Refactor Dockerfile into a single file with targets to better support arm64

Author: pquerna

Dockerfile

@@ -2,7 +2,45 @@ ARG TARGET=server
 ARG GOPROXY
 
 ##### Temporal builder #####
-FROM temporalio/base-builder:1.2.0 AS temporal-builder
+FROM golang:1.16-alpine AS base-builder
+
+RUN apk add --update --no-cache \
+    make \
+    git \
+    protobuf \
+    build-base
+
+
+##### dockerize builder: built from source to support arm & x86 #####
+FROM base-builder AS dockerize-builder
+RUN mkdir -p /xsrc && \
+    git clone https://github.com/jwilder/dockerize.git && \
+    cd dockerize && \
+    go mod init github.com/jwilder/dockerize && \
+    go mod tidy && \
+    go build -o /usr/local/bin/dockerize .
+
+##### base server image #####
+FROM alpine:3.12 AS base-server
+
+RUN apk add --update --no-cache \
+    ca-certificates \
+    openssl \
+    bash \
+    curl \
+    vim
+
+# set up nsswitch.conf for Go's "netgo" implementation
+# https://github.com/gliderlabs/docker-alpine/issues/367#issuecomment-424546457
+RUN test ! -e /etc/nsswitch.conf && echo 'hosts: files dns' > /etc/nsswitch.conf
+COPY --from=dockerize-builder /usr/local/bin/dockerize /usr/local/bin/dockerize
+SHELL ["/bin/bash", "-c"]
+
+##### temporal-base-server target #####
+FROM base-server AS temporal-base-server
+
+##### temporal-builder target #####
+FROM base-builder AS temporal-builder
 
 WORKDIR /temporal
 
@@ -12,8 +50,8 @@ RUN go mod download
 COPY . .
 RUN make bins
 
-##### Temporal server #####
-FROM temporalio/base-server:1.0.0 AS temporal-server
+##### temporal-server target #####
+FROM temporal-base-server AS temporal-server
 WORKDIR /etc/temporal
 ENV TEMPORAL_HOME /etc/temporal
 ENV SERVICES "history:matching:frontend:worker"
@@ -48,13 +86,13 @@ CMD ["autosetup", "develop"]
 COPY docker/setup-develop.sh /etc/temporal/setup-develop.sh
 
 ##### Temporal CLI (tctl) #####
-FROM temporalio/base-server:1.0.0 AS temporal-tctl
+FROM temporal-base-server AS temporal-tctl
 WORKDIR /etc/temporal
 ENTRYPOINT ["tctl"]
 COPY --from=temporal-builder /temporal/tctl /usr/local/bin
 
 ##### Temporal admin tools #####
-FROM temporalio/base-admin-tools:1.0.0 as temporal-admin-tools
+FROM temporal-base-server as temporal-admin-tools
 WORKDIR /etc/temporal
 # Keep the container running.
 ENTRYPOINT ["tail", "-f", "/dev/null"]