String url calls sqlalchemy and sqlalchemy calls for psycopg2

[Nikolay_Klimov]

This code:

import pandas as pd
import plotly.express as px
import streamlit as st

@st.cache(allow_output_mutation=True)
def get_data():
df = pd.read_sql(‘diesel-price-by-regions’, ‘string-LINK-to-cloud-POSTGRES’)
return df

df = get_data()

#prepare thr chart
fig = px.line(df, x=‘date’, y=‘diesel_price’, color=‘region’,
title=‘Diesel price in the US’,
labels={‘date’:‘Date’,
‘diesel_price’:‘Price ($)’, ‘region’:‘Region’})

fig.update_layout(legend=dict(
yanchor=“top”,
y=0.99,
xanchor=“left”,
x=0.01
))

st.plotly_chart(fig)

Returns

File “/home/appuser/venv/lib/python3.10/site-packages/sqlalchemy/engine/create.py”, line 548, in create_engine
dbapi = dialect_cls.dbapi(**dbapi_args)
File “/home/appuser/venv/lib/python3.10/site-packages/sqlalchemy/dialects/postgresql/psycopg2.py”, line 811, in dbapi
import psycopg2
ModuleNotFoundError: No module named ‘psycopg2’

I saw many topics about the same issue but did understand the way to pull data from the cloud postgress without psycopg2.

How to deal with it?

[ennui]

Edit: disregard, I just realized you are talking about the cloud deployment.

[blackary]

Do you have psycopg2 in your requirements.txt?

Even though you’re not using psycopg2 explicitly, that’s what pandas uses under the hood for reading from a postgres db.

[Nikolay_Klimov]

no, it is not there. And it is my problem to understand how to overcome this.
I solved the problem by transferring the service to Dash.

[blackary]

If you add the line psycopg2 to a file called requirements.txt, it will automatically install that when you deploy to Streamlit Cloud.

[Nikolay_Klimov]

I tried and it seems like Streamlit Cloud rejects any calls related to activities related to hosting DBs.

[blackary]

It does not – we regularly use Streamlit Cloud to read from a wide variety of databases. Could you try following this tutorial here? Connect Streamlit to PostgreSQL - Streamlit Docs

[Nikolay_Klimov]

huh, somehow I missed this part of the tutorial. Thanks. I’l play with it when I need quick release to the web