datastreamcorelib 1.3.0

Helpers and utilities for https://gitlab.com/advian-oss/python-datastreamservicelib that are not eventloop specific.

Core helpers and Abstract Base Classes for making use of ZMQ nice, easy and DRY.

You should probably look at https://gitlab.com/advian-oss/python-datastreamservicelib and https://gitlab.com/advian-oss/python-datastreamserviceapp_template unless you’re working on an adapter for yet unsupported eventloop.

Docker

For more controlled deployments and to get rid of “works on my computer” -syndrome, we always make sure our software works under docker.

It’s also a quick way to get started with a standard development environment.

SSH agent forwarding

We need buildkit:

export DOCKER_BUILDKIT=1

And also the exact way for forwarding agent to running instance is different on OSX:

export DOCKER_SSHAGENT="-v /run/host-services/ssh-auth.sock:/run/host-services/ssh-auth.sock -e SSH_AUTH_SOCK=/run/host-services/ssh-auth.sock"

and Linux:

export DOCKER_SSHAGENT="-v $SSH_AUTH_SOCK:$SSH_AUTH_SOCK -e SSH_AUTH_SOCK"

Creating a development container

Build image, create container and start it:

docker build --ssh default --target devel_shell -t datastreamcorelib:devel_shell .
docker create --name datastreamcorelib_devel -v `pwd`":/app" -it -v /tmp:/tmp `echo $DOCKER_SSHAGENT` datastreamcorelib:devel_shell
docker start -i datastreamcorelib_devel

pre-commit considerations

If working in Docker instead of native env you need to run the pre-commit checks in docker too:

docker exec -i datastreamcorelib_devel /bin/bash -c "pre-commit install"
docker exec -i datastreamcorelib_devel /bin/bash -c "pre-commit run --all-files"

You need to have the container running, see above. Or alternatively use the docker run syntax but using the running container is faster:

docker run -it --rm -v `pwd`":/app" datastreamcorelib:devel_shell -c "pre-commit run --all-files"

Test suite

You can use the devel shell to run py.test when doing development, for CI use the “tox” target in the Dockerfile:

docker build --ssh default --target tox -t datastreamcorelib:tox .
docker run -it --rm -v `pwd`":/app" `echo $DOCKER_SSHAGENT` datastreamcorelib:tox

Production docker

There’s a “production” target since it’s our standard pattern, however this library does not yet expose any CLI tools so the production target is kinda useless.

Local Development

TLDR:

• Create and activate a Python 3.6 virtualenv (assuming virtualenvwrapper):

  mkvirtualenv -p `which python3.6` my_virtualenv

• change to a branch:

  git checkout -b my_branch

• install Poetry: https://python-poetry.org/docs/#installation

• Install project deps and pre-commit hooks:

  poetry install
  pre-commit install
  pre-commit run --all-files

• Ready to go.

Use Python 3.6 for development since it’s the lowest supported version so you don’t accidentally use features only available in higher versions and then have to re-do everything when CI tests fail on 3.6.

Remember to activate your virtualenv whenever working on the repo, this is needed because pylint and mypy pre-commit hooks use the “system” python for now (because reasons).

Running “pre-commit run –all-files” and “py.test -v” regularly during development and especially before committing will save you some headache.