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direnv

We generally prepare two things with direnv:

  • A Nix devShell containing any development dependencies of the application.
  • Environment variables, some of which may come from secure storage.

Prerequisites​

Sample configuration​

direnv invokes bash with its own standard library of additional functions, so any valid bash is valid direnv configuration.

warning

Since developers may choose to customise their configurations beyond what the authors intended, we do not write our configurations to .envrc directly, instead writing them to sample.envrc.

Developers may either link or copy this file to .envrc, and the path is ignored by source control to avoid their customisations being overwritten or accidentally checked in.

Loading a Nix devShell​

We use the git+ssh scheme over github: to avoid the need for GitHub tokens in your Nix daemon configuration. Note the ${name} and ${version} placeholders, which you'll need to replace with the name of the desired shell. You can find these documented in throwparty/nix: shells/default.nix@main

use flake "git+ssh://git@github.com/throwparty/nix#${name}_${version}"

Setting environment variables from secrets​

$creds isn't exported, so it won't be copied into the shell direnv spawns. Since $SOME_APP_USER and $SOME_APP_TOKEN are, they will.

# Some app credentials
creds="$(bw get item 'throwparty/sample-app')"
export SOME_APP_USER="$(echo "$creds" | jq -r '.fields[] | select(.name == "Some app user") | .value')"
export SOME_APP_TOKEN="$(echo "$creds" | jq -r '.fields[] | select(.name == "Some app token") | .value')"