Adding page for automating android app builds

Automating Android App Builds.wiki

@@ -0,0 +1,86 @@
+=Automated Android App Builds=
+
+Goal: Get a compiled apk of [[https://github.com/asteroidos/AsteroidOSSync|AsteroidOS Sync]] from the latest git commit.
+
+I wanted to do this without untracked software clutter on my main machine, so I decided to do it in a systemd-nspawn container on my home server. The container and build turned out better than I expected, so I went ahead with automating the whole setup to check daily for new commits, building the app if there is a new commit, and dumping it in a folder outside of the container.
+
+==Setting up systemd-nspawn==
+
+Arch makes this step super easy with the `arch-install-scripts` package:
+
+{{{class="prettyprint"
+# pacstrap -icd container/ base --ignore linux base-devel
+}}}
+
+* `-i`: Avoid auto-confirmation of package selections
+* `-c`: Use the package cache on the host rather than the target
+* `-d`: Allow installation to a non-mountpoint directory
+* `container/`: Path to your desired container location
+* `base --ignore linux base-devel`: Install the base and base-devel groups, ignoring the `linux` package. The kernel is not necessary inside this container, so might as well save the bandwidth
+
+This will get you a container with the latest packages ready to spin up. After that, all you need to do is:
+
+{{{class="prettyprint"
+# systemd-nspawn -bD container/
+}}}
+
+This will boot the container and leave you at a login prompt. For Arch, root will be passwordless. Start here, and configure your new container for what you need. For my setup, I created an unprivileged user, added my `~/.bashrc` and `~/.vimrc`, and installed the android-sdk package from the AUR.
+
+Next, we need to automate bringing the new container up with a systemd service. Easiest way to get a service ready for a systemd-nspawn is to use the existing systemd-nspawn@.service, and tweak it for this specific use. To get a copy of this unit and start editing it right away, run `systemctl edit --full systemd-nspawn@containername.service`. This is the end product of my unit:
+
+{{{class="prettyprint"
+# /etc/systemd/system/systemd-nspawn@asteroid.service
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+[Unit]
+Description=Container %i
+Documentation=man:systemd-nspawn(1)
+PartOf=machines.target
+Before=machines.target
+After=network.target
+
+[Service]
+ExecStart=/usr/bin/systemd-nspawn --quiet --keep-unit --boot --link-journal=try-guest -U --settings=override --machine=%i -D /storage/containers/asteroid/sync-app/ --bind=/storage/containers/asteroid/output:/home/thurstylark/output
+KillMode=mixed
+Type=notify
+RestartForceExitStatus=133
+SuccessExitStatus=133
+Slice=machine.slice
+Delegate=yes
+TasksMax=16384
+
+# Enforce a strict device policy, similar to the one nspawn configures
+# when it allocates its own scope unit. Make sure to keep these
+# policies in sync if you change them!
+DevicePolicy=closed
+DeviceAllow=/dev/net/tun rwm
+DeviceAllow=char-pts rw
+
+# nspawn itself needs access to /dev/loop-control and /dev/loop, to
+# implement the --image= option. Add these here, too.
+DeviceAllow=/dev/loop-control rw
+DeviceAllow=block-loop rw
+DeviceAllow=block-blkext rw
+
+[Install]
+WantedBy=machines.target
+}}}
+
+The only things changed from the original are all in `ExecStart=`:
+
+* `-D /storage/containers/asteroid/sync-app/`: Boot the nspawn from a directory instead of from an image, and the path to that directory
+* `--bind=/storage/containers/asteroid/output:/home/thurstylark/output`: Create a bind mount between the host and the container. The format is `/host/dir:/container/dir` where `/container/dir` is specified with `/` at the root of the container, not of the host.
+* Removed `--network-veth` to use the networking from the host instead of creating a virtual ethernet link. 
+
+Check the systemd-nspawn manpage for more info.
+
+===Reference===
+* https://wiki.archlinux.org/index.php/Systemd-nspawn
+
+----
+(wip)

index.wiki

@@ -5,6 +5,7 @@
 * [[Vimwiki]] -- This very wiki, and how it's hosted
 * [[Eudyptula Challenge]]
 * Cgit -- Configuration and hosting of [[https://git.thurstylark.com/|git.thurstylark.com]]
+* [[Automating Android App Builds]] -- Doccumentation of my setup for building AsteroidOS Sync from https://www.github.com/asteroidos/AsteroidOSSync
 
 === Reference ===