The events interface

events.go

// Package events is for event streaming
package events

// Events is an event streaming interface
type Events interface {
        // Stream returns a event stream by ID
        Stream(id string, ...StreamOption) Stream
}

// Stream represents an event stream
type Stream interface {
        // Read from the stream
        Read() (*Event, error)
        // Write to the stream
        Write(*Event) error
}

// Event is a single event sent or received on a stream
type Event struct {
        // Unique ID
        Id string
        // Timestamp of event
        Timestamp time.Time
        // Associated metadata
        Header map[string]string
        // Payload of the event
        Body []byte
}

type StreamOptions struct {
        // The offset at which to start reading from
        Offset time.Time
}

type StreamOption func(*StreamOptions) error

// WithOffset sets the offset from which to read
type WithOffset(t time.Time) StreamOption {
        return func(o *StreamOptions) error {
                o.Offset = t
        }
}

Can I ask a Qs re: the visibility of the StreamOptions struct?

When I personally use the "WithFunc" pattern, I generally keep the ***Options struct and its members private because only the package uses these values internally. The above looks the same in that the Events interface Stream func receives a variadic of StreamOption, so the OptionS is not used from outside callers.

Being public may be a better fit for calling code you have I'm not aware of, I'm just trying to better understand my own preference here to private vs public members and why public was chosen here. Thanks K

The use case here is that you'll then provide Options as a method on Stream so that you can actually access these and see whats set. Often you might be passing the interfaces around and you need to know what the setup is. If its private, its opaque. You basically lose the config. And if you want to create a new instance of something again, you don't have those values.

👍 Ok thanks makes sense - thanks for the time & response.