Right now I have an app that write data for users to a database file called users.sql. However, I pushed this to heroku through github and the data doesn't stick. If a certain time has passed, heroku will sleep and all the files will have to be redeployed when another login is detected. I heard that I could add heroku postgres as an addon to heroku but I am not sure what to do to integrate this with my current code. What do I do to set it up?
I stumbled across your question while trying to connect my app to Postgres and getting very frustrated at the lack of clear instructions. So here's the step by step process with all the errors I struggled through (because that's where the tutorials leave you gasping for air while they thunder on obliviously...)
TL;DR
Install Postgres
Install the Heroku CLI
Install psycopg2 or psycopg2-binary and gunicorn
Create an app in Heroku with a Postgres database and save the database url as the SQLALCHEMY_DATABASE_URI
Create Procfile, requirements.txt and runtime.txt
Push to Github and connect repo to Heroku
Deploy branch
from app import db db.create_all()
I work with WSL so all command line syntax in my answer is Bash, and I'm working on Windows 10.
I'm working partly off a youtube tutorial by Traversy Media. Here's the Github repo he works with (I definitely recommend initially working with a basic app instead of struggling with the errors that crop up in a complex app with extra packages).
Before you start
Create an account in Heroku and install the Heroku CLI
Download and install PostgreSQL (this will also give you pgAdmin 4)
Fork and clone the Github repo, and check it runs ok (if you're not working with your own app)
Preliminaries
Create a virtual env and install all packages. Ensure you have psycopg2and gunicorn
ERROR: Failed building wheel for psycopg2-binary
For whatever reason, psycopg refuses to install on my system. You can get round this by using pip3 install psycopg2-binary instead - there's no difference as far as our requirements go.
Connect to Postgres
Open pgAdmin 4 from the start menu. This may prompt you for a password if it's the first time you're logging in or if you were logged out.
could not connect to server: Connection refused (0x0000274D/10061) Is the
server running on host "127.0.0.1" and accepting TCP/IP connections on port 5432?
Use sudo service postgresql status to check if the PostgreSQL server
is running. If it is, try stopping and starting it. If it isn't, start
it.
sudo service postgresql start
sudo service postgresql stop
In the left-hand panel, right-click on Databases and click Create > Database.... Enter your database name (the tutorial uses "lexus") and save.
In app.py (or wherever you do your database config) find the line
if ENV == 'dev':
...
app.config['SQLALCHEMY_DATABASE_URI'] = ''
and put the database connection string inside the quotes. The syntax is
postgresql://[username]:[password]#[host name]/[db name]
# [username] - Right-click on your server in pgAdmin (probably a variation of `PostgreSQL 13`). Go to the Connection tab and check the Username field.
# [password] - The root password you set the first time you logged in to pgAdmin.
# [host name] - In the same place as your username, in the Host name/address field.
# [db name] - The name you entered when creating your database.
In my case, the connection string is:
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://postgres:123456#localhost/lexus'
Important Disclaimer
This solution has you put the database password in code: app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://postgres:123456#localhost/lexus'
This saves the password in your version control history, where it can/will eventually allow anyone on the Internet to control your database. Yikes! Get DB user & password from env vars instead.
Thanks #Paul Cantrell!
Enter the python console and create the database:
>>> from app import db
>>> db.create_all()
If you didn't get an error on that, consider yourself the luckiest thing since sliced bread. In pgAdmin go to Databases > [your db name] > Schemas > Tables to check they've been created.
ImportError: cannot import name 'db' from 'app' (unknown location)
db is not located in app in your application. Find where it's
defined and import it from there.
(psycopg2.OperationalError) FATAL: password authentication failed for user "postgres"
You're using the wrong password. I found this confusing
because it's unclear whether you need to use the master password (the
one you set when logging in to pgAdmin for the first time) or the
password for the database you're connecting to. It's the master password that's needed here.
Enter psql -h 127.0.0.1 postgres (psql -h [ip address] [username]) in the command line - the password that authenticates is the one you need for the connection string.
(psycopg2.OperationalError) FATAL: database "lexus" does not exist
You might be connecting to the wrong database, using the wrong
username, or your database hasn't been created. Check your connection string and pgAdmin to confirm that details are correct.
db.create_all() seemed to work, but I have no tables in pgAdmin!
