有没有更好的方法来获取flask的app_context？

Question

In Flask, I start another thread to run a time consuming task which need to update mysql, how could I use Flask_sqlalchemy in this thread?

I try to run a bash script when request a url in my website. Because the bash script need long time to run, I don't want it block the flask's main thread . So I start another thread to run it. When I did this, I find that I need to get flask's app_context to use Flask_sqlalchemy . So I did like this:

part of my code:

@manage_git.route('/makefile', methods=['POST'])
def makefile():
    Threading(target=mkfile, args=(local_git_dir, git_id)).start()
    return redirect(url_for('manage_git.index'))

def mkfile(local_git_dir, git_id):
    from manage import app
    subprocess.Popen(['bash', 'makefile.sh'])
    with app.app_context():
        git_db = GitDb.query.filter_by(id=git_id).first()
        git_db.make = True
        db.session.add(git_db)
        db.session.commit()

I just want app_context to use Flask_sqlalchemy, but I import a Global Variable app . I don't think it is a good way to solve this problem.

It would help me a lot, If you could tell me about: Is there any better way to get flask's app_context? Or is there another better way to solve my problem?

----supplementary----

exts.py :

from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

init .py :

from flask import FLask

from config import config

from .exts import db, login_manager


def create_app(config_name):
    app = Flask(__name__)
    app_config = config[config_name]
    app.config.from_object(app_config)
    app_config.init_app(app)

    db.init_app(app)

    from .manage_git import manage_git as manage_git_blueprint
    app.register_blueprint(manage_git_blueprint)
    # ......
    return app

manage.py :

from app import create_app

from app.models import *

app = create_app('default')

if __name__ == '__main__':
    app.run()

Answer 1

How are you creating your app and db objects? According to the Flask-SQLAlchemy docs, if you are only using on App object, you can just pass the app object to your SQLAlchemy() call:

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/test.db'
db = SQLAlchemy(app)

Now when you import the db, you would not have a need to import the app or using the app_context:

def mkfile(local_git_dir, git_id):
    subprocess.Popen(['bash', 'makefile.sh'])
    git_db = GitDb.query.filter_by(id=git_id).first()
    git_db.make = True
    db.session.add(git_db)
    db.session.commit()

http://flask-sqlalchemy.pocoo.org/2.3/contexts/ and http://flask-sqlalchemy.pocoo.org/2.3/quickstart/ have more information about this process and the alternatives.