１．uuidのv4を利用すために、google uuidのpkgをimportする

import "github.com/google/uuid"
...
// version4 NewRandom
_uuid , _ := uuid.NewRandom();
uuid := _uuid.String();

２．srcのbuild
pkgをimportしただけだと以下のbuild errorがでる

# sh build.sh
src/sample.go:22:2: cannot find package "github.com/google/uuid" in any of:
        /usr/lib/golang/src/github.com/google/uuid (from $GOROOT)
        /root/go/src/github.com/google/uuid (from $GOPATH)
# sh build.sh
src/sample.go:23:2: invalid import path: "uuid github.com/google/uuid"

３．pkgのinstall

# go get github.com/google/uuid

４．再度srcのbuild
build errorが出なくなる