Why are two objects being created in my sqlalchemy init? [duplicate] - flask

Question

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Why does running the Flask dev server run itself twice?
(7 answers)
Closed 5 years ago.
This is my Model:
class Category(db.Model):
__tablename__='category'
id = db.Column(db.Integer,primary_key=True)
items = db.relationship('Item',backref='category',lazy='dynamic')
name = db.Column(db.String(80))
order = db.Column(db.Integer)
private = db.Column(db.Boolean)
color = db.Column(db.String(80),unique=False)
def __init__(self,name,order=None,private=None):
r = lambda: random.randint(0, 255)
color = (r(), r(), r())
color = ('#%02X%02X%02X' % color)
count = db.session.query(Category).count()
print count
self.name = name
self.color = color
self.order = count+1
self.private = 1
def __repr__(self):
return '<Category %r>' % self.name
and I create the tables here:
def initialize_tables():
db.create_all()
c = Category(name="uncategorized")
db.session.add(c)
db.session.commit()
if __name__ == '__main__':
initialize_tables()
app.run(debug=True)
This creates two categories in my database named 'uncategorized'. Why is this happening?

Answer 1

That's because you're using app.run with debug=True:
If the debug flag is set the server will automatically reload for code changes and show a debugger in case an exception happened.
The way the reloader works is by starting itself again in a subprocess, so if __name__ == '__main__' (and hence initialize_tables) runs twice.