If your database models are stored in a separate file, import them
into app.py after db is initialised. It should look like this:
app = Flask(__name__)
...
db = SQLAlchemy(app)
...
from app.models import *
Send data to Postgres
Run the app and submit some data through the form (or create some data in your table). In pgAdmin, right-click the table you just created and refresh, then right-click and view/edit data.
Could not send data to server: Socket is not connected (0x00002749/10057) could not send SSL negotiation packet: Socket is not connected (0x00002749/10057)
Disconnect and reconnect server (right-click on server and click Disconnect Server, then Connect Server) and refresh table again.
If that didn't work, right-click on server and click Properties, go to the Connection tab and change the Host name/address from
localhost to 127.0.0.1. Then repeat step 1.
Create Heroku app
Since I prefer using Heroku directly with Github instead of the CLI, I'm not using git init here, but note that if your code is not already a Github repo you would need to use it.
In the command line:
heroku login # If you have the Heroku CLI installed correctly, this will open a tab in the browser and log you in to Heroku.
heroku create unique-app-name # (replace `unique-app-name` with your own name). This creates an app on the Heroku server, and it's the place your code is cloned to so that it can be run. Check that it has appeared in your [Heroku dashboard](https://dashboard.heroku.com/).
heroku addons:create heroku-postgresql:hobby-dev -a unique-app-name # This creates an empty postgres database for your app. Heroku uses its own database, not your pgAdmin database.
heroku config -a unique-app-name # The url you set earlier as the `SQLALCHEMY_DATABASE_URI` points to the database you created in pgAdmin, but since your app is now going to be using Heroku's database you need a new url. Copy the DATABASE_URL that is returned.
Go back to the code where you set app.config['SQLALCHEMY_DATABASE_URI'] earlier, and insert the new url inside the else block. It should look more or less like this:
if ENV == 'dev':
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://postgres:123456#localhost/lexus'
else:
app.config['SQLALCHEMY_DATABASE_URI'] = 'postgres://urlyoujustgotfromherokuozftkndvkayeyc:691196bfb1b1ca8318b733935b10c97a19fd41#ec2-52-71-161-140.compute-1.amazonaws.com:5432/d3pofh2b55a2ct'
If you're working with the tutorial's github repo, set ENV = 'prod', otherwise set the config to use the heroku url however you want.
Add the following files to your root directory if they're not yet included in your project files:
# Procfile
web: gunicorn app:app # The first `app` refers to the app.py and the second `app` refers to the app object, ie `app = Flask(__name__)`. Heroku needs this to know how to run your code.
# runtime.txt
python-3.8.5 # Find your python version by entering `python --version` or `python3 --version` in the command line.
# requirements.txt
# Create this by running `pip3 freeze > requirements.txt`. According to the [Heroku docs](https://devcenter.heroku.com/articles/python-runtimes)
# this must be done after changing runtime versions, so it's best to do it last.
Push everything to Github (again, this is if you're already in a repo otherwise you'd be using the Heroku CLI process which I'm not following).
Deploy on Heroku
Click on the app you created previously in the Heroku dashboard and go to the Deploy tab. In the Deployment method options, click Github. Connect your Github account and repository.
Scroll down to the Manual deploy section and select the branch you want to deploy (or just leave it as master if that's the only one). Click Deploy Branch.
Requested runtime (python-3.7.2) is not available for this stack (heroku-20).
! Aborting. More info: https://devcenter.heroku.com/articles/python-support
! Push rejected, failed to compile Python app.
! Push failed
It looks like the python version is wrong. Check that runtime.txt is showing the right python version. If it
isn't, update it, delete and recreate requirements.txt, push to
Github and click Deploy Branch again.
Create Heroku database
Back in the command line:
heroku run python3
>>> from app import db
>>> db.create_all()
To check out your database, enter
heroku pg:psql --app unique-app-name
If you run select * from tablename; nothing will be returned because there isn't any data yet.
Click the View button in Heroku to open your app. Submit the form (or enter data however your app works), then run select * from tablename; again and you'll see the row of data.
