Why does "go build" fail for my Docker project?

Question

I have a npm binary I'd like to package up in a Docker container. I have this configuration:

# Docker image for the Mongo Stitch command

FROM golang:alpine

# Do a system update
RUN apk update

RUN apk add git

# Declare base dir
WORKDIR /root

# The console binary for Mongo Stitch
RUN git clone https://github.com/10gen/stitch-cli.git

WORKDIR /root/stitch-cli

RUN go build

CMD ["/bin/sh"]

I get this error:

main.go:8:2: cannot find package "github.com/10gen/stitch-cli/commands" in any of:
    /usr/local/go/src/github.com/10gen/stitch-cli/commands (from $GOROOT)
    /go/src/github.com/10gen/stitch-cli/commands (from $GOPATH)
main.go:9:2: cannot find package "github.com/10gen/stitch-cli/utils" in any of:
    /usr/local/go/src/github.com/10gen/stitch-cli/utils (from $GOROOT)
    /go/src/github.com/10gen/stitch-cli/utils (from $GOPATH)
main.go:11:2: cannot find package "github.com/mitchellh/cli" in any of:
    /usr/local/go/src/github.com/mitchellh/cli (from $GOROOT)
    /go/src/github.com/mitchellh/cli (from $GOPATH)

This is unexpected, since I imagine the official Go container would have everything I need. I have these vars set:

~ # set | grep GO
GOLANG_VERSION='1.11.5'
GOPATH='/go'

The build instructions say that go build is sufficient to get this working. I have played with go get, with various error outputs, but I think this might be a wild goose chase, since if I had to fetch dependencies manually the instructions would have said so.

For what it's worth though, if I do issue a go get in the container shell, I get this:

~/stitch-cli # go get
go get: no install location for directory /root/stitch-cli outside GOPATH
    For more details see: 'go help gopath'

I've tried parsing the material in said help file, but I am not sure what part applies to my case.

So, I wondered if missing GOROOT was worth fixing. I did this:

~/stitch-cli # which go
/usr/local/go/bin/go
~/stitch-cli # GOROOT=/usr/local/go
~/stitch-cli # export GOROOT
~/stitch-cli # go build
# _/root/stitch-cli
./main.go:25:3: cannot use commands.NewWhoamiCommandFactory(ui) (type "github.com/10gen/stitch-cli/vendor/github.com/mitchellh/cli".CommandFactory) as type "github.com/mitchellh/cli".CommandFactory in map value
./main.go:26:3: cannot use commands.NewLoginCommandFactory(ui) (type "github.com/10gen/stitch-cli/vendor/github.com/mitchellh/cli".CommandFactory) as type "github.com/mitchellh/cli".CommandFactory in map value
./main.go:27:3: cannot use commands.NewLogoutCommandFactory(ui) (type "github.com/10gen/stitch-cli/vendor/github.com/mitchellh/cli".CommandFactory) as type "github.com/mitchellh/cli".CommandFactory in map value
./main.go:28:3: cannot use commands.NewExportCommandFactory(ui) (type "github.com/10gen/stitch-cli/vendor/github.com/mitchellh/cli".CommandFactory) as type "github.com/mitchellh/cli".CommandFactory in map value
./main.go:29:3: cannot use commands.NewImportCommandFactory(ui) (type "github.com/10gen/stitch-cli/vendor/github.com/mitchellh/cli".CommandFactory) as type "github.com/mitchellh/cli".CommandFactory in map value
~/stitch-cli # 

OK, maybe this is a bit further, but I am now firmly in "trying random things" territory. Is there something I can do to have it work out of the box?

I also tried ordinary Alpine (v3.9) with Go manually installed, and that did not even have GOPATH set, but I got much the same "cannot find package" errors. What could I try next to get this to compile?

I have also tried switching to the full-fat version of the Golang image, rather than this lighter Alpine image, and I get the same issues, both with build and get.

I could also go back to installing via NPM, but I had problems with that (and that issue would probably be out of scope of a Golang question).

Possible duplicate

My question has been identified as a possible duplicate of this question. I think that question is essentially a duplicate of the secondary problem noted here, which as I mentioned earlier, was probably a red herring. If there are any dups detailing an answer to the first error, that would likely be a better signpost.

Answer 1

Flimzy kindly pointed me to another answer (which I would never have found without knowledgeable assistance). Since I think the build process is non-trivial, especially for non-Gophers such as myself, I will post the new Dockerfile:

# Docker image for the Mongo Stitch command

FROM golang:alpine

# Do a system update
RUN apk update

RUN apk add git curl

# Declare base dir
WORKDIR /root/src

RUN git clone https://github.com/10gen/stitch-cli.git

WORKDIR /root/src/stitch-cli

# Remove the old dependencies
RUN rm -rf vendor

# Fetch the dependencies
RUN curl https://raw.githubusercontent.com/golang/dep/master/install.sh | sh
RUN GOPATH=$GOPATH:/root dep ensure

# Now it should build
RUN GOPATH=$GOPATH:/root go build

CMD ["/bin/sh"]

The fetching of the dependencies results in this error:

Warning: the following project(s) have [[constraint]] stanzas in Gopkg.toml:

  ✗  github.com/10gen/escaper
  ✗  github.com/dgrijalva/jwt-go
  ✗  github.com/ogier/pflag
  ✗  gopkg.in/mgo.v2

However, these projects are not direct dependencies of the current project:
they are not imported in any .go files, nor are they in the 'required' list in
Gopkg.toml. Dep only applies [[constraint]] rules to direct dependencies, so
these rules will have no effect.

Either import/require packages from these projects so that they become direct
dependencies, or convert each [[constraint]] to an [[override]] to enforce rules
on these projects, if they happen to be transitive dependencies.

However, it still seems to compile. My worry is that I have had to do far more steps than are in the documentation, which leads me to think that I have made this more complicated than it needs to be.

Docker repo

I have made my Docker repo permanently available here.