Has it really been two months?! It’s like the quarter starts and I get sucked into a black hole, never to be heard from again. I’m starting to pick up Real World Haskell again, and I needed reliable documentation without relying on an internet connection, so I spun up a local Hoogle server as a systemd service.

Running Hoogle locally is nothing revolutionary. I followed some great sources. However, I did need more than a few sources, especially to get the systemd stuff worked out, so I’m writing everything down here so it’ll be in one place.

Edit: I was poking around in Twitter and I found my main source. It’s John Wiegley on Lost in Technopolis

  • Install hoogle and luakit.

    Pretty obvious, except we have a choice. We can install with cabal-install, but I prefer to use apt-get.

    luakit is not exactly required. You can just use your default browser (mine is Chromium), but I like using luakit in this context because I like having an icon and window for Hoogle separate from my main browser.

  • Create ~/.local/share/applications/hoogle.desktop.

    The hoogle.desktop file is a launcher for Linux GUIs that adhere to the Freedesktop.org standard, so you’ll have an icon in your applications menu and on your dock (where applicable).

; hoogle.desktop
[Desktop Entry]
Type=Application
Version=1.0
Name=Hoogle
Comment=A Haskell API search engine
Path=/usr/bin
Exec=/usr/bin/luakit http://localhost:1080
Icon=haskell
Terminal=false
Categories=Development;

  • Create ~/.icon tree.

    This part is just tedious. To make your life easier, I’ll provide a zip archive. Just unpack it and move the .icon directory to your home directory.

    This archive provides something of a minimal example for creating your own custom icons for Freedesktop.org-compliant environments, so you might peek inside to get an idea for how things work.

  • Create /etc/systemd/system/hoogle.service

    hoogle.service defines a system daemon that will run Hoogle in the background. We can enable it to run at boot, or we can manually start and stop the service as needed.

; hoogle.service
[Unit]
Description=A Haskell API search engine.
Documentation=man:hoogle(1)

[Service]
User=hoogle
ExecStart=/usr/bin/hoogle server --local --port 1080
WorkingDirectory=/var/log/hoogle

[Install]
WantedBy=multi-user.target

  • Create a system user called hoogle.

    We don’t want our Hoogle server running as root, so we’ll create a special non-login user.

# useradd -r hoogle
  • Create /var/log/hoogle and set ownership and mod rules.
# mkdir /var/log/hoogle
# chown hoogle:hoogle /var/log/hoogle
# chmod 775 /var/log/hoogle

  • Start and/or enable hoogle.service

    If you want the Hoogle daemon to run at system boot, replace <command> with enable. Using disable will undo this. If you want to manually start (res. stop) the Hoogle daemon, replace <command> with start (res. stop).

# systemctl <command> hoogle.service

And, that’s it. Once Hoogle is running as a daemon, you can use then find “Hoogle” in your GUI application launcher and launch it like any other app.