Change container identifier to an ARG
-# Allow deploying the latest version for development.
-# hadolint ignore=DL3007
-FROM gcr.io/oak-ci/oak-functions:latest
+# Use an argument to specify base image containing the Oak Functions loader.
+# Default to using the latest version for development.
+ARG base_image=gcr.io/oak-ci/oak-functions:latest
+# hadolint ignore=DL3006
+FROM ${base_image}
COPY ./bin/weather_lookup.wasm /module.wasm
COPY ./config.toml /config.toml
