error 'build constraints exclude all Go files' when performing: go run controller-gen/main.go on golang1.12 container

[RamLavi]

I am getting the following error when my container (base image is FROM golang:1.12.0 or 1.12.+) performs the following command via one of the Makefile sections: go run vendor/sigs.k8s.io/controller-tools/cmd/controller-gen/main.go crd. The error I get is:

go run vendor/sigs.k8s.io/controller-tools/cmd/controller-gen/main.go crd
-: build constraints exclude all Go files in /go/src/github.com/k8snetworkplumbingwg/kubemacpool
Error: not all generators ran successfully
run `controller-gen crd -w` to see all available markers, or `controller-gen crd -h` for usage
exit status 1

(btw if I change the image back to golang 1.11.9 then the issue does not occur.)

I think the issue is related to the fact that controller-gen is installed via build constraint //+build, as this was insinuated in the following links: golang/go#31661 and golang/go#29268 (comment).

Do you have any idea how to handle it?

Environment:

GOARCH="amd64"
GOBIN=""
GOCACHE="/.cache/go-build"
GOEXE=""
GOFLAGS="-mod=vendor"
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/go/src/github.com/k8snetworkplumbingwg/kubemacpool/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build569404837=/tmp/go-build -gno-record-gcc-switches"

Go Version:
go version go1.12.15 linux/amd64

[RamLavi]

well, this seemed to do the trick:

go run vendor/sigs.k8s.io/controller-tools/cmd/controller-gen/main.go crd rbac:roleName=kubemacpool paths=./pkg/... output:crd:dir=config/ output:stdout

[cnfatal]

ensure file hack/tools.go content, there must a new empty line after the// +build tools comment

// +build tools

/*
...license...
*/

// This package imports things required by build scripts, to force `go mod` to see them as dependencies
package tools

import _ "k8s.io/code-generator"

not

// +build tools
package tools

import _ "k8s.io/code-generator"

IDK why, but it's works ...