standardize actionloop Dockerfile build idiom (#115)
diff --git a/core/swift42Action/Dockerfile b/core/swift42Action/Dockerfile
index 94961d6..1e2bef1 100644
--- a/core/swift42Action/Dockerfile
+++ b/core/swift42Action/Dockerfile
@@ -14,10 +14,25 @@
# See the License for the specific language governing permissions and
# limitations under the License.
#
-FROM openwhisk/actionloop:nightly as builder
+
+# build go proxy from source
+FROM golang:1.12 AS builder_source
+RUN env CGO_ENABLED=0 go get github.com/apache/openwhisk-runtime-go/main && mv /go/bin/main /bin/proxy
+
+# or build it from a release
+FROM golang:1.12 AS builder_release
+ARG GO_PROXY_RELEASE_VERSION=1.12@1.15.0
+RUN curl -sL \
+ https://github.com/apache/openwhisk-runtime-go/archive/{$GO_PROXY_RELEASE_VERSION}.tar.gz\
+ | tar xzf -\
+ && cd openwhisk-runtime-go-*/main\
+ && GO111MODULE=on go build -o /bin/proxy
FROM swift:4.2
+# select the builder to use
+ARG GO_PROXY_BUILD_FROM=release
+
RUN rm -rf /var/lib/apt/lists/* && apt-get clean && apt-get update \
&& apt-get install -y --no-install-recommends locales python3 vim \
&& rm -rf /var/lib/apt/lists/* \
@@ -31,7 +46,9 @@
WORKDIR /swiftAction
-COPY --from=builder /bin/proxy /bin/proxy
+COPY --from=builder_source /bin/proxy /bin/proxy_source
+COPY --from=builder_release /bin/proxy /bin/proxy_release
+RUN mv /bin/proxy_${GO_PROXY_BUILD_FROM} /bin/proxy
ADD swiftbuild.py /bin/compile
ADD swiftbuild.py.launcher.swift /bin/compile.launcher.swift
COPY _Whisk.swift /swiftAction/Sources/
