December 31, 2013
Skimmed from here , I mostly just changed the last line that starts Gunicorn from using gunicorn_django to plain gunicorn , as recommended by the Django overlords.
/etc/init/yourapp.conf:
description "Your App"
author "Your Name "
start on (net-device-up and local-filesystems)
stop on shutdown
respawn
script
export HOME="/root/of/django/app" # i.e. where "manage.py" can be found
export PATH="$PATH:/root/of/django/app/env/bin" # "env" is our virtualenv
export DJANGO_SETTINGS_MODULE="settings"
export LANG="en_US.UTF-8"
cd $HOME
exec $HOME/env/bin/gunicorn -b 127.0.0.1:8000 -w 1 --log-file /var/log/gunicorn/yourapp.log app
end script
app.py:
import os, sys
sys.path.insert(0, '/root/of/django/app/')
path = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
if path not in sys.path:
sys.path.append(path)
import django.core.handlers.wsgi
application = django.core.handlers.wsgi.WSGIHandler()
Tagged with: django gunicorn upstart
Categorised as: snippet
December 12, 2011 Setup being along the dev → test → prod lines, to correctly manage database migrations we first set things up at dev :
manage.py syncdb --noinput
manage.py convert_to_south <app>
manage.py createsuperuser
At this point the South migrations are being pushed to repository and pulled in at test :
manage.py syncdb --noinput
manage.py migrate
manage.py migrate <app> 0001 --fake
manage.py createsuperuser
Now, back at dev , after a change to one of the models:
manage.py schemamigration <app> --auto
manage.py migrate <app>
And, after push/pull, at test :
manage.py migrate <app> Tagged with: django south
Categorised as: snippet
October 23, 2011 Using Django and Tastypie , we automagically respond to SNS subscription requests. After that part is handled, the notification messages start coming in and those are used to trigger an SQS polling cycle (trying to do a thorough job there which may seem like an overkill but it's not). A received SQS message is parsed and contents are passed to an external program that forks and exits which keeps the request from blocking.
from django.conf import settings
from tastypie import fields, http
from tastypie.resources import Resource
from tastypie.bundle import Bundle
from tastypie.authentication import Authentication
from tastypie.authorization import Authorization
from tastypie.throttle import BaseThrottle
import boto.sq
from boto.sqs.message import Message
from urlparse import urlparse
import base64, httplib, tempfile, subprocess, time, json, os, sys, syslog
# Http://django-tastypie.readthedocs.org/en/latest/non_orm_data_sources.html
class NotificationObject(object):
def __init__(self, initial=None):
self.__dict__['_data'] = {}
if hasattr(initial, 'items'):
self.__dict__['_data'] = initial
def __getattr__(self, name):
return self._data.get(name, None)
def __setattr__(self, name, value):
self.__dict__['_data'][name] = value
class NotificationResource(Resource):
sns_messageid = fields.CharField(attribute='MessageId')
sns_timestamp = fields.CharField(attribute='Timestamp')
sns_topicarn = fields.CharField(attribute='TopicArn')
sns_type = fields.CharField(attribute='Type')
sns_unsubscribeurl = fields.CharField(attribute='UnsubscribeURL')
sns_subscribeurl = fields.CharField(attribute='SubscribeURL')
sns_token = fields.CharField(attribute='Token')
sns_message = fields.CharField(attribute='Message')
sns_subject = fields.CharField(attribute='Subject')
sns_signature = fields.CharField(attribute='Signature')
sns_signatureversion = fields.CharField(attribute='SignatureVersion')
sns_signingcerturl = fields.CharField(attribute='SigningCertURL')
class Meta:
resource_name = 'notification'
object_class = NotificationObject
fields = ['sns_messageid']
list_allowed_methods = ['post']
authentication = Authentication()
authorization = Authorization()
def get_resource_uri(self, bundle_or_obj):
return ''
def obj_create(self, bundle, request=None, **kwargs):
bundle.obj = NotificationObject(initial={ 'MessageId': '', 'Timestamp': '', 'TopicArn': '', 'Type': '', 'UnsubscribeURL': '', 'SubscribeURL': '', 'Token': '', 'Message': '', 'Subject': '', 'Signature': '', 'SignatureVersion': '', 'SigningCertURL': '' })
bundle = self.full_hydrate(bundle)
o = urlparse(bundle.data['SigningCertURL'])
if not o.hostname.endswith('.amazonaws.com'):
return bundle
topicarn = bundle.data['TopicArn']
if topicarn != settings.SNS_TOPIC:
return bundle
if not self.verify_message(bundle):
return bundle
if bundle.data['Type'] == 'SubscriptionConfirmation':
self.process_subscription(bundle)
elif bundle.data['Type'] == 'Notification':
self.process_notification(bundle)
return bundle
def process_subscription(self, bundle):
syslog.syslog('SNS Subscription ' + bundle.data['SubscribeURL'])
o = urlparse(bundle.data['SubscribeURL'])
conn = httplib.HTTPSConnection(o.hostname)
conn.putrequest('GET', o.path + '?' + o.query)
conn.endheaders()
response = conn.getresponse()
subscription = response.read()
def process_notification(self, bundle):