In your init.py file you can set up your app.config['SQLALCHEMY_DATABASE_URI'] variable such that it will look for the one Heroku will give your application if it's running on heroku, OR use the configuration for your local database if it's running locally. You can achieve this as such:
app.config['SQLALCHEMY_DATABASE_URI'] = environ.get('DATABASE_URL') or "postgresql://postgres:password#localhost:5432/postgres"
replace what is after the OR w/ the connection details for your local connection
I would suggest considering setting up a local postgres database instead of sql if you're going to use heroku but you can technically use both. You just may run into minor issues, I have ran into issues w/ dates being handled slightly different, for example.
Firstly make heroku login from terminal:
$ heroku login
Now create the database for your app using following command:
$ heroku addons:create heroku-postgresql:hobby-dev --app app_name
Now after your Database has been created, get the URL of your Database using the following command:
$ heroku config --app app_name
Now that you have got your Database URL, replace the value of app.config[‘SQLALCHEMY_DATABASE_URI’] line in the “app.py” file with this Database URL:
app.config['SQLALCHEMY_DATABASE_URI'] = 'heroku_database_url'
And finally push code to heroku.
Related
while running the rest api which is deployed in heroku. I am getting below error which says not able to access mongodb
Currently i am accessing mongodb using pymongo.MongoClient("mongodb://localhost:27017/") ,may i know how to configure this ,so that i can access the db .
Thanks
Sumesh
Since you said that you haven't hosted the DB somewhere, I'll explain how to set things up with mLab and get the DB up and running.
Create an account in mLab and create a database in it.
Then create a user inside that database. We can use this to deploy your local database to mLab
Create a dump of your DB
mongodump -d <DB_NAME>
Then restore the db to your mLab instance
mongorestore -h <DB_URL> -u <DB_USERNAME> -p <DB_PASSWORD> --authenticationDatabase <MLAB_DB_NAME> -d <LOCAL_DB_NAME> <DB_DUMP_LOCATION>
After successfully deploying the db, you can set the connection string in Heroku
heroku config:set MONGOLAB_URI=mongodb://username:password#<DB_URL>/<DB_NAME>
Then, set the connection string in python application
import os
pymongo.MongoClient(os.environ['MONGOLAB_URI'])
For more info:
https://medium.com/miguel-garcia/heroku-and-mlab-with-mongodb-free-the-easy-way-ec2ae80073f7
https://forum.freecodecamp.org/t/how-to-deploy-your-mongodb-app-to-heroku/19347
How can I run the full Flask Tutorial app in the Wingware IDE?
I've been using Flask under Wing Pro 7.2 for some time, and can get control because I start Flask by doing app.run() in Wing.
I conceived a wish to trace through the official working version of the completed tutorial, obtained by
git clone https://github.com/pallets/flask
This works fine (using 'flask run'), and I now have the complete source. But there's no app.run() anywhere. I tried putting one in init.py:
def create_app(test_config=None):
#...
db.init_app(app)
return app
RUN = True
if RUN:
app= create_app()
app.run()
and flask starts up, but throws an error on request 'localhost:5000/', which normally fires up a database form.
Is there a starting point in the Python code somewhere?
Or, is it possible to attach Wing to a running flask, and tell it about the source files? There is a bit in the Wing manual about attaching, but it seems to demand information about the target that we lack.
I managed to start the tutorial by creating a file main.py in the same directory as the flaskr package, with this contents:
import flaskr
app = flaskr.create_app()
app.debug = False
app.run(use_reloader=True)
Then I set this as the main debug file in Wing.
To make debugging work correctly, you may also need to set the Python Executable in Project Properties (from the Project menu) to the Python command line or activated env you want to use.
Also, it is important to set Debug/Execute > Debug Child Processes in Project Properties to Always Debug Child Processes. Otherwise the process actually running the app code is not debugged.
This works but results in a SQL error because the table 'post' does not exist if you did not already run the following first to initialize the database:
$ export FLASK_APP=flaskr
$ export FLASK_ENV=development
$ flask init-db
Once I did that, everything worked for me.
I have a Django app (with a postgresql backend) which I used to test on a local development server, and then simply push to Heroku (my service of choice). I had a Procfile that told Heroku dynos what processes to spin up, and then never worried about anything else.
I'm now migrating to Azure, where I'm setting up my own VM (v1) to host my app + postgres db. Now I need to set up my own webserver as well, which I unfortunately have thin experience of. So can someone guide me how to set up my own webserver? My ultimate goal is to set up Gunicorn with NginX as a reverse proxy. The first step, though, is to set up just Gunicorn for starters, and start seeing some HTTP traffic. How do I do that?
