Add support to package install with pip.

Dockerfile

@@ -8,6 +8,7 @@ ARG RUNDIR
 ARG ENTRYPOINT=/usr/local/bin/lnls-run
 ARG RUNTIME_PACKAGES
 ARG RUNTIME_TAR_PACKAGES
+ARG RUNTIME_PIP_PACKAGES
 
 RUN apt update -y && \
     apt install -y --no-install-recommends \
@@ -24,6 +25,11 @@ COPY --from=build-image /usr/local/lib /usr/local/lib
 COPY --from=build-image /usr/local/bin/lnls-get-n-unpack /usr/local/bin/lnls-get-n-unpack
 RUN lnls-get-n-unpack -r $RUNTIME_TAR_PACKAGES && \
     ldconfig
+RUN if [ -n "$RUNTIME_PIP_PACKAGES" ]; then \
+        apt update && \
+        apt install -y --no-install-recommends pip && \
+        pip install $RUNTIME_PIP_PACKAGES; \
+    fi
 
 COPY --from=build-image /usr/local/bin/lnls-run /usr/local/bin/lnls-run
 
@@ -44,12 +50,18 @@ FROM build-image AS build-stage
 ARG REPONAME
 ARG BUILD_PACKAGES
 ARG BUILD_TAR_PACKAGES
+ARG BUILD_PIP_PACKAGES
 
 RUN if [ -n "$BUILD_PACKAGES" ]; then \
         apt update && \
         apt install -y --no-install-recommends $BUILD_PACKAGES; \
     fi
 RUN lnls-get-n-unpack -r $BUILD_TAR_PACKAGES
+RUN if [ -n "$BUILD_PIP_PACKAGES" ]; then \
+        apt update && \
+        apt install -y --no-install-recommends pip && \
+        pip install $BUILD_PIP_PACKAGES; \
+    fi
 
 WORKDIR /opt/${REPONAME}
 

README.md

@@ -65,8 +65,9 @@ stages even when they are not needed.
 Additional build and runtime packages to be installed can be listed in `args`,
 under the `BUILD_PACKAGES` and `RUNTIME_PACKAGES` keys, respectively. It is not
 necessary to quote them - e.g. `BUILD_PACKAGES: python3 python3-requests`.
-Packages essential to all (or most) IOCs should be added to [this repository's
-`Dockerfile`](./Dockerfile).
+Packages that strictly need to be installed via pip can be listed under the
+`BUILD_PIP_PACKAGES` and `RUNTIME_PIP_PACKAGES` keys. Packages essential to all
+(or most) IOCs should be added to [this repository's `Dockerfile`](./Dockerfile).
 
 The template above assumes the containers will be uploaded to the GitHub
 registry.