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Python Flask Server MQTT can't interact with socket.io

Server:
Ubuntu 18.04.3 LTS
python3.6
I want show device's message on web, my structure like:
Device--(MQTT)-->Server--(socket.io)-->Web
First, I publish message by mqtt to Server, and Server successed subscribed to get message .
Second, I use socket.io to send message to Web, but problem is here, if Server send message by socket.io after mqtt.on_message, the web's socket.io will be stuck, until refresh web.
My Flask Server a part of code:
from flask import Flask, request, render_template, flash, redirect, url_for
from flask_mqtt import Mqtt
from flask_socketio import SocketIO
from flask_bootstrap import Bootstrap
from flask_login import UserMixin, LoginManager, login_required, current_user, login_user, login_required, logout_user
from flask_sqlalchemy import SQLAlchemy
from flask_bcrypt import Bcrypt
from forms import RegisterForm, LoginForm, AddForm, ChangePasswordForm
import pymysql
from config import Config
from sqlalchemy.ext.declarative import declarative_base
import json
import plotly as py
from datetime import datetime
import eventlet
eventlet.monkey_patch()
# MQTT
app = Flask(__name__)
bcrypt = Bcrypt(app)
app.config['SECRET'] = ''
app.config['TEMPLATES_AUTO_RELOAD'] = True
app.config['MQTT_BROKER_URL'] = ''
app.config['MQTT_BROKER_PORT'] =
app.config['MQTT_USERNAME'] = ''
app.config['MQTT_PASSWORD'] = ''
app.config['MQTT_KEEPALIVE'] = 5
app.config['MQTT_TLS_ENABLED'] = False
app.config['SQLALCHEMY_DATABASE_URI'] = ''
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
mqtt = Mqtt(app)
socketio = SocketIO(app, cors_allowed_origins='*')
if __name__ == '__main__':
socketio.run(app, keyfile='privkey.pem', certfile='fullchain.pem', host='0.0.0.0', port=5002, use_reloader=True, debug=True)
Flask Server MQTT and socket.io part of code:
#mqtt.on_connect()
def handle_connect(client, userdata, flags, rc):
mqtt.subscribe('test')
#mqtt.on_message()
def handle_mqtt_message(client, userdata, message):
topic = message.topic,
raw_payload = message.payload.decode()
if(topic[0] == "test"):
socketio.emit('web', "received")
Web Client javascript code:
socket.on('web', function(data) {
console.log(data);
})
If just use socket.io to send message to web didn't use mqtt it's work fine. I don't know why they can't interact together. Then I find something on flask-mqtt offical file about "MQTT Interact with SocketIO", example code the difference from me is "import eventlet". So i guess is abotu threading problem? But when i also import it will show error, the error is:
Traceback (most recent call last):
File "/usr/local/lib/python3.6/dist-packages/eventlet/hubs/hub.py", line 461, in fire_timers
timer()
File "/usr/local/lib/python3.6/dist-packages/eventlet/hubs/timer.py", line 59, in __call__
cb(*args, **kw)
File "/usr/local/lib/python3.6/dist-packages/eventlet/greenthread.py", line 221, in main
result = function(*args, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/eventlet/wsgi.py", line 818, in process_request
proto.__init__(conn_state, self)
File "/usr/local/lib/python3.6/dist-packages/eventlet/wsgi.py", line 357, in __init__
self.handle()
File "/usr/local/lib/python3.6/dist-packages/eventlet/wsgi.py", line 390, in handle
self.handle_one_request()
File "/usr/local/lib/python3.6/dist-packages/eventlet/wsgi.py", line 419, in handle_one_request
self.raw_requestline = self._read_request_line()
File "/usr/local/lib/python3.6/dist-packages/eventlet/wsgi.py", line 402, in _read_request_line
return self.rfile.readline(self.server.url_length_limit)
File "/usr/lib/python3.6/socket.py", line 586, in readinto
return self._sock.recv_into(b)
File "/usr/local/lib/python3.6/dist-packages/eventlet/green/ssl.py", line 241, in recv_into
return self._base_recv(nbytes, flags, into=True, buffer_=buffer)
File "/usr/local/lib/python3.6/dist-packages/eventlet/green/ssl.py", line 256, in _base_recv
read = self.read(nbytes, buffer_)
File "/usr/local/lib/python3.6/dist-packages/eventlet/green/ssl.py", line 176, in read
super(GreenSSLSocket, self).read, *args, **kwargs)
File "/usr/local/lib/python3.6/dist-packages/eventlet/green/ssl.py", line 146, in _call_trampolining
return func(*a, **kw)
File "/usr/lib/python3.6/ssl.py", line 874, in read
return self._sslobj.read(len, buffer)
File "/usr/lib/python3.6/ssl.py", line 631, in read
v = self._sslobj.read(len, buffer)
ssl.SSLWantReadError: The operation did not complete (read) (_ssl.c:2309)
I searched about this error, some result say this is eventlet's Bug on python3, Is any solution for this error?

