Pedantic Elixir Builds

Setting up pedantic Elixir builds in 2019

1. Pedantic Elixir Builds Andrew Summers 2019-01-23
3. Who? • Backend Software Engineer at albert.io • Wrote Dialyzer pretty printer • Maintainer of Dialyxir, Erlex, elixir-lsp packages • Contributor to many others!
4. What? • Set up CI with pedantic builds • Recipe for contributing to open source • Improve code quality at work using tools
5. How? • Turn on all current tooling to maximum pedantry • Add extra checks according to your team's conventions • Set up continuous integration every build using e.g. Travis, Circle CI, Jenkins • Reject pull requests that do not satisfy all checks
6. • Travis (Continuous Integration) • Compiler (warnings as errors) • Formatter • Credo (linter) • ExUnit (tests) • Dialyzer (type checker) • Sobelow (security)
7. • Good first PR to fix warnings and prevent them in future • Surprising how many open source projects have errors! mix compile --warnings-as-errors
8. • Elixir 1.6+ • Consistent code in ecosystem mix format --check-formatted
9. • Elixir linter • Turn on as many optional rules as you can handle • Add your own rules to e.g. enforce defp type specs mix credo list --strict
10. • Write more tests, you don't have enough. • Consider property testing mix test
11. • Erlang type checker, sometimes lies • Full PLT analysis cache rebuild on Elixir, Erlang version change, partial rebuild on dependency changes mix dialyzer --halt-exit-status
12. • Security analysis tool • Scans for e.g. String.to_atom/1, SQL injection mix sobelow --exit low
13. Other tools • coveralls, via ExCoveralls for coverage analysis • dependabot for keeping dependencies up to date • inch for documentation analysis
14. • https://bit.ly/2Mumw25 •
15. asummers _asummers Thanks!