diff --git a/Dockerfile.diagnostics b/Dockerfile.diagnostics
index 83bc6621..9d1bba2c 100644
--- a/Dockerfile.diagnostics
+++ b/Dockerfile.diagnostics
@@ -2,6 +2,6 @@ ARG version=3.8
 FROM python:${version}
 
 WORKDIR /workspace
-COPY setup.py README.rst ./
-RUN pip install -e .
-COPY . .
+COPY core core
+RUN pip install --no-cache-dir -e core
+COPY diagnostics.py .