Tornado authenticating to MongoDB using Motor

I made a tornado app that is supposed to run some queries against a mongodb instance running on another machine. To this purpose I have set up mongodb with authentication and users. I have checked that everything works and that I can authenticate to tornado using the Robo 3T app and a small synchronous script that uses pymongo.
This is how I initialize my tornado application:
class API(tornado.web.Application):
def __init__(self):
settings = dict(
autoreload=True,
compiled_template_cache=False,
static_hash_cache=False,
serve_traceback=True,
cookie_secret="secret",
xsrf_cookies=True,
static_path=os.path.join(os.path.dirname(__file__), "media"),
template_loader=tornado.template.Loader('./templates')
)
mongohost = os.environ.get('MONGOHOST', 'localhost')
mongoport = os.environ.get('MONGOPORT', 27017)
mongouser = os.environ.get('MONGOUSER')
mongopass = os.environ.get('MONGOPASS')
mongodb = os.environ.get('MONGODB')
mongouri = f'mongodb://{mongouser}:{mongopass}#{mongohost}:{mongoport}/{mongodb}'
self.client = motor.motor_tornado.MotorClient(mongouri)
logging.info('connected to mongodb')
self.db = self.client.get_default_database()
logging.info('got mongodb database')
tornado.web.Application.__init__(self, url_patterns, **settings)
def main():
port = 8888
FORMAT = ('%(asctime)s %(levelname) -10s %(name) -30s %(funcName) -35s %(lineno) -5d: %(message)s')
logging.basicConfig(level=logging.DEBUG, format=FORMAT)
tornado.ioloop.IOLoop.configure(TornadoUvloop)
app = API()
app.listen(port)
signal.signal(signal.SIGINT, sig_exit)
logging.info('Tornado server started on port %s' % port)
tornado.ioloop.IOLoop.instance().start()
if __name__ == "__main__":
main()
Everything appears to run until one of my handlers that actually performs queries against the database is hit. Code from the handler looks like this:
cursor = self.application.db['events'].find(
find,
projection
).limit(perpage).skip(page*perpage)
buffsize = 0
try:
while (yield cursor.fetch_next):
message = cursor.next_object()
self.write(json.dumps(message, default=json_util.default))
buffsize += 1
if buffsize >= 10:
buffsize = 0
yield self.flush()
yield self.flush()
except Exception:
logging.error('Could not connect to mongodb', exc_info=True)
This code worked just fine before trying to use authentication but now it raises exceptions and stoped working:
017-12-12 13:00:20,718 INFO root __init__ 37 : connected to mongodb
2017-12-12 13:00:20,718 INFO root __init__ 39 : got mongodb database
2017-12-12 13:00:20,723 INFO root main 67 : Tornado server started on port 8888
2017-12-12 13:00:25,226 INFO tornado.general _check_file 198 : /Users/liviu/Documents/Work/api_v2/src/api_tmp/handlers/event_list.py modified; restarting server
2017-12-12 13:00:25,469 INFO root __init__ 37 : connected to mongodb
2017-12-12 13:00:25,469 INFO root __init__ 39 : got mongodb database
2017-12-12 13:00:25,472 INFO root main 67 : Tornado server started on port 8888
2017-12-12 13:00:28,152 INFO root get 266 : now querying database
2017-12-12 13:00:28,214 ERROR root get 355 : Could not connect to mongodb
Traceback (most recent call last):
File "/Users/liviu/Documents/Work/api_v2/src/api_tmp/handlers/event_list.py", line 346, in get
while (yield cursor.fetch_next):
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/tornado/gen.py", line 1055, in run
value = future.result()
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/tornado/concurrent.py", line 238, in result
raise_exc_info(self._exc_info)
File "<string>", line 4, in raise_exc_info
