app.py

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_compress import Compress
from flask_debugtoolbar import DebugToolbarExtension

from sqlalchemy import exc
from sqlalchemy import event
from sqlalchemy import func
from sqlalchemy.pool import Pool
from sqlalchemy.pool import NullPool

from util import safe_commit
from util import elapsed
from util import HTTPMethodOverrideMiddleware
from util import read_csv_file

import logging
import sys
import os
import requests
import redis
import time
import json
from collections import defaultdict
from rq import Queue

# set up logging
# see http://wiki.pylonshq.com/display/pylonscookbook/Alternative+logging+configuration
logging.basicConfig(
    stream=sys.stdout,
    level=logging.DEBUG,
    format='%(name)s - %(message)s'
)
logger = logging.getLogger("software")

libraries_to_mum = [
    "requests.packages.urllib3",
    "requests_oauthlib",
    "stripe",
    "oauthlib",
    "boto",
    "newrelic",
    "RateLimiter",
    "urllib3",
    "paramiko",
    "chardet"
]

for a_library in libraries_to_mum:
    the_logger = logging.getLogger(a_library)
    the_logger.setLevel(logging.WARNING)
    the_logger.propagate = True

requests.packages.urllib3.disable_warnings()

app = Flask(__name__)
# app.debug = True

# database stuff
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = True  # as instructed, to supress warning
app.config["SQLALCHEMY_DATABASE_URI"] = os.getenv("DATABASE_URL")
app.config['SQLALCHEMY_ECHO'] = (os.getenv("SQLALCHEMY_ECHO", False) == "True")

# from http://stackoverflow.com/a/12417346/596939
class NullPoolSQLAlchemy(SQLAlchemy):
    def apply_driver_hacks(self, app, info, options):
        options['poolclass'] = NullPool
        return super(NullPoolSQLAlchemy, self).apply_driver_hacks(app, info, options)

db = NullPoolSQLAlchemy(app)


# do compression.  has to be above flask debug toolbar so it can override this.
compress_json = os.getenv("COMPRESS_DEBUG", "False")=="True"


# set up Flask-DebugToolbar
if (os.getenv("FLASK_DEBUG", False) == "True"):
    logger.info("Setting app.debug=True; Flask-DebugToolbar will display")
    compress_json = False
    app.debug = True
    app.config['DEBUG'] = True
    app.config["DEBUG_TB_INTERCEPT_REDIRECTS"] = False
    app.config["SQLALCHEMY_RECORD_QUERIES"] = True
    app.config["SECRET_KEY"] = os.getenv("SECRET_KEY")
    toolbar = DebugToolbarExtension(app)

# gzip responses
Compress(app)
app.config["COMPRESS_DEBUG"] = compress_json


# for running rq jobs
ti_queues = []

redis_rq_conn = redis.from_url(
    os.getenv("REDIS_URL", "redis://127.0.0.1:6379"),
    db=0
)

for i in range(0, 2):  # number of queues to spin up
    ti_queues.append(
        Queue("ti-queue-{}".format(i), connection=redis_rq_conn)
    )


# imports got here for tables that need auto-created.
# from models import temp_orcid_profile
# from models import temp_product
#
# from models import person
# from models import product
# from models import badge
# from models import refset
# from models import email
# from models import log_temp_profile
# from models import log_openness
#
# db.create_all()
# commit_success = safe_commit(db)
# if not commit_success:
#     print u"COMMIT fail making objects"


# from http://docs.sqlalchemy.org/en/latest/core/pooling.html
# This recipe will ensure that a new Connection will succeed even if connections in the pool 
# have gone stale, provided that the database server is actually running. 
# The expense is that of an additional execution performed per checkout
@event.listens_for(Pool, "checkout")
def ping_connection(dbapi_connection, connection_record, connection_proxy):
    cursor = dbapi_connection.cursor()
    try:
        cursor.execute("SELECT 1")
    except:
        # optional - dispose the whole pool
        # instead of invalidating one at a time
        # connection_proxy._pool.dispose()

        # raise DisconnectionError - pool will try
        # connecting again up to three times before raising.
        raise exc.DisconnectionError()
    cursor.close()