return to using a script for install_proxy

Dockerfile

@@ -57,8 +57,7 @@ COPY ioc ${SOURCE_FOLDER}/ioc
 RUN cd ${IOC} && ./install.sh && make
 
 # install runtime proxy for non-native builds
-RUN if [ EPICS_TARGET_ARCH != "linux_x86-64" ] ; then \
-    pip install rtems-proxy==0.2.2; fi
+RUN bash ${IOC}/install_proxy.sh
 
 ##### runtime preparation stage ################################################
 FROM developer AS runtime_prep

ioc/install_proxy.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+# This script installs a python proxy for the IOC.  The proxy is used to
+# communicate with the IOC from the kubernetes pod where the IOC is non-native
+# and cannot run in the cluster itself.
+
+# Only one proxy will be installed based on the EPICS_TARGET_ARCH
+# the entry point for all proxies will be "epics-proxy start" and will
+# be called by the default IOC start.sh script after it has prepared
+# runtime assets.
+# TODO: at present the rtems-proxy is the only supported proxy and uses
+# rtems-proxy start as its entry point.
+# TODO: consider renaming to ioc-proxy and genericizing. This would
+# negate the need for this script.
+
+# Most IOCs are native linux-x86_64 and will run directly in the cluster
+# so proxy installation is not required.
+
+if [[ $EPICS_TARGET_ARCH == "RTEMS-beatnik" ]] ; then
+    pip install rtems-proxy=="0.2.2"
+fi
+
+# no other proxies supported at present