File "/usr/local/Cellar/python3/3.6.3/Frameworks/Python.framework/Versions/3.6/lib/python3.6/concurrent/futures/thread.py", line 56, in run
result = self.fn(*self.args, **self.kwargs)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/cursor.py", line 1055, in _refresh
self.__collation))
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/cursor.py", line 892, in __send_message
**kwargs)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/mongo_client.py", line 950, in _send_message_with_response
exhaust)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/mongo_client.py", line 961, in _reset_on_error
return func(*args, **kwargs)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/server.py", line 99, in send_message_with_response
with self.get_socket(all_credentials, exhaust) as sock_info:
File "/usr/local/Cellar/python3/3.6.3/Frameworks/Python.framework/Versions/3.6/lib/python3.6/contextlib.py", line 81, in __enter__
return next(self.gen)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/server.py", line 168, in get_socket
with self.pool.get_socket(all_credentials, checkout) as sock_info:
File "/usr/local/Cellar/python3/3.6.3/Frameworks/Python.framework/Versions/3.6/lib/python3.6/contextlib.py", line 81, in __enter__
return next(self.gen)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/pool.py", line 852, in get_socket
sock_info.check_auth(all_credentials)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/pool.py", line 570, in check_auth
auth.authenticate(credentials, self)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/auth.py", line 486, in authenticate
auth_func(credentials, sock_info)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/auth.py", line 466, in _authenticate_default
return _authenticate_scram_sha1(credentials, sock_info)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/auth.py", line 209, in _authenticate_scram_sha1
res = sock_info.command(source, cmd)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/pool.py", line 477, in command
collation=collation)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/network.py", line 116, in command
parse_write_concern_error=parse_write_concern_error)
File "/Users/liviu/.venv/api/lib/python3.6/site-packages/pymongo/helpers.py", line 210, in _check_command_response
raise OperationFailure(msg % errmsg, code, response)
pymongo.errors.OperationFailure: Authentication failed.
2017-12-12 13:00:28,220 INFO tornado.access log_request 2063: 200 GET /event/list/web?starttime=2017-01-01&endtime=2017-02-03T14:00:00&minlatitude=10&maxlatitude=20&minlongitude=10&maxlongitude=20&minmagnitude=2&maxmagnitude=5&mindepth=10&maxdepth=100 (::1) 67.88ms
I was able to find some simple examples on how to log in and authenticate to MongoDB and as far as I can figure, that is exactly how I am also doing it (https://github.com/mongodb/motor/blob/master/doc/examples/authentication.rst).
Can anybody shed some light on what is going on and how to properly authenticate to MongoDB from an actual working tornado application using Motor?
P.S. I am using Python 3.6, tornado 4.5.2 and motor 1.1.
P.P.S. In the meantime I have discovered that using this as the uri makes it work properly:
mongouri = f'mongodb://{mongouser}:{mongopass}#{mongohost}:{mongoport}/admin'
In the above, I replaced {mongodb} with the "admin" db. After the client gets connected and authenticated on the admin database, I can proceed to get_database(mongodb) and it will work properly. If anyone cares to more clearly articulate what is going on I will accept the answer.

