[ModelicaSystem] only local omc process allowed

[syntron]

ModelicaSystem relies on read access to files and the possibility to execute the compiled model; thus, it only works if OMC is started locally

Use OMCProcessLocal to ensure that this requirement is defined

Based on PR #295

[adeas31]

Does this mean we can't use docker and wsl instances with ModelicaSystem? Is this just because if I/O permission issues?

[syntron]

Does this mean we can't use docker and wsl instances with ModelicaSystem? Is this just because if I/O permission issues?

@adeas31 no, the reason is that ModelicaSystem accesses the file system directly without using OMC (create csv file; read result data, etc.). Due to this, the class can only used locally ...

[syntron]

Here some more analyses:

ModelicaSystem(Cmd) are using Python functions to access files from the OMC model; if this code is replaced by calls to OMC, the ModelicaSystem classes would be completly independent from the use OMCSessionZMQ(OMCProcess) version used.

However, it would also mean, that some simple functionality is replaced by code which has to go through OMC in the case of a local usage - but it should be possible to abstract the access to the local filesystem! Thus, ModelicaSystem can be used for all systems for which OMCSessionZMQ is defined.

Use cases (line numbers based on master):

• pathlib.Path().exists() / pathlib.Path().is_file() / pathlib.is_dir()
  • L246 ModelicaSystemCmd.run() - check for *.bat file
  • L426 ModelicaSystem.init() - check if fileName exists
  • L486 ModelicaSystem.setTempDirectory() - check if dir exists + mkdir + check again
  • L543 ModelicaSystem.xmlparse() - check if *.xml file exists
  • L887 / L929 / L934 ModelicaSystem.simulate() - check if resultfile exists
  • L958 ModelicaSystem.getSolution() - check if resultfile exists
  • L1217 ModelicaSystem.convertMo2FMU() - check if file exists
  • L1234 ModelicaSystem.convertFMU2Mo() - check if file exists
  • L1332 / L1335 ModelicaSystem.linearize() - check if linearFile exists - python file!
  • => https://build.openmodelica.org/Documentation/OpenModelica.Scripting.regularFileExists.html
  • => https://build.openmodelica.org/Documentation/OpenModelica.Scripting.mkdir.html
  • => https://build.openmodelica.org/Documentation/OpenModelica.Scripting.directoryExists.html
• open(r)
  • L249 ModelicaSystemCmd.run() - open for *.bat file (read all content)
  • L546 ModelicaSystem.xmlparse() - read file via xml.etree.ElementTree - could be replaced by open() / write temp / read
  • => https://build.openmodelica.org/Documentation/OpenModelica.Scripting.readFile.html
• open(w)
  • L906 ModelicaSystem.simulate() - write overridefile
  • L1190 ModelicaSystem.createCSVData() - write csvfile
  • L1294 ModelicaSystem.linearize() - write overrideLinearFile
  • => https://build.openmodelica.org/Documentation/OpenModelica.Scripting.writeFile.html
• unlink
  • L930 ModelicaSystem.simulate() - remove resultfile from previous run
  • => https://build.openmodelica.org/Documentation/OpenModelica.Scripting.remove.html

[syntron]

Another big issue is the call to the executable in simulate() and linearize() using ModelicaSystemCmd(). A solution for this case is also needed - how to call / run the executable from the host within docker / wsl and also local?

[syntron]

Another point: if the model executeable is used, the evaluation of the library paths is done for Windows (using *.bat file). However, I never tested this part for linux (docker, wsl). How can we ensure, that the needed (external) libraries are found in this case?