001. Go dev setup

GO Dev setup

GOPATH:

• lists places to look for go code also used to resolve go imports.
• default location: $HOME/go

• $ go env GOPATH
  /home/tan/go

• $ ls -1 $(go env GOPATH)
  bin
  pkg
  src

• src:
  • Holds the source code.
  • Path below src determines the import path or executable name.
• pkg:
  • Holds installed package objects.
  • Each targeting os and arch has its own subdirectory of pkg (pkg/GOOS_GOARCH)

  • $ go env GOOS GOARCH
    linux
    amd64

  • Suppose our GOPATH is /home/tan/go, a package with source $GOPATH/src/foo/bar can be imported as "foo/bar" and has its compiled form installed to "GOPATH/pkg/GOOS_GOARCH/foo/bar.a"

-bin:

• Holds compiled commands.

• Each command is named by its source directory(final element, not the entire path).

  • So $GOPATH/src/foo/quux is installed into $GOPATH/bin/quux not $GOPATH/bin/foo/quux

• GOBIN - $ go env GOBIN If the GOBIN environment variable is set, commands are installed to the directory it names instead of GOPATH/bin.

  • GOBIN must be an absolute path.

GOPATH=/home/tan/go

/home/tan/go/
    src/
        foo/
            bar/               (go code in package bar)
                x.go
            quux/              (go code in package main)
                y.go
    bin/
        quux                   (installed command)
    pkg/
        linux_amd64/
            foo/
                bar.a          (installed package object)

___________________________________________________________--- References:

• https://golang.org/cmd/go/#hdr-GOPATH_environment_variable