Here's my directory structure:
app/
__init__.py
models.py
tests.py
views.py
project/
__init__.py
wsgi.py
urls.py
settings.py
celery.py
static/
templates/
middleware/
The contents of my wsgi.py file are:
import os
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "project.settings")
from django.core.wsgi import get_wsgi_application
from dj_static import Cling
application = Cling(get_wsgi_application())
I tried the following:
gunicorn -b 0.0.0.0:8080 project.wsgi:application
It fires up; I see the following:
I likewise added endpoints in my Azure VM like so:
I likewise added endpoints for port 5432. Finally, when I run this I get the error:
Is the server running on host "localhost" (127.0.0.1) and accepting TCP/IP connections on port 5432?. Can you point out what I'm doing wrong?
According your description, it seems a PostgreSQL configuration issue. As I have a quick test on ubuntu + PostgreSQL + python27 + psycopg2 to test the connection to local PostgreSQL on Azure VM. However, I cannot reproduce your issue, it works fine on my side. Here are my steps of installing PostgreSQL service and test on python, for your information:
1, remote to Azure VM, and install PostgreSQL via sudo apt-get update, sudo apt-get install PostgreSQL postgresql-contrib
2, create a new PostgreSQL user: psql , ` create user someuser password 'somepassword';
3, install PostgreSQL service which is required by psycopg2 : sudo apt-get install postgresql-server-dev-9.4
4, install python package psycopg2: sudo apt-get install python-pip and sudo apt-get install python-psycopg2
5, And test in python code:
import psycopg2
try:
conn = psycopg2.connect("dbname='postgres' user=' someuser' host='localhost' password='somepassword'")
cur = conn.cursor()
cur.execute("""SELECT 1=1""")
rows = cur.fetchall()
for row in rows:
print " ", row[0]
except:
print "I am unable to connect to the database"
And specific to your issue, I think you can quick check the following points for troubleshooting:
1, make sure your PostgreSQL service is running, because of here is an issue with the same error message with you Posgresql connection through port 5432.
2, make sure the host setting of PostgreSQL in your Django app is “localhost”, and you can easy test in psql –h localhost -Usomeuser to login on PostgreSQL. If you occur the issue, you can try to configure your PostgreSQL server shown in Postgresql and TCP/IP connections on port 5432.
So i used postgres in development for my django project and have important entries in there and i want to deploy to my app in heroku
is there a simple way to do this?
Sure. You just need to export your local database and import it on the Heroku Postgres database. Heroku has a guide to do just that.
Create a dump from your local database. PGPASSWORD=mypassword pg_dump -Fc --no-acl --no-owner -h localhost -U myuser mydb > mydb.dump
Upload mydb.dump somewhere Heroku can access it.
Import to heroku. heroku pg:backups restore 'https://s3.amazonaws.com/me/items/3H0q/mydb.dump' DATABASE_URL
Source
I'm trying to setup Fabric so that I can automatically deploy my Django app to my web server.
What I want to do is to pull the data from my Development machine (os X) to the server.
How do I correctly specify my path in the git url?
This is the error I'm getting:
$ git pull
fatal: '/Users/Bryan/work/tempReview_app/.': unable to chdir or not a git archive
fatal: The remote end hung up unexpectedly
This is .git/config:
[core]
repositoryformatversion = 0
filemode = true
bare = false
logallrefupdates = true
ignorecase = true
[remote "origin"]
fetch = +refs/heads/*:refs/remotes/origin/*
url = /Users/Bryan/work/my_app/.
[branch "master"]
remote = origin
merge = refs/heads/master
On your server, create a folder called myapp. Chdir to this folder, and then run
server ~/myapp$ git init
Then, let git know about your server. After this, push to the server's repository from your local machine.
local ~/myapp$ git remote add origin user#server:~/myapp.git
local ~/myapp$ git push origin master
Anytime you want to push changes to your server, just run git push. If you make a mistake, just log in to your server and git co last-known-good-commit or something to that effect.
Git hooks are also very useful in situations such as the one you're facing. I would give you pointers on that but I don't know what your workflow is like, so it probably wouldn't be very helpful.