sqs = boto.sqs.connect_to_region(settings.SQS_REGION)
queue = sqs.lookup(settings.SQS_QUEUE)
retries = 5
done = False
while True:
if retries < 1:
break
retries -= 1
time.sleep(5)
messages = queue.get_messages(10, visibility_timeout=60)
if len(messages) < 1:
continue
for message in messages:
try:
m = json.loads(message.get_body())
m['return_sns_region'] = settings.SNS_REGION
m['return_sns_topic'] = settings.SNS_TOPIC
m['return_sqs_region'] = settings.SQS_REGION
m['return_sqs_queue'] = settings.SQS_QUEUE
process = subprocess.Popen(['/usr/bin/nice', '-n', '15', os.path.dirname(os.path.normpath(os.sys.modules[settings.SETTINGS_MODULE].__file__)) + '/process.py', base64.b64encode(json.dumps(m))], shell=False)
process.wait()
except:
e = sys.exc_info()[1]
syslog.syslog(str(e))
queue.delete_message(message)
def verify_message(self, bundle):
message = u''
if bundle.data['Type'] == 'SubscriptionConfirmation':
message += 'Message\n'
message += bundle.data['Message'] + '\n'
message += 'MessageId\n'
message += bundle.data['MessageId'] + '\n'
message += 'SubscribeURL\n'
message += bundle.data['SubscribeURL'] + '\n'
message += 'Timestamp\n'
message += bundle.data['Timestamp'] + '\n'
message += 'Token\n'
message += bundle.data['Token'] + '\n'
message += 'TopicArn\n'
message += bundle.data['TopicArn'] + '\n'
message += 'Type\n'
message += bundle.data['Type'] + '\n'
elif bundle.data['Type'] == 'Notification':
message += 'Message\n'
message += bundle.data['Message'] + '\n'
message += 'MessageId\n'
message += bundle.data['MessageId'] + '\n'
if bundle.data['Subject'] != '':
message += 'Subject\n'
message += bundle.data['Subject'] + '\n'
message += 'Timestamp\n'
message += bundle.data['Timestamp'] + '\n'
message += 'TopicArn\n'
message += bundle.data['TopicArn'] + '\n'
message += 'Type\n'
message += bundle.data['Type'] + '\n'
else:
return False
o = urlparse(bundle.data['SigningCertURL'])
conn = httplib.HTTPSConnection(o.hostname)
conn.putrequest('GET', o.path)
conn.endheaders()
response = conn.getresponse()
cert = response.read()
# ok; attempt to use m2crypto failed, using openssl command line tool instead
file_cert = tempfile.NamedTemporaryFile(mode='w', delete=False)
file_sig = tempfile.NamedTemporaryFile(mode='w', delete=False)
file_mess = tempfile.NamedTemporaryFile(mode='w', delete=False)
file_cert.write(cert)
file_sig.write(bundle.data['Signature'])
file_mess.write(message)
file_cert.close()
file_sig.close()
file_mess.close()
# see: https://async.fi/2011/10/sns-verify-sh/
verify_process = subprocess.Popen(['/usr/local/bin/sns-verify.sh', file_cert.name, file_sig.name, file_mess.name], shell=False)
verify_process.wait()
if verify_process.returncode == 0:
return True
return False
That process.py would be something like:
#!/usr/bin/env python
import boto.sqs
from boto.sqs.message import Message
import base64, json, os, sys, syslog
if len(sys.argv) != 2:
sys.exit('usage: %s <base64 encoded json object>' % (sys.argv[0], ))
m = json.loads(base64.b64decode(sys.argv[1]))
# http://code.activestate.com/recipes/66012-fork-a-daemon-process-on-unix/
try:
pid = os.fork()
if pid > 0:
sys.exit(0)
except OSError, e:
print >>sys.stderr, "fork #1 failed: %d (%s)" % (e.errno, e.strerror)
sys.exit(1)
os.chdir("/")
os.setsid()
os.umask(0)
try:
pid = os.fork()
if pid > 0:
sys.exit(0)
except OSError, e:
sys.exit(1)
syslog.syslog(sys.argv[0] + ': ' + str(m))
# ...
That is, process.py gets the received (and doped) SQS message, Base64 encoded, as it's only command line argument, forks, exits and does what it's supposed to do after that on its own. Control returns to NotificationResource so the request doesn't block unnecessarily.
Tagged with: aws django python rest sns sqs tastypie
Categorised as: snippet
October 16, 2011
# http://aws.amazon.com/articles/1434
def S3UploadParams(bucket_name, object_name, expiry, maxsize, redirect):
import os, boto, json, base64, hmac, hashlib
from time import time, gmtime, strftime
def SignS3Upload(policy_document):
policy = base64.b64encode(policy_document)
return base64.b64encode(hmac.new(
boto.config.get('Credentials', 'aws_secret_access_key'),
policy,
hashlib.sha1
).digest())
def GenerateS3PolicyString(bucket_name, object_name, expiry, maxsize, redirect):
policy_template = '{ "expiration": "%s", "conditions": [ {"bucket": "%s"}, ["eq", "$key", "%s"], {"acl": "private"}, {"success_action_redirect": "%s"}, ["content-length-range", 0, %s] ] }'
return policy_template % (
strftime("%Y-%m-%dT%H:%M:%SZ", gmtime(time() + expiry)),
bucket_name,
object_name,
redirect,
maxsize
)
params = {
'key': object_name,
'AWSAccessKeyId': boto.config.get('Credentials', 'aws_access_key_id'),
'acl': 'private',
'success_action_redirect': redirect,
}
policy = GenerateS3PolicyString(bucket_name, object_name, expiry, maxsize, redirect)
params['policy'] = base64.b64encode(policy)
signature = SignS3Upload(policy)
params['signature'] = signature
return params
Tagged with: aws django http post python s3
Categorised as: snippet