I'm trying to deploy a flask app on AWS Lambda using Zappa. However, when I call zappa deploy dev, I'm getting an error. After examining the logs, I've found that the error is being caused when the code runs db.create_all() within my create_database() function. The database isn't being created which is strange because when I run it locally, it works fine. I'm including the code for my application and a stack trace of the error below.
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from os import path
from flask_login import LoginManager
db = SQLAlchemy()
DB_NAME = 'database.db'
def create_app():
app = Flask(__name__)
app.config['SECRET_KEY'] = 'asdfghjkl'
app.config['SQLALCHEMY_DATABASE_URI'] = f'sqlite:///{DB_NAME}'
db.init_app(app)
from .views import views
app.register_blueprint(views, url_prefix = '/')
from .models import User
create_database(app)
login_manager = LoginManager()
login_manager.login_view = 'views.home'
login_manager.init_app(app)
#login_manager.user_loader
def load_user(id):
return User.query.get(int(id))
return app
def create_database(app):
if not path.exists('website/' + DB_NAME):
db.create_all(app = app) #where error is occuring
print('Created Database')
After running zappa deploy/update dev:
Any help would be appreciated!
Everything was working fine, the imports have always worked and my project structure has not changed. I made some changes - adding fields & forms, and suddenly all the relative imports in my app/main/views.py stopped working. I reverted my changes - that did not work either. Help!
Update: So it runs fine from the command line with "flask run", but not in PyCharm. So I'm thinking it's PyCharm config issue. My config.py file has not changed at all, so I think it's here: PyCharm Run/Debug Config
I did not intentionally make ANY changes to the config.... so not sure what the next step is here. If anyone has advice on the config for this project, I would be grateful!
Here's the project structure. App, Auth and Main are shown as packages:
Project Structure
Here's the main app demo.py:
import os
from app import create_app, db
from app.models import Org, User, Role, DemoType, DemoReport, DemoRptQ, \
Demo, Question, Answer, Location
from flask_migrate import Migrate
app = create_app(os.getenv('FLASK_CONFIG') or 'default')
migrate = Migrate(app, db)
#app.shell_context_processor
def make_shell_context():
return dict(db=db, Org=Org, User=User, Role=Role, Location=Location,
DemoType=DemoType, DemoReport=DemoReport, DemoRptQ=DemoRptQ, Demo=Demo,
Question=Question, Answer=Answer)
#app.cli.command()
def test():
import unittest
tests = unittest.TestLoader().discover('tests')
unittest.TextTestRunner(verbosity=2).run(tests)
Here's the app init.py
from flask import Flask
from flask_bootstrap import Bootstrap
from flask_mail import Mail
from flask_moment import Moment
from flask_sqlalchemy import SQLAlchemy
from flask_login import LoginManager
from config import config
bootstrap = Bootstrap()
mail = Mail()
moment = Moment()
db = SQLAlchemy()
login_manager = LoginManager()
login_manager.login_view = 'auth.login'
def create_app(config_name):
app = Flask(__name__)
app.config.from_object(config[config_name])
config[config_name].init_app(app)
bootstrap.init_app(app)
mail.init_app(app)
moment.init_app(app)
db.init_app(app)
login_manager.init_app(app)
from .main import main as main_blueprint
app.register_blueprint(main_blueprint)
from .auth import auth as auth_blueprint
app.register_blueprint(auth_blueprint, url_prefix='/auth')
return app
And the app/main package init.py:
from flask import Blueprint
main = Blueprint('main', __name__)
from . import views, errors
from ..models import Permission
#main.app_context_processor
def inject_permissions():
return dict(Permission=Permission)
And finally the app/main views.py, where I am getting the error on the third line from .. import db
from datetime import datetime
from flask import render_template, session, redirect, url_for, flash
from .. import db
from ..models import User, Role, Location, Demo, Question, Answer, DemoType, DemoReport, DemoRptQ
from ..email import send_email
from . import main
from .forms import DashboardForm, EditProfileForm, EditProfileAdminForm, DemosForm, DemoForm
from .forms import QuestionsForm, QuestionForm, DemoTypesForm, DemoTypeForm, DemoReportsForm, DemoReportForm
from .forms import AnswerForm, AnswersForm, LocationsForm, LocationForm
from .forms import UsersForm
from flask_login import login_required, current_user
from ..decorators import admin_required
from wtforms.validators import DataRequired, Optional, Length
#main.route('/', methods=['GET', 'POST'])
def index():
form = DashboardForm()
if form.validate_on_submit():
btn = form.submit.raw_data[0]
if btn == 'Demos':
return redirect(url_for('.demos_list'))
elif btn == 'New Demo':
return redirect(url_for('.edit_demo', id=0))
elif btn == 'Login':
return redirect(url_for('auth.login'))
elif btn == 'Register':
return redirect(url_for('auth.register'))
return render_template('index.html', form=form, isauth=current_user.is_authenticated)
#main.route('/users')
def users_list():
form = UsersForm()
if form.validate_on_submit():
return redirect(url_for('.index'))
I found this answer in another post and it worked! In Pycharm Run/Debug Configs, uncheck "Add Content Roots to PYTHONPATH" and "Add Source Roots to PYTHONPATH". Don't understand why it broke or why it's fixed... but there's plenty of time for that later.
