Environment variables done once

2-minute read
Ragnar Groot Koerkamp
devops linux wayland

Xrefs: GitHub issue

One problem I had with my Sway setup is that setting environment variables in my config.fish (the Fish equivalent to .bashrc or .zshrc) is not always sufficient.

In particular, I need my environment variables to be available in at least the following places:

  • my Fish shell,
  • applications launched from Sway (e.g. using keybindings),
  • applications launched as a systemd service (e.g. the Emacs server daemon).

Setting variables in the shell profile has the problem that they are not picked up by systemd services. Another option seems to be ~/.pam_environment, but this is deprecated.

One solution, coming from this GitHub issue, is to use environment.d provided by systemd, and import these variables into Sway:

  1. Create the directory ~/.config/environment.d/.

  2. Create one or more files containing variables. E.g. wayland.conf containing:

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    # Wayland configuration
GDK_BACKEND=wayland
XDG_SESSION_TYPE=wayland
SDL_VIDEO_DRIVER=wayland

  3. Instead of directly launching sway from your display manager or shell config, create a wrapper script swayrun.sh, based on this comment. You could put this in e.g. /usr/local/bin/ or somewhere in your homedir. This script calls a systemd generator to read all environment variables set in environment.d and exports them.

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    #!/usr/bin/env bash
set -euo pipefail

# Export all variables
set -a
# Call the systemd generator that reads all files in environment.d
source /dev/fd/0 <<EOF
$(/usr/lib/systemd/user-environment-generators/30-systemd-environment-d-generator)
EOF
set +a

exec sway

  4. In your display manager or shell config, replace exec sway by exec ~/path/to/swayrun.sh.

All your environment variables set in the environment.d directory will now be shared between your shell, Sway and systemd services.

Note that I am currently only using this setup on my laptop - not on my server. I am not exactly sure how well this would work when SSHing. Currently Fish inherits all environment variables from Sway and does not set any of them itself. This works fine without SSH, but you may need to source the environment.d generator script from Fish as well. Since Fish uses a somewhat different syntax from Bash and Zsh, this in itself is not completely trivial so I have not yet looked into this.