configure entrypoint to create_db on startup of flask service via doc…

…ker-compose

.env.dev-sample

@@ -1,13 +1,15 @@
 # Flask
 FLASK_APP=project/__init__.py
 FLASK_ENV=development
-# db is a specific reference to the service in the docker-compose.yml file
-DATABASE_URL=postgresql://<user>:<password>@db:5432/<db>
 
 # Postgres
 POSTGRES_USER=<user>
 POSTGRES_PASSWORD=<password>
 POSTGRES_DB=<db>
-SQL_HOST=<db>
+SQL_HOST=db
 SQL_PORT=5432
-DATABASE=postgres
+DATABASE=postgres
+
+# SQLAlchemy
+# db is a specific reference to the service in the docker-compose.yml file
+DATABASE_URL=postgresql://<POSTGRES_USER>:<POSTGRES_PASSWORD>@<SQL_HOST>:5432/<POSTGRES_DB>

services/web/Dockerfile

@@ -8,10 +8,16 @@ WORKDIR /usr/src/app
 ENV PYTHONDONTWRITEBYTECODE 1
 ENV PYTHONUNBUFFERED 1
 
-# install dependencies
+# install system dependencies
+RUN apt-get update && apt-get install -y netcat
+
+# install app dependencies
 RUN pip install --upgrade pip
 COPY ./requirements.txt /usr/src/app/requirements.txt
 RUN pip install -r requirements.txt
 
 # copy project
-COPY . /usr/src/app/
+COPY . /usr/src/app/
+
+# run entrypoint.sh
+ENTRYPOINT ["/usr/src/app/entrypoint.sh"]

services/web/entrypoint.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+# Verify Postgres is up and healthy
+# Note: File permissions requirement
+# - chmod +x services/web/entrypoint.sh
+if [ "$DATABASE" = "postgres" ]
+then
+    echo "Waiting for postgres..."
+
+    while ! nc -z $SQL_HOST $SQL_PORT; do
+      sleep 0.1
+    done
+
+    echo "PostgreSQL started"
+fi
+
+python manage.py create_db
+
+exec "$@"