Pin base python package requirements

- Require invoke to be installed before we can run "invoke update"

docker/Dockerfile

@@ -72,9 +72,9 @@ RUN apk add --no-cache git make bash \
     # MySQL/MariaDB support
     mariadb-connector-c mariadb-dev mariadb-client
 
-# Install required python packages
-RUN pip install --no-cache-dir -U psycopg2 mysqlclient pgcli mariadb
-
+# Install required base-level python packages
+COPY requirements.txt requirements.txt
+RUN pip install --no-cache-dir -U -r requirements.txt
 FROM base as production
 
 # Clone source code

docker/requirements.txt

@@ -0,0 +1,13 @@
+# Base python requirements for docker containers
+
+# Basic package requirements
+setuptools>=57.4.0
+wheel>=0.37.0
+invoke>=1.4.0                   # Invoke build tool
+gunicorn>=20.1.0                # Gunicorn web server
+
+# Database links
+psycopg2>=2.9.1
+mysqlclient>=2.0.3
+pgcli>=3.1.0
+mariadb>=1.0.7

requirements.txt

@@ -1,9 +1,3 @@
-# Basic package requirements
-setuptools>=57.4.0
-wheel>=0.37.0
-invoke>=1.4.0                   # Invoke build tool
-gunicorn>=20.1.0                # Gunicorn web server
-
 # Django framework
 Django==3.2.4                   # Django package