PyCharm Config Fix
I see below error even after setting secret_key, unable to figure out what i'm missing here please advice
Error:
RuntimeError: The session is unavailable because no secret key was set. Set the secret_key on the application to something unique and secret.
Code below
config.py
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_login import LoginManager
#from .models import db
db = SQLAlchemy()
def create_app():
app = Flask(__name__)
app.config['secret_key'] = '\x90vv\xdd\x11?<\xbf \xd3\xb2\xab\x12\xb5\xa3\xee'
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://postgres:admin#localhost:5432/WebApp'
db.init_app(app)
login_manager = LoginManager()
login_manager.login_view = 'auth.login'
login_manager.init_app(app)
from .models import Person
#login_manager.user_loader
def load_user(user_id):
return Person.query.get(int(user_id))
from .auth import auth as auth_blueprint
app.register_blueprint(auth_blueprint)
return app
There are a few ways of setting a secret key for Flask application.
Using app.config, the SECRET_KEY part must be uppercase here which is why you're receving an error:
app.config['SECRET_KEY'] = 'my-secret-key'
Using Flask application object:
app.secret_key = 'my-secret-key'
More information can be found in Flask documentation: https://flask.palletsprojects.com/en/1.1.x/api/#flask.Flask.secret_key
I have the following project structure:
project/__init__.py
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
db = SQLAlchemy()
migrate = Migrate()
def create_app():
app = Flask(__name__)
app.config.from_object(os.environ['APP_SETTINGS'])
db.init_app(app)
migrate.init_app(app, db)
return app
run.py
from project import create_app
app = create_app()
if __name__ == "__main__":
app.run()
manage.py
from flask_script import Manager
from flask_migrate import MigrateCommand
from project.models import *
from project import create_app
manager = Manager(create_app)
manager.add_command('db', MigrateCommand)
if __name__ == '__main__':
manager.run()
Yet when I run the following commands, Flask-Migrate is not detecting any tables to be added.
python manage.py db init
Which outputs:
Creating directory $HOME/Project/migrations ... done
Creating directory $HOME/Project/migrations/versions ... done
Generating $HOME/Project/migrations/script.py.mako ... done
Generating $HOME/Project/migrations/env.py ... done
Generating $HOME/Project/migrations/README ... done
Generating $HOME/Project/migrations/alembic.ini ... done
Please edit configuration/connection/logging settings in
'$HOME/Project/migrations/alembic.ini' before proceeding.
and
python manage.py db migrate
Which only outputs:
INFO [alembic.runtime.migration] Context impl PostgresqlImpl.
INFO [alembic.runtime.migration] Will assume transactional DDL.
Why is Flask-Migrate with Alembic not detecting the Models and therefore creating the tables? Here's what I've tried:
Deleting the database, starting from nothing
Creating a custom db class inside the manage.py file, doesn't detect that
Googling every answer to this problem, found lots of similar questions but none of their solutions worked for me.
EDIT:
Here is an example of the models.py file
from flask import current_app
from project import db
from flask_login import UserMixin
class User(db.Model, UserMixin):
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(50))
The solution was to import the models in the __init__.py file like so:
def create_app():
app = Flask(__name__)
app.config.from_object(os.environ['APP_SETTINGS'])
from project import models
db.init_app(app)
migrate.init_app(app, db)
return app
I had the same issue. The solution is pretty same as #joe's
In routes file
from models import User
api_user = Namespace('user', description='user related operations')
In project/__init__.py
def create_app():
app = Flask(__name__)
app.config.from_object(os.environ['APP_SETTINGS'])
from project import models
db.init_app(app)
migrate.init_app(app, db)
blueprint = Blueprint('api', __name__, url_prefix=url_prefix)
api = Api(blueprint, doc='/documentation') # ,doc=False
app.register_blueprint(blueprint)
api.add_namespace(api_user)
return app
when adding api_user namespace in create_app flask_migrate detected models
I have the following structure in my project
\ myapp
\ app
__init__.py
views.py
run.py
And the following code:
run.py
from app import create_app
if __name__ == '__main__':
app = create_app()
app.run(debug=True, host='0.0.0.0', port=5001)
views.py
#app.route("/")
def index():
return "Hello World!"
_init_.py
from flask import Flask
def create_app():
app = Flask(__name__)
from app import views
return app
I'm trying to use the factory design pattern to create my app objects with different config files each time, and with a subdomain dispatcher be able to create and route different objects depending on the subdomain on the user request.
I'm following the Flask documentation where they talk about, all of this:
Application Context
Applitation Factories
Application with Blueprints
Application Dispatching
But I couldn't make it work, it seems that with my actual project structure there are no way to pass throw the app object to my views.py and it throw and NameError
NameError: name 'app' is not defined
After do what Miguel suggest (use the Blueprint) everything works, that's the final code, working:
_init.py_
...
def create_app(cfg=None):
app = Flask(__name__)
from api.views import api
app.register_blueprint(api)
return app
views.py
from flask import current_app, Blueprint, jsonify
api = Blueprint('api', __name__)
#api.route("/")
def index():
# We can use "current_app" to have access to our "app" object
return "Hello World!"