From the mongodb docs :
authSource
Specify the database name associated with the user’s credentials.
authSource defaults to the database specified in the connection
string.
That explains why it works if you specify "admin" as target database.
So in your case you should use:
mongouri = f'mongodb://{mongouser}:{mongopass}#{mongohost}:{mongoport}/{mongodb}?authSource=admin'

Flask_MongoEngine doesn't work on Webfaction?

I'm currently trying to deploy a website built with the Python Flask framework to Webfaction. I've deployed a MongoDB to which I can succesfully connect from the MongoDB interactive interpreter:
[celli#web498 ~]$ mongo localhost:18209/admin
MongoDB shell version: 3.0.2
connecting to: localhost:18209/admin
> db.auth("awesomeusername", "anawesomepassword")
1
When starting the website, it can successfully connect using these credentials in my flask config.py file:
MONGODB_SETTINGS = {
'db': 'tc',
'port': 18209,
'username': 'awesomeusername',
'password': 'anawesomepassword',
}
But when I visit a page which does a query I get the error below. This code works perfectly well on another server, so the mistake lies somewhere in either the setup of my MongoDB instance, or in the connection to it. I also find it strange that setting up the connection works fine, but querying it creates this Authentication failed error.
Any idea how I can fix this? All tips are welcome!
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/flask_login.py", line 758, in decorated_view
return func(*args, **kwargs)
File "/home/celli/webapps/tc/tc/app/views/webviews.py", line 220, in myTickets
userDocs = UserDocument.objects(id__in=[ticket.doc_id for ticket in userTickets])
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/mongoengine/queryset/manager.py", line 37, in __get__
queryset = queryset_class(owner, owner._get_collection())
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/mongoengine/document.py", line 168, in _get_collection
db = cls._get_db()
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/mongoengine/document.py", line 162, in _get_db
return get_db(cls._meta.get("db_alias", DEFAULT_CONNECTION_NAME))
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/mongoengine/connection.py", line 143, in get_db
source=conn_settings['authentication_source'])
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/pymongo/database.py", line 978, in authenticate
self.connection._cache_credentials(self.name, credentials)
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/pymongo/mongo_client.py", line 467, in _cache_credentials
auth.authenticate(credentials, sock_info, self.__simple_command)
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/pymongo/auth.py", line 475, in authenticate
auth_func(credentials[1:], sock_info, cmd_func)
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/pymongo/auth.py", line 450, in _authenticate_default
return _authenticate_scram_sha1(credentials, sock_info, cmd_func)
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/pymongo/auth.py", line 238, in _authenticate_scram_sha1
sasl_start, sasl_continue)
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/pymongo/auth.py", line 185, in _scram_sha1_conversation
res, _ = cmd_func(sock_info, source, sasl_start)
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/pymongo/mongo_client.py", line 703, in __simple_command
helpers._check_command_response(response, None, msg)
File "/home/celli/webapps/tc/venv/lib/python2.7/site-packages/pymongo/helpers.py", line 182, in _check_command_response
raise OperationFailure(msg % errmsg, code, response)
OperationFailure: command SON([('saslStart', 1), ('mechanism', 'SCRAM-SHA-1'), ('autoAuthorize', 1), ('payload', Binary('n,,n=awesomeusername,r=NjAxNTEwMjc5MzAy', 0))]) on namespace tc.$cmd failed: Authentication failed.

MongoDB's users are per-database. In your example you show that you connect to the admin database, but the error message is simply telling you that your user is trying to authenticate with the tc database. Probably your user doesn't have a role on tc.
(The other possibility is that tc is not the database you want to connect to; you need to specify the correct database name in your connection params/string).

Python Pymongo auth failed

Pymongo keep failing to login MongoDB. I typed right password for "root" account.
Traceback (most recent call last):
File "index.py", line 3, in <module>
from apis import app
File "/home/app/apis/__init__.py", line 16, in <module>
import apis.call
File "/home/app/apis/call.py", line 12, in <module>
import auth
File "/home/app/apis/auth.py", line 18, in <module>
connection.api.authenticate(database.ADMIN_ID,database.ADMIN_PASSWD)
File "/usr/lib64/python2.6/site-packages/pymongo/database.py", line 875, in authenticate
self.connection._cache_credentials(self.name, credentials)
File "/usr/lib64/python2.6/site-packages/pymongo/mongo_client.py", line 456, in _cache_credentials
auth.authenticate(credentials, sock_info, self.__simple_command)
File "/usr/lib64/python2.6/site-packages/pymongo/auth.py", line 243, in authenticate
auth_func(credentials[1:], sock_info, cmd_func)
File "/usr/lib64/python2.6/site-packages/pymongo/auth.py", line 222, in _authenticate_mongo_cr
cmd_func(sock_info, source, query)
File "/usr/lib64/python2.6/site-packages/pymongo/mongo_client.py", line 687, in __simple_command
helpers._check_command_response(response, None, msg)
File "/usr/lib64/python2.6/site-packages/pymongo/helpers.py", line 178, in _check_command_response
raise OperationFailure(msg % errmsg, code, response)
pymongo.errors.OperationFailure: command SON([('authenticate', 1), ('user', u'root'), ('nonce', u'9e44852e6597a1de'), ('key', u'f132369d21874c9858409e235abff25f')]) failed: auth failed
Here is pymongo
import pymongo
connection = pymongo.MongoClient("127.0.0.1")
connection.api.authenticate("root","1234")
db = connection.api
does pymongo use md5 on password? it looks like there is some different password in mongodb data.
here is mongodb admin system.users data
{
"user": "root",
"pwd": "cde0d84e6749c235a3b4e36d945eb6fe",
"roles": [
"userAdminAnyDatabase"
]
}
Do you see what is wrong?

