Distinguish between POSTGRES_DB and POSTGRES_USER

Closes #1301.

docs/developing-locally-docker.rst

@@ -113,10 +113,11 @@ Consider the aforementioned ``.envs/.local/.postgres``: ::
 
     # PostgreSQL
     # ------------------------------------------------------------------------------
+    POSTGRES_DB=<your project slug>
     POSTGRES_USER=XgOWtQtJecsAbaIyslwGvFvPawftNaqO
     POSTGRES_PASSWORD=jSljDz4whHuwO3aJIgVBrqEml5Ycbghorep4uVJ4xjDYQu0LfuTZdctj7y0YcCLu
 
-The two envs we are presented with here are ``POSTGRES_USER``, and ``POSTGRES_PASSWORD`` (by the way, their values have also been generated for you). You might have figured out already where these definitions will end up; it's all the same with ``django`` and ``caddy`` service container envs.
+The three envs we are presented with here are ``POSTGRES_DB``, ``POSTGRES_USER``, and ``POSTGRES_PASSWORD`` (by the way, their values have also been generated for you). You might have figured out already where these definitions will end up; it's all the same with ``django`` and ``caddy`` service container envs.
 
 
 Tips & Tricks

{{cookiecutter.project_slug}}/.envs/.local/.postgres

@@ -1,4 +1,5 @@
 # PostgreSQL
 # ------------------------------------------------------------------------------
+POSTGRES_DB={{ cookiecutter.project_slug }}
 POSTGRES_USER=!!!SET POSTGRES_USER!!!
 POSTGRES_PASSWORD=!!!SET POSTGRES_PASSWORD!!!

{{cookiecutter.project_slug}}/.envs/.production/.postgres

@@ -1,4 +1,5 @@
 # PostgreSQL
 # ------------------------------------------------------------------------------
+POSTGRES_DB={{ cookiecutter.project_slug }}
 POSTGRES_USER=!!!SET POSTGRES_USER!!!
 POSTGRES_PASSWORD=!!!SET POSTGRES_PASSWORD!!!

{{cookiecutter.project_slug}}/compose/production/django/entrypoint.sh

@@ -2,45 +2,47 @@
 
 set -o errexit
 set -o pipefail
-
+set -o nounset
-# todo: turn on after #1295
-# set -o nounset
 
 
 cmd="$@"
 
-# This entrypoint is used to play nicely with the current cookiecutter configuration.
-# Since docker-compose relies heavily on environment variables itself for configuration, we'd have to define multiple
-# environment variables just to support cookiecutter out of the box. That makes no sense, so this little entrypoint
-# does all this for us.
 export REDIS_URL=redis://redis:6379
+{%- if cookiecutter.use_celery == 'y' %}
+export CELERY_BROKER_URL="${REDIS_URL}/0"
+{%- endif %}
 
+if [ -z "${POSTGRES_USER}" ]; then
     # the official postgres image uses 'postgres' as default user if not set explictly.
-if [ -z "$POSTGRES_USER" ]; then
     export POSTGRES_USER=postgres
 fi
-
+export DATABASE_URL="postgres://${POSTGRES_USER}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB}"
-export DATABASE_URL=postgres://$POSTGRES_USER:$POSTGRES_PASSWORD@postgres:5432/$POSTGRES_USER
-{% if cookiecutter.use_celery == 'y' %}
-export CELERY_BROKER_URL=$REDIS_URL/0
-{% endif %}
 
 postgres_ready() {
 python << END
 import sys
+
 import psycopg2
+
 try:
-    conn = psycopg2.connect(dbname="$POSTGRES_USER", user="$POSTGRES_USER", password="$POSTGRES_PASSWORD", host="postgres")
+    psycopg2.connect(
+        dbname="${POSTGRES_DB}",
+        user="${POSTGRES_USER}",
+        password="${POSTGRES_PASSWORD}",
+        host="postgres"
+    )
 except psycopg2.OperationalError:
     sys.exit(-1)
 sys.exit(0)
+
 END
 }
 
 until postgres_ready; do
-  >&2 echo "Postgres is unavailable - sleeping"
+  >&2 echo 'PostgreSQL is unavailable (sleeping)...'
   sleep 1
 done
 
->&2 echo "Postgres is up - continuing..."
+>&2 echo 'PostgreSQL is up - continuing...'
+
 exec $cmd