Go – How does Go update third-party packages

Have a look at the docs for encoding/json.Marshal. It discusses using struct field tags to determine how the generated json is formatted.

For example:

type T struct {
    FieldA int    `json:"field_a"`
    FieldB string `json:"field_b,omitempty"`
}

This will generate JSON as follows:

{
    "field_a": 1234,
    "field_b": "foobar"
}

1. For the package newmath it's the same as (later 2.)

   $ mkdir $GOPATH/src/github.com/username/newmath
   $ cd $GOPATH/src/github.com/username/newmath
   $ git init
   $ ... more git setup
   $ touch sqrt.go
   $ gvim sqrt.go
   $ git add sqrt.go
   $ git commit -a -m 'Inital commit'
   $ git push
   

   Now people can do

   $ go get github.com/username/newmath
   

   and

   import "github.com/username/newmath"

   should now work in their sources. The package will be installed on demand automatically.

2. I'll assume that the hello command and the newmath package are not related, or not enough tightly related to belong to a single repository.

   $ mkdir $GOPATH/src/github.com/username/hello
   $ cd $GOPATH/src/github.com/username/hello
   $ git init
   $ ... more git setup
   $ touch hello.go
   $ gvim hello.go
   $ git add hello.go
   $ git commit -a -m 'Inital commit'
   $ git push
   

   Now people can do

   $ go get github.com/username/hello
   $ go install github.com/username/hello
   

   to install your command hello.

3. • It makes almost no sense to publish the content of $GOPATH/pkg at the hosting service.
   • It makes some sense to publish the content of $GOPATH/bin at the hosting service. But I discourage this practice for obvious reasons. Additionally, if you're publishing the sources - the binaries are not necessary and everybody can build their (trusted) own.

You seem to be perhaps still a bit confused by the term 'workspace'. A workspace is quite often existing only once at the developer's machine, yet it the typically contains several repositories. Some authored by the developer, others "go getted" from the Internet. To publish a whole wokspace in this case makes little sense.

However, there are people using a separate workspace per project or per repository or maybe even per package. I don't know what the benefits are. Or better said, I think that there are none compared to the single workspace, defined by, say export GOPATH=$HOME (as is my case for years w/o any trouble with it for years).