Sniff: web application scaffold

This is a web application demonstration repo. It's a barebones newsfeed-style app used to scaffold the folliwing tech stack:

Frontend stack:

• React SPA
• Nginx for serving SPA and proxying to backend requests
• Forms using Formik with validation via Yup
• GraphQL - querying and in-memory caching via apollo client; graphql-codegen to generate client query code
• Relay-style paginated queries

Backend stack:

• Python
• Flask
• Graphql via ariadne; Relay-style edges for pagination
• PostgreSQL - using SQLAlchemy for ORM and Alembic for migrations

Development

First, make sure you have venv

pip install venv

Create your virtual environment and source it

make venv
source venv/bin/activate

Install dependencies

make install

Compile typescript types for the web application

cd web && yarn run compile

Start the database

make dev-deps

Migrate to the latest version of the database (if you haven't already)

alembic upgrade head

Run the server in one terminal tab

make start-server

And run the React application in another

make start-web

Build

Build a docker container with the server, which also serves the SPA

make build

Debugging

FATAL: role "postgres" does not exist

Likely explanation: Postgres was installed via brew and doesn't have postgres configured as a superuser

Remediation: /usr/local/Cellar/postgresql/<version>/bin/createuser -s postgres

FATAL: no pg_hba.conf entry

Full error message: graphql.error.graphql_error.GraphQLError: (psycopg2.OperationalError) connection to server at "postgres" (172.18.0.2), port 5432 failed: FATAL: no pg_hba.conf entry for host "172.18.0.3", user "postgres", database "postgres", no encryption

Likely explanation: You're trying to launch the app via docker compose and pb_hba.confg is blocking connections from the server service to the postgres service

Remediation: add the following line to the bottom of ~/.postgres/data/pg_hba.conf: host postgres postgres 172.18.0.0/16 trust