NS3 CI Checker

This action is used to test NS3 simulation code to check that it builds and that a simple simulation can run without crashing.

This action can be used to check your code for multiple versions of ns-3, currently this will support ns-3.32, ns-3.33, ns-3.34, and ns-3.35. If you wish to see a different version of ns3 supported by this action open an issue and Id be happy to add support for it.

Motivation

The ns-3 network simulation platform is an interesting codebase that is different from most other library projects, where instead of including the simulator as a project dependency the simulation code needs to be written inside of the simulator code. This presents some challenges with doing CI/CD testing on the simulation code that is being written because you can not check to make sure that the code compiles without also compiling the entire simulator as well. This is an extremely time consuming process (the github action to build this container takes about 23 minutes to run), that is no good for a simple "does this compile check", hence this project.

Building

This repository is not meant to be built or used on its own, however it can be built manually. The only dependency needed to build this is docker, and more than 2 GB of ram, I think 4GB might be needed or it will crash part way through.

$ docker build \
    --build-arg VCS_REF=$(git rev-parse -q --verify HEAD) \
    --build-arg BUILD_DATE=$(date -u +"%Y-%m-%dT%H:%M:%SZ") \
    --build-arg NS3_VERSION=3.32 \
    -t marshallasch/ns3-action .

By default it will use ns-3 version 3.32, as that is the version of the simulator that I am using for my research. But a different version can be specified:

$ docker build --build-arg NS3_VERSION=3.33 marshallasch/ns3-action .

Usage

Inputs

sim_name

optional The extra options that are passed to the ./waf --run "<simulation name> <options>" to test run the simulation. Only specify this if the location is being set to something other than scratch, otherwise it is ignored.

sim_args

optional The extra options that are passed to the ./waf --run "<simulation name> <options>" to test run the simulation. It is also important to note that this container is not designed to actually run simulations in and these arguments should be selected so that the smallest possible simulation can be run to ensure that the code works.

pre_run

optional A script that can be specified to run before the simulation code get compiled or run.

Note that this will be run from the NS3 directory, the script directory must be relative to the repository root and should not include a leading '/' The ns-3 root installation location can be accessed through the NS3_ROOT envirionment variable. The module can be accessed through the NS3_MODULE environment variable.

post_run

optional A script that can be specified to run before the simulation code get compiled or run. If this is specified then the return value of this script is used.

Note that this will be run from the NS3 directory, the script directory must be relative to the repository root and should not include a leading '/' The ns-3 root installation location can be accessed through the NS3_ROOT envirionment variable.
The module can be accessed through the NS3_MODULE environment variable.

location

optional The location that the simulation code should be copied. This should only be one of scratch, src, or contrib. The value will default to scratch if it is not set. If it is set to scratch then the sim_name field is optional, for any other value it is required.

Also note that there is no output that is collected from this container and it is only used to check that 1) the code builds, and 2) that the code runs without crashing.

Example usage

name: build-ns3

on: [push, pull_request]

jobs:
  build-on-ns3:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2
    - name: ns3 build
      uses: marshallasch/ns3-action@32.1
      with:
        location: 'contrib'
        sim_name: 'saf-example'
        sim_args: '--run-time=900 --total-nodes=5'

Special Thanks

I would like to acknowledge Dr. Jason Ernst (@compscidr) who gave me the idea to implement this pipeline stage to help validate that my simulation code actually builds.