In my case, I upgraded pymongo
pip install --upgrade pymongo

I tried to connect table called api.
connection.api.authenticate("root","1234")
There wasn't admin account in api table. I did put in system.admin table. So, I created a new admin account in api table and it worked.

Looks like you have to cut the certificate from the Bluemix MongoDB Credentials, save in a file (e.g. certificate.pem), and refer to it as follows:
client = pymongo.MongoClient(uri_string, ssl_ca_certs='c:\data\certificate.pem')

Using SQLAlchemy on App Engine development server

I have seen some questions about using SQLAlchemy on App Engine to connect to Google Cloud SQL. But I'm not sure if it is possible to develop using a local MySQL database and the existing SQLAlchemy dialect. On my first attempt, I added SQLAlchemy 0.8.0 to the app and defined a schema:
from sqlalchemy import create_engine, Column, Integer, Table
from sqlalchemy.ext.declarative import declarative_base
Base = declarative_base()
foo_table = Table('foo', Base.metadata,
Column('id', Integer, primary_key=True, autoincrement=True),
)
And when I tried to create the tables on the development server using:
url = 'mysql+gaerdbms:///%s?instance=%s' % ('database_name', 'instance_name')
engine = create_engine(url)
Base.metadata.create_all(engine)
...I got an error DBAPIError: (ImportError) No module named pwd None None, which means that SQLAlchemy is importing a module that is blacklisted by the development server.
Am I doing something wrong? Or, if not, what should I do to use SQLAlchemy on the development server? Or maybe the first question is: Can I use the SQLAlchemy's gaerdbms dialect to develop in a local MySql database using the dev server?
Edit: this error doesn't happen only when trying to create tables. I created the tables manually and tried to query them, and the same error occurs.
The full traceback is:
Traceback (most recent call last):
File "[...]/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1535, in __call__
rv = self.handle_exception(request, response, e)
File "[...]/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1529, in __call__
rv = self.router.dispatch(request, response)
File "[...]/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1278, in default_dispatcher
return route.handler_adapter(request, response)
File "[...]/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 1102, in __call__
return handler.dispatch()
File "[...]/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 572, in dispatch
return self.handle_exception(e, self.app.debug)
File "[...]/google_appengine/lib/webapp2-2.5.2/webapp2.py", line 570, in dispatch
return method(*args, **kwargs)
File "[...]/webapp/admin.py", line 12, in get
db.Base.metadata.create_all(engine)
File "[...]/webapp/sqlalchemy/schema.py", line 2784, in create_all
tables=tables)
File "[...]/webapp/sqlalchemy/engine/base.py", line 1486, in _run_visitor
with self._optional_conn_ctx_manager(connection) as conn:
File "/usr/lib/python2.7/contextlib.py", line 17, in __enter__
return self.gen.next()
File "[...]/webapp/sqlalchemy/engine/base.py", line 1479, in _optional_conn_ctx_manager
with self.contextual_connect() as conn:
File "[...]/webapp/sqlalchemy/engine/base.py", line 1669, in contextual_connect
self.pool.connect(),
File "[...]/webapp/sqlalchemy/pool.py", line 272, in connect
return _ConnectionFairy(self).checkout()
File "[...]/webapp/sqlalchemy/pool.py", line 425, in __init__
rec = self._connection_record = pool._do_get()
File "[...]/webapp/sqlalchemy/pool.py", line 855, in _do_get
return self._create_connection()
File "[...]/webapp/sqlalchemy/pool.py", line 225, in _create_connection
return _ConnectionRecord(self)
File "[...]/webapp/sqlalchemy/pool.py", line 318, in __init__
self.connection = self.__connect()
File "[...]/webapp/sqlalchemy/pool.py", line 368, in __connect
connection = self.__pool._creator()
File "[...]/webapp/sqlalchemy/engine/strategies.py", line 80, in connect
return dialect.connect(*cargs, **cparams)
File "[...]/webapp/sqlalchemy/engine/default.py", line 279, in connect
return self.dbapi.connect(*cargs, **cparams)
File "[...]/google_appengine/google/storage/speckle/python/api/rdbms_googleapi.py", line 183, in __init__
super(GoogleApiConnection, self).__init__(*args, **kwargs)
File "[...]/google_appengine/google/storage/speckle/python/api/rdbms.py", line 810, in __init__
self.OpenConnection()
File "[...]/google_appengine/google/storage/speckle/python/api/rdbms.py", line 832, in OpenConnection
self.SetupClient()
File "[...]/google_appengine/google/storage/speckle/python/api/rdbms_googleapi.py", line 193, in SetupClient
self._client = RdbmsGoogleApiClient(**kwargs)
File "[...]/google_appengine/google/storage/speckle/python/api/rdbms_googleapi.py", line 106, in __init__
rdbms.OAUTH_CREDENTIALS_PATH)
File "/usr/lib/python2.7/posixpath.py", line 259, in expanduser
import pwd
File "[...]/google_appengine/google/appengine/tools/devappserver2/python/sandbox.py", line 822, in load_module
raise ImportError('No module named %s' % fullname)
DBAPIError: (ImportError) No module named pwd None None

