I’ve been using Go fulltime for ~9 months now.

The big differences I’ve noticed coming from Ruby:

Imports

Imports can’t clobber the global namespace or change the behavior of other packages (unless those packages were designed to allow it).

Only types/methods that are exported by a package are available when you import it.

Static language

There’s no monkey patching. When writing packages, export interfaces, not types (to make testing possible).

Composition, not inheritance

Go has no classes. Group data together using structs.

Any type can have methods. E.G.

type Foo string
func(f Foo) Print() { fmt.Println(f) }
Foo("a string").Print() # Prints "a string"

type Bar struct { str string }
func(b Bar) Print() { fmt.Println(b.str) }
Bar{"A different string"}.Print() # Prints "A different string"

Important differences moving from ruby to go:

• Code re-use via composition feels very natural coming from ruby.

• Where you would have used a module Foo in ruby, embed an interface Foo in go.

• Because imports can’t interfere with one another, many small dependencies is not a problem. Compose your app from many small frameworks rather than using one large one.

• Monitoring is back in the dark ages (No newrelic). Plan accordingly.