That should do it. But like I said, my understanding of the system is very limited and I'm sure there are cases when this simplistic pattern just won't cut it. My needs, however, at the moment are not the most complicated.
If Foo is definitely defined, then this is most likely a circular import which can be avoided by dropping the "redundant" import statement and referring not directly to the Model itself, but its' name. This is known as a lazy relationship:
(Ouch! Looks like WordPress update to 3.1.3 wiped all the modifications I made to the default theme. Admittedly I should've seen that coming.)
What I want to do is basically attach a key-value pair to an EC2 instance when launching it in AWS Management Console and read the value inside the instance when it's running. To be more specific, I use this to to set a key called environment that can have values like dev, stage and prod so that the Django config can decide which database to connect to etc. while starting up. I suspect that in Boto the current instance can somehow be referenced in a more direct fashion but this works as well.
First, append the following to /etc/profile:
# See: http://stackoverflow.com/questions/625644/find-out-the-instance-id-from-within-an-ec2-machine
export EC2_INSTANCE_ID="`wget -q -O - http://169.254.169.254/latest/meta-data/instance-id || die \"wget instance-id has failed: $?\"`"
test -n "$EC2_INSTANCE_ID" || die 'cannot obtain instance-id'
export EC2_AVAIL_ZONE="`wget -q -O - http://169.254.169.254/latest/meta-data/placement/availability-zone || die \"wget availability-zone has failed: $?\"`"
test -n "$EC2_AVAIL_ZONE" || die 'cannot obtain availability-zone'
export EC2_REGION="`echo \"$EC2_AVAIL_ZONE\" | sed -e 's:\\([0-9][0-9]*\\)[a-z]*\\$:\\\\1:'`"
Now we know the region and instance ID. Next, install Boto by running the following commands:
zcat boto-2.0b4.tar.gz | tar xfv -
python ./setup.py install
from boto import ec2
ec2_instance_id = os.environ.get('EC2_INSTANCE_ID')
ec2_region = os.environ.get('EC2_REGION')
conn = ec2.connect_to_region(ec2_region)
reservations = conn.get_all_instances()
instances = [i for r in reservations for i in r.instances]
for instance in instances:
if instance.__dict__['id'] == ec2_instance_id: