I’m working to containerize a Golang app using Docker, and I’m running into an issue with getting the executable to build from my Dockerfile.

Here is the Dockerfile:

# syntax=docker/dockerfile:1

FROM golang:1.22.2

WORKDIR /app

# Download Go modules
COPY go.mod go.sum ./
RUN go mod download

COPY *.go ./

RUN CGO_ENABLED=0 GOOS=linux go build -o /sac

EXPOSE 8080

# Run
CMD ["/sac"]

Pretty much ripped straight from the Docker documentation on building Go images. When I go to build this (docker build --tag sac-server .), I run into a bunch off errors that all look like this:

main.go:10:2: no required module provides package github.com/GenerateNU/sac/backend/config; to add it:
go get github.com/GenerateNU/sac/backend/config

I get a bunch of these for various modules in our package. The full project’s name (defined in the (go.mod) is module github.com/GenerateNU/sac/backend, and in this example /config is a sub-package. Our directory looks like this:

backend
--->auth
--->config
--->constants
--->database
---><a bunch of other modules>
--->go.mod
--->go.sum
--->main.go
--->Dockerfile

And all the errors we’re getting about ‘no required modules’ are submodules/packages referenced the main.go.

How do I go about fixing this? I’ve tried replacing the go mod download with go get -d -v . and go mod tidy, but I get the same errors. Thank you! In case I didn’t provide enough info about our codebase, you can check out our repo link here: https://github.com/generateNU/sac