I found a workaround. As it is, SQLAlchemy's gaerdbms dialect can't connect to a local database. But with the dialect below it can. Folow the instructions from this answer but use this dialect instead:
# mysql/gaerdbms.py
# Copyright (C) 2005-2013 the SQLAlchemy authors and contributors <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""
.. dialect:: mysql+gaerdbms
:name: Google Cloud SQL
:dbapi: rdbms
:connectstring: mysql+gaerdbms:///<dbname>?instance=<instancename>
:url: https://developers.google.com/appengine/docs/python/cloud-sql/developers-guide
This dialect is based primarily on the :mod:`.mysql.mysqldb` dialect with minimal
changes.
.. versionadded:: 0.7.8
Pooling
-------
Google App Engine connections appear to be randomly recycled,
so the dialect does not pool connections. The :class:`.NullPool`
implementation is installed within the :class:`.Engine` by
default.
"""
import os
import re
from sqlalchemy.dialects.mysql.mysqldb import MySQLDialect_mysqldb
from sqlalchemy.pool import NullPool
class MySQLDialect_gaerdbms(MySQLDialect_mysqldb):
#classmethod
def dbapi(cls):
# from django:
# http://code.google.com/p/googleappengine/source/
# browse/trunk/python/google/storage/speckle/
# python/django/backend/base.py#118
# see also [ticket:2649]
# see also https://stackoverflow.com/q/14224679/34549
if is_production():
# Production mode.
from google.storage.speckle.python.api import rdbms_apiproxy
return rdbms_apiproxy
elif is_remote_mode():
# Development mode with remote database.
from google.storage.speckle.python.api import rdbms_googleapi
return rdbms_googleapi
else:
# Development mode with local database.
from google.appengine.api import rdbms_mysqldb
return rdbms_mysqldb
#classmethod
def get_pool_class(cls, url):
# Cloud SQL connections die at any moment
return NullPool
def create_connect_args(self, url):
opts = url.translate_connect_args()
if is_production() or is_remote_mode():
# 'dsn' and 'instance' are because we are skipping
# the traditional google.api.rdbms wrapper.
# they are not needed in local mode; 'dns' even causes an error.
opts['dsn'] = ''
opts['instance'] = url.query['instance']
return [], opts
def _extract_error_code(self, exception):
match = re.compile(r"^(\d+):|^\((\d+),").match(str(exception))
# The rdbms api will wrap then re-raise some types of errors
# making this regex return no matches.
code = match.group(1) or match.group(2) if match else None
if code:
return int(code)
dialect = MySQLDialect_gaerdbms
def is_production():
return os.getenv('SERVER_SOFTWARE', '').startswith('Google App Engine')
def is_remote_mode():
return os.getenv('SETTINGS_MODE') == 'prod'
This dialect uses a local database by default when running on the development server. To use remote access to Google Cloud SQL during development, a variable must be set in the environment, following the pattern used by Django:
os.environ['SETTINGS_MODE'] = 'prod'