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schema in one place, abstract sqlalchemy vs django

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stnbu committed Sep 1, 2018
1 parent 94026e1 commit 24cd4b40520efb40bda5a0181f4b83b42fe08304
Showing with 134 additions and 33 deletions.
  1. +5 −33 coincharts/daemon/base.py
  2. +129 −0 coincharts/schema.py
@@ -19,7 +19,7 @@
import daemon
import daemon.pidfile
from mutils import simple_alchemy
from coincharts import schema
logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)
@@ -45,22 +45,6 @@ class PriceSeries(object):
date_format_template = '%Y-%m-%dT%H:%M:%S.%f0Z' # magic
headers = {'X-CoinAPI-Key':
open(API_KEY_FILE).read().strip()}
schema = [
('time_period_start', 'TEXT'),
('time_period_end', 'TEXT'),
('time_open', 'TEXT'),
('time_close', 'TEXT'),
('price_open', 'REAL'),
('price_high', 'REAL'),
('price_low', 'REAL'),
('price_close', 'REAL'),
('volume_traded', 'REAL'),
('trades_count', 'INTEGER'),
]
# these are THE values we care about, so CAPS
TIME = 'time_period_end'
PRICE = 'price_close'
# this is the beginning of time if we don't have any local data
first_date = '2018-01-09T00:00:00.0000000Z'
@@ -73,7 +57,7 @@ def get_db_session(cls, dir_path):
if cls._session is not None:
return cls._session
db_path = os.path.join(os.path.abspath(dir_path), 'db.sqlite3')
cls._session = simple_alchemy.get_session(db_path)
cls._session = schema.get_sqlalchemy_session(db_path)
return cls._session
@classmethod
@@ -101,19 +85,7 @@ def __init__(self, symbol_id, dir_path):
logger.debug('creating PriceSeries object for {}'.format(symbol_id))
self.symbol_id = symbol_id
self.dir_path = dir_path
schema = [
('time_period_start', String),
('time_period_end', String),
('time_open', String),
('time_close', String),
('price_open', Float),
('price_high', Float),
('price_low', Float),
('price_close', Float),
('volume_traded', Float),
('trades_count', Integer),
]
self.data = simple_alchemy.get_table_class(symbol_id, schema=schema)
self.data = schema.get_db_table(symbol_id, 'sqlalchemy')
def get_prices_since(self, start_dt):
"""Get prices for this PriceSeries where datetime is greater or equal to `start_dt`
@@ -125,7 +97,7 @@ def get_prices_since(self, start_dt):
except TypeError:
pass
start_dt = self.get_normalized_datetime(self.round_up_hour(start_dt))
kwargs = {self.TIME: start_dt}
kwargs = {schema.datetime_field: start_dt}
session = self.get_db_session(self.dir_path)
first = session.query(self.data).filter_by(**kwargs).first()
results = session.query(self.data).filter(id >= first).first()
@@ -180,7 +152,7 @@ def get_last_date_from_store(self):
obj = session.query(self.data).order_by(self.data.id.desc()).first()
if obj is None:
return parse_dt(self.first_date)
dt = getattr(obj, self.TIME)
dt = getattr(obj, schema.datetime_field)
return parse_dt(dt)
def insert(self, data):
@@ -0,0 +1,129 @@
# -*- mode: python; coding: utf-8 -*-
"""Abstraction for sqlalchemy vs django engines.
"""
# It may be better/easier to just use django in place of sqlalchemy. TBD.
import os
from types import MethodType
import atexit
import django.db.models
import sqlalchemy.types
import sqlalchemy.ext.declarative
datetime_field = 'time_period_end'
price_field = 'price_close'
schema = [
('time_period_start', 'TEXT'),
('time_period_end', 'TEXT'),
('time_open', 'TEXT'),
('time_close', 'TEXT'),
('price_open', 'REAL'),
('price_high', 'REAL'),
('price_low', 'REAL'),
('price_close', 'REAL'),
('volume_traded', 'REAL'),
('trades_count', 'INTEGER'),
]
type_mappings = {
'django': {
'TEXT': django.db.models.CharField,
'REAL': django.db.models.FloatField,
'INTEGER': django.db.models.IntegerField,
},
'sqlalchemy': {
'TEXT': sqlalchemy.types.String,
'INTEGER': sqlalchemy.types.Integer,
'REAL': sqlalchemy.types.Float,
},
}
# to-be-bound to classes created below
def __str__(self):
class_name = self.__class__.__name__
return '<{}({}@{})>'.format(
class_name,
getattr(self, TIME),
getattr(self, PRICE),
)
Base = None
def get_db_table(symbol_id, orm):
global Base
mapping = type_mappings[orm]
columns = {}
for name, type_ in schema:
type_ = mapping[type_]
if orm == 'django':
columns[name] = type_()
elif orm == 'sqlalchemy':
columns[name] = sqlalchemy.Column(type_)
else:
raise Exception('Unknown ORM "{}"'.format(orm))
if orm == 'django':
klass = type(symbol_id, (models.Model,), columns)
klass.__str__ = __str__
elif orm == 'sqlalchemy':
Base = sqlalchemy.ext.declarative.declarative_base()
columns['__tablename__'] = symbol_id.lower()
columns['id'] = sqlalchemy.Column(sqlalchemy.types.Integer, primary_key=True)
klass = type(symbol_id, (Base,), columns)
klass.__repr__ = __str__
else:
raise Exception('fixme: tooooo complicated')
return klass
def get_sqlalchemy_session(db_path, echo=False):
"""Create and return a SQLAlchemy `session` object
"""
db_path = os.path.abspath(db_path)
engine = sqlalchemy.create_engine('sqlite:///{db_path}'.format(db_path=db_path), echo=echo)
Session = sqlalchemy.orm.sessionmaker(bind=engine)
session = Session()
Base.metadata.create_all(engine)
atexit.register(session.close)
return session
"""
class Page(models.Model):
weight = models.FloatField(default=0.0)
name = models.CharField(max_length=30)
label = models.CharField(max_length=60)
headline = models.CharField(max_length=200)
tab_visible = models.BooleanField('Should tab be visible?', default=True)
def __str__(self):
return self.name
class Content(models.Model):
page = models.ForeignKey(Page, on_delete=models.CASCADE)
main = models.TextField(blank=True)
rhs = models.TextField(blank=True)
def __str__(self):
return self.page.name
"""
"""
from sqlalchemy import Column, Integer, String
class User(Base):
__tablename__ = 'users'
id = Column(Integer, primary_key=True)
name = Column(String)
fullname = Column(String)
password = Column(String)
def __repr__(self):
return "<User(name='%s', fullname='%s', password='%s')>" % (
self.name, self.fullname, self.password)
"""

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