Multistage Docker build with scratch container

.dockerignore

@@ -0,0 +1,3 @@
+.git/
+tests/
+screenshot/

Dockerfile

@@ -1,10 +1,15 @@
-FROM alpine:3.4
+# Define build image which compiles binary
+FROM golang:1.9.2-alpine as build
 
-RUN apk update && \
-  apk add -U --no-cache \
-  ca-certificates \
-  openssh-client && \
-  rm -rf /var/cache/apk/*
+WORKDIR /go/src/github.com/appleboy/drone-ssh
+
+COPY . .
+
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -a -tags netgo \
+ && cp drone-ssh /bin
+
+# Define final image which consumes final artifact
+FROM scratch
 
 LABEL org.label-schema.version=latest
 LABEL org.label-schema.vcs-url="https://github.com/appleboy/drone-ssh.git"
@@ -12,5 +17,8 @@ LABEL org.label-schema.name="drone-ssh"
 LABEL org.label-schema.vendor="Bo-Yi Wu"
 LABEL org.label-schema.schema-version="1.0"
 
-ADD release/linux/amd64/drone-ssh /bin/
+COPY --from=build /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
+
+COPY --from=build /bin/drone-ssh /bin/
+
 ENTRYPOINT ["/bin/drone-ssh"]