How to run go server on docker from binary - docker

Question

I have been trying to make a Dockerfile, that would let me build my go server as binary and then run it either from the scratch image or alpine. The server works fine locally, on macOS 10.13.5, and I made it work when it wasn't from binary on Docker.
I keep getting this error:
standard_init_linux.go:190: exec user process caused "exec format error"
I have been googling around and found something about system architecture. I am not sure how to check if that is the error and/or how to fix it.
Any hints for debugging or possible fix are much appreciated.
My Dockerfile:
FROM golang:1.10.3 as builder
WORKDIR /go/src/gitlab.com/main/server
COPY . .
RUN go get -d -v ./...
RUN CGO_ENABLED=0 GOOS=linux go build -a -o main .
FROM scratch
ADD main /
CMD ["/main"]
The output:
Building go
Step 1/9 : FROM golang:1.10.3 as builder
---> 4e611157870f
Step 2/9 : WORKDIR /go/src/gitlab.com/main/server
Removing intermediate container 20cd4d66008b
---> 621d9fc02dde
Step 3/9 : COPY . .
---> cab639571baf
Step 4/9 : RUN go get -d -v ./...
---> Running in 7681f9adc7b2
Removing intermediate container 7681f9adc7b2
---> 767a4c9dfb94
Step 5/9 : RUN go build -a -installsuffix cgo -o main .
---> Running in a6ec73121163
Removing intermediate container a6ec73121163
---> b9d7d1c0d2f9
Step 6/9 : FROM alpine:latest
---> 11cd0b38bc3c
Step 7/9 : WORKDIR /app
---> Using cache
---> 6d321d334b8f
Step 8/9 : COPY . .
---> 048a59fcdd8f
Step 9/9 : CMD ["/app/main"]
---> Running in d50d174644ff
Removing intermediate container d50d174644ff
---> 68f8f3c6cdf7
Successfully built 68f8f3c6cdf7
Successfully tagged main_go:latest
Creating go ... done
Attaching to go
go | standard_init_linux.go:190: exec user process caused "exec format error"
go exited with code 1

Answer 1

As #tgogos pointed out did I need to use what I build in the first step.
My final Dockerfile ended like this with a few further improvements: The important part is second last line though:
FROM golang:1.10.3 AS build
WORKDIR /go/src/gitlab.com/main/server
COPY . .
RUN go get github.com/golang/dep/cmd/dep && \
dep ensure && \
rm -f schema/bindata.go && \
go generate ./schema
RUN CGO_ENABLED=0 GOOS=linux go build -a -o main .
FROM alpine
RUN apk add --no-cache ca-certificates
COPY --from=build /go/src/gitlab.com/main/server/main .
CMD ["/main"]