docker: reduce images size

By introducing multi-stage build
And switching to alpine
And using grpcurl from docker

x20 size reduction !

$ docker images | grep smbios
ghcr.io/opiproject/opi-smbios-bridge   main            f5c93b419b0a   3 hours ago     1.55GB
opi-smbios-bridge                      main            dd66706d37d1   12 days ago     73.1MB

Signed-off-by: Boris Glimcher <[email protected]>

Dockerfile

@@ -1,23 +1,26 @@
-# syntax=docker/dockerfile:1
+# SPDX-License-Identifier: Apache-2.0
+# Copyright (c) 2022 Dell Inc, or its subsidiaries.
 
-# Alpine is chosen for its small footprint
-# compared to Ubuntu
-FROM docker.io/library/golang:1.19.4
+FROM docker.io/library/golang:1.19.4-alpine3.17 as builder
+RUN apk add --no-cache build-base
 
 WORKDIR /app
 
-# install curl (healthcheck)
-RUN go install github.com/fullstorydev/grpcurl/cmd/[email protected]
-
 # Download necessary Go modules
 COPY go.mod ./
 COPY go.sum ./
 RUN go mod download
 
 # build an app
 COPY *.go ./
-RUN go build -v -buildmode=plugin -o /opi-smbios-bridge.so ./inventory.go
+RUN go build -v -buildmode=plugin  -o /opi-smbios-bridge.so ./inventory.go \
+ && go build -v -buildmode=default -o /opi-smbios-bridge    ./main.go
 
+# second stage to reduce image size
+FROM alpine:3.17
+COPY --from=builder /opi-smbios-bridge /
+COPY --from=builder /opi-smbios-bridge.so /
+COPY --from=docker.io/fullstorydev/grpcurl:v1.8.7-alpine /bin/grpcurl /usr/local/bin/
 EXPOSE 50051
-CMD [ "go", "run", "main.go", "-port=50051" ]
-HEALTHCHECK CMD grpcurl -plaintext localhost:50051 list || exit 1
+CMD [ "/opi-smbios-bridge", "-port=50051" ]
+HEALTHCHECK CMD grpcurl -plaintext localhost:50051 list || exit 1