Syntax and structure of federated configuration folders etc.

[LasseRosenow]

I try to summarize the state after our initial discussion.

In general when we are in a federated context, our program might consist of various federates that might even run on various platforms such as zephyr or riot.

[LasseRosenow]

1. We need to generate configuration folders for each federate (based on their platform)

Since the name of a federate is inferred from the LF file, it might be reasonable to generate the configuration folders etc. from within the LFC.

Following structure is currently implemented for zephyr:

- fed1
  - zephyr-config-file
- fed2
  - riot makefile
- src 
  - HelloLF.lf
- src-gen
  - HelloLF
    - fed1
    - fed2

Alternative Idea I just had:

- fed1
  - src-gen
  - zephyr-config-file
- fed2
  - src-gen 
  - riot makefile
- src 
  - HelloLF.lf

[LasseRosenow]

I guess the Idea is if you want to build fed1 for example you cd fed1 and then build as usual using the zephyr build system?
And for riot using make all? Which then keeps also running the LFC?

[LasseRosenow]

Another question:
How to we handle multiple LF_MAINs?
Right now we have namespace for different LF_MAINs in the src-gen folder.
should we also have that for the fed1 and fed2 configuraiton folders?

For example:

- HelloLF
  - fed1
    - zephyr-config-file
  - fed2
    - riot makefile
- src 
  - HelloLF.lf
- src-gen
  - HelloLF
    - fed1
    - fed2

or

- HelloLF
  - fed1
    - src-gen
    - zephyr-config-file
  - fed2
    - src-gen 
    - riot makefile
- src 
  - HelloLF.lf

or

- HelloLF
  - src
    - main.lf
  - fed1
    - src-gen
    - zephyr-config-file
  - fed2
    - src-gen 
    - riot makefile

[edwardalee]

I think we really do need to support having multiple main reactors in a project. It will be a very common use pattern to have multiple configurations and to compare them.

[tanneberger]

I think I prefer the last option:

Reasons:

• You probably have for every topology you have different configuration.
• No mixture of potentially only semi related subprojects.

[LasseRosenow]

2. We need a way to specify which federate uses wich platform:

Specify the platform per federate in LF using the @-syntax.

federated reactor {
  @platform(RIOT)
  fed1 = new MyFederate()

  @platform(Zephyr)
  fed2 = new MyFederate()
}

If the platform is not defined per federate, we might want to fall back to the default platform of the file

target uC {
  platform: RIOT,
  timeout: 1sec
}

federated reactor {
  fed1 = new MyFederate()
  fed2 = new MyFederate()
}

[tanneberger]

I think we really should go for the @type::feature() syntax otherwise we will have a big zoo of annotations.

I would like to see:

federated reactor {
  @federate::platform(riot)
  fed1 = new MyFederate()

  @federate::platform(zephyr)
  fed2 = new MyFederate()
}