use envsubst to configure stuff in dagster.yaml

Dockerfile.system

@@ -1,8 +1,11 @@
+FROM python:3.12-slim
+
+# Install envsubst
+RUN apt-get update && apt-get install -y gettext
+
 # Dagster libraries to run both dagit and the dagster-daemon. Does not
 # need to have access to any pipeline code.
 
-FROM python:3.12-slim
-
 COPY dagster-requirements.txt requirements.txt
 
 RUN pip install uv
@@ -14,6 +17,20 @@ ENV DAGSTER_HOME=/opt/dagster/home/
 
 RUN mkdir -p $DAGSTER_HOME
 
-COPY dagster.yaml workspace.yaml $DAGSTER_HOME
+# COPY dagster.yaml workspace.yaml $DAGSTER_HOME
+
+# Create entrypoint that renders the dagster.yaml from a template
+RUN cat << 'EOF' > /entrypoint.sh
+#!/bin/sh
+set -e
+
+echo "Rendering dagster.yaml from template..."
+envsubst < dagster.yaml.template > dagster.yaml
+
+echo "Starting Dagster: $@"
+exec "$@"
+EOF
+RUN chmod +x /entrypoint.sh
+ENTRYPOINT ["/entrypoint.sh"]
 
 WORKDIR $DAGSTER_HOME