Make swarming bootstrap at boot, not login

skolo/raspberry-pi/setup-swarming.sh

Index: skolo/raspberry-pi/setup-swarming.sh
diff --git a/skolo/raspberry-pi/setup-swarming.sh b/skolo/raspberry-pi/setup-swarming.sh
index a30dd200c5c60d10711472802b3666f85db85cde..d081107297119941c6a8aeeb084297aa590c5d0e 100644
--- a/skolo/raspberry-pi/setup-swarming.sh
+++ b/skolo/raspberry-pi/setup-swarming.sh
@@ -1,8 +1,10 @@
 #!/bin/sh
-
-set -ex
 # Sets up the chrome-bot swarming user and installs python adb to /opt/adb
+
+set -ex
+
 sudo chroot /opt/raspberrypi/root/
+
 rm /etc/localtime
 ln -s /usr/share/zoneinfo/US/Eastern /etc/localtime
 
@@ -26,8 +28,8 @@ if [ ! -e /usr/include/openssl/opensslconf.h ]
 then
 	sudo ln -s /usr/include/arm-linux-gnueabihf/openssl/opensslconf.h /usr/include/openssl/opensslconf.h
 fi
-sudo pip install rsa
-sudo pip install libusb1
+pip install rsa

[stephana, 2016/04/29 13:18:41]

How does this work without sudo ? 
It might be viable approach to create a virtualenv for python-adb.

[kjlubick, 2016/04/29 13:53:05]

So, after the chroot (line 6) all subsequent commands are run as root.  I
believe swarming would need rsa/libusb1 as well. 

I am not familiar with virtualenvs.   What benefits would it yield us?

[stephana, 2016/04/29 17:30:58]

Virtual env would just isolate the Python installation. Essentially  you can
install anything into a virtual env. It limits the risk of having global
installs of python packages, but let's skip that until it becomes a real
problem. 

+pip install libusb1
 
 if [ ! -f /opt/adb ]
 then
@@ -35,5 +37,8 @@ then
 	./python-adb/make_tools.py
 	ln python-adb/adb.zip adb
 fi
+
+# Make swarming run on boot
+update-rc.d swarming defaults 90
 # Adb can now be used by python /opt/adb
 exit