How to get mod path in code

[dfang]

What version of Go are you using (go version)?

$ go version
go version go1.12.1 darwin/amd64

Does this issue reproduce with the latest release?

yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/mj/Library/Caches/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/mj/go"
GOPROXY="https://goproxy.io"
GORACE=""
GOROOT="/usr/local/Cellar/go/1.12.1/libexec"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.12.1/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
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 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/xb/dsd0_2b92x7bsl92xlzj6fbm0000gn/T/go-build222988675=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

What did you expect to see?

What did you see instead?

What i want to do ?

i want to RegisterViewPath in sub project, see this link

admin.RegisterViewPath("github.com/qor/admin/views")

this works when i don't use go mod (only go get in project root)

but if i use go.mod, when i run go run main.go in qor-example(import qor/admin)

i will get panic error,

2019/06/02 13:03:26 "GET http://localhost:7000/admin HTTP/1.1" from [::1]:57001 - panic: runtime error: invalid memory address or nil pointer dereference

because templates can't be found.

i know go mod is stored in $GOPATH/pkg/github.com/qor/admin@<hash_version>, how can i get that path in code ?

and how do i the project is running in go mod mode, because i don't want to break that.

in short, i want to add mod support like this

if (RUNNING_IN_GO_MOD_MODE) {
    admin.RegisterViewPath("$GOPATH/pkg/mod/github.com/qor/admin@<hash_version>/views")
} else {
    admin.RegisterViewPath("github.com/qor/admin/views")
}

[bcmills]

There is no programmatic way to do this today. See #3035 for a related feature request.