This chapter will get you started with MSS development.

MSS is written in Python.

Once a stable release is published we do only bug fixes in stable and release regulary new minor versions. If a fix needs a API change or it is likly more a new feature you have to make a pull request to the develop branch. Documentation of changes is done by using our issue tracker.

When it is ready the developer version becomes the next stable.

Style guide

We generally follow pep8, with 120 columns instead of 79.

Output and Logging

When writing logger calls, always use correct log level (debug only for debugging, info for informative messages, warning for warnings, error for errors, critical for critical errors/states).

Building a development environment

If you want to contribute make a fork on bitbucket of mss. For building you have to use the conda recipe localy and install in a new environment.

Some of used packages are in the conda-forge channel located, so we have to add this channel to the default:

$ conda config --add channels conda-forge

Or add the channel by an editor to the .condarc config file:

$ more ~/.condarc
- defaults
- conda-forge

using a local meta.yaml recipe:

$ git clone
$ cd mss
$ conda create -n mssdev python=3
$ conda activate mssdev
$ conda build .
$ conda install --use-local mss
$ mkdir "$HOME/.config/mss"
$ # cp mss_settings.json.sample to "$HOME/.config/mss/mss_settings.json"
$ conda remove mss

alternative get the whole package first:

$ conda create -n mssdev mss
$ conda activate mssdev
$ conda remove mss

Compare versions used in the meta.yaml between stable and develop branch and apply needed changes.

Add the path of your local cloned mss directory to $PYTHONPATH.

Add developer packages for running tests, activate your env and run:

$ conda install --file requirements.d/development.txt

On linux install xvfb from your linux package manager. This is used to run tests on a virtual display.

Setup demodata

Simulated Data and its configuration is provided by executing:

$(mssdev) python mslib/mswms/

To use this data add the in your python path:

$(mssdev) :~/PycharmProjects/mss
$(mssdev) export PYTHONPATH="`pwd`:~/mss"
$(mssdev) python mslib/mswms/

Running tests

We have implemented demodata as data base for testing. On first call of pytest a set of demodata becomes stored in a /tmp/mss* folder. If you have installed gitpython a postfix of the revision head is added.

$ pytest

Use the -v option to get a verbose result. By the -k option you could select one test to execute only.

A pep8 only test is done by py.test –pep8 -m pep8 or pytest –pep8 -m pep8

Instead of running a ibrary module as a script by the -m option you may also use the pytest command.

$ pytest --cov mslib

This plugin produces a coverage report, example:

----------- coverage: platform linux, python 3.7.3-final-0 -----------
Name                                     Stmts   Miss Branch BrPart  Cover
mslib/                            2      0      0      0   100%
mslib/msui/                      23      0      0      0   100%
mslib/msui/                     52      1      8      1    97%
mslib/msui/                     12      2      4      2    75%
mslib/msui/                  383    117    141     16    66%

Profiling can be done by e.g.:

$ python -m cProfile  -s time ./mslib/mswms/ > profile.txt


/!\ existing server config: "" for demodata not overwritten!

To use this setup you need the in your python path e.g.
export PYTHONPATH=~/mss
         398119 function calls (389340 primitive calls) in 0.834 seconds

   Ordered by: internal time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
       19    0.124    0.007    0.496    0.026
       19    0.099    0.005    0.099    0.005 {method 'close' of 'netCDF4._netCDF4.Dataset' objects}

Setup mss_settings.json

On default all tests use default configuration defined in mslib.msui.MissionSupportSystemDefaultConfig. If you want to overwrite this setup and try out a special configuration add an mss_settings.json file to the testings base dir in your tmp directory.

Building the docs with Sphinx

The documentation (in reStructuredText format, .rst) is in docs/.

To build the html version of it, you need to have sphinx installed:

cd docs/
make html

Then point a web browser at docs/_build/html/index.html.

Update local stable branch

If you don’t have a stable branch, create one first or change to that branch:

git checkout [-b] stable
git pull stable
git push

Merging stable into develop

Bug fixes we have done in stable we need to merge regulary into develop too:

git checkout stable
git pull
git checkout develop
git pull
git merge stable

Creating a new release

  • make sure all issues for this milestone are closed or moved to the next milestone

  • update CHANGES.rst, based on git log

  • check version number of upcoming release in CHANGES.rst

  • verify that, meta.yaml, and are complete

  • for a new stable release merge from develop to stable

  • tag the release:

    git tag -s -m "tagged/signed release X.Y.Z" X.Y.Z
    git push origin X.Y.Z
  • create a release on anaconda conda-forge

  • announce on:

  • Mailing list

  • Twitter (follow @ReimarBauer for these tweets)