have to run pip install --upgrade -r requirements.txt to force an upgrade to a new version.

It is highly recommended to work in the python3 virtual environment (default proposal of the installer): This ensures that the system Python setup is not affected. To activate the virtual environment, type

source [venv]/bin/activate

to deactivate it again, simply type (mind: here is no path required)

deactivate

Run

The code can be run using the command silacodegenerator. Use silacodegenerator --help to get an overview over the accepted arguments. The most common use will be

silacodegenerator --build <path/to/project/dir>

which, creates the .proto files, compiles them to the gRPC libraries and then builds server, client, servicer and implementation prototypes.

Templates

A strength of this CodeGenerator is the extensive usage of template files to generate the prototypes. Templates can be found in the package source under the templates directory. To chose which template to apply, call the code generator with the --template <template-name> flag.

Available templates are:

• run-inline: Based on the previous implementations. This templates generates calls to commands and properties of all features inside a run() method of the client class.

• run-method: For each command call and property the client implements its own method, effectively giving easy access to these data to a script from the outside. run() is still used to validate the connection to the server and retrieve basic server capabilities.

If you want to implement your own template, it is recommended to copy one existing template and then modify it. To use it during the build process, run the code generator with the flag --template-dir <path/to/template/directory>, which will overwrite the --template <..> flag and use the given directory as template source instead.

Example

The examples directory contains the hello_sila2_project. Building this project with the following command run inside the examples sub-directory will result in a new directory in the same folder which is named after the service name from the corresponding service description file.

.../examples> silacodegenerator --build hello_sila2_project

The new folder should have the following structure

HelloSiLA2
 + meta                             # the meta information, i.e. the FDL, proto
                                    #   and service description file
 + GreetingProvider
   # Additional information
   __init__.py                      # make this folder a python package
   # Implementations of the server, edit those for the actual implementation
   GreetingProvider_real.py         # the prototype for the real case
   GreetingProvider_simulation.py   # the prototype for the simulation case
   # Servicer
   GreetingProvoder_servicer.py     # The servicer that serves as a bridge between the
                                    #   server and the corresponding implementation
     + gRPC
      __init__.py                   # make this folder a python package
      # The auto-generated stub files.
      #     Do not Edit!
      GreetingProvider_pb2.py
      GreetingProvider_pb2-grpc.py

Proto file generation

If you only want to convert a SiLA2 Feature Description File (FDL) into a .proto file:

silacodegenerator [feature_descripton_file.xml]

This will result in a proto file with the output filename feature_descripton_file.proto

The output proto filename can be set with the -p option.

Example:

python3 silacodegenerator.py -f [feature_descripton_file.xml] -p my_protofilename.proto

Testing

To validate that the basic machinery is working correctly, please run the unittests:

cd [dir of codegenerator]

python -m unittest

Notes

• While in prior implementations the change between Simulation and Real mode relied on the Server and the inject_implementation() method of the servicer, this is now complete the responsibility of the servicer. It thus accepts the simulation_mode parameter at initialisation, and will thus either load the <Feature>Simulation or <Feature>Real implementation.