architecture.md

The AbstractHandler

Interface

The AbstractHandler interface require three functions to be implemented

type AbstractHandler interface {
	Pipe(*sync.WaitGroup, chan<- content, <-chan int)
	Controller(ChannelHandlerFunc)
	ApiCallFunc(int) ([]int, *gitlab.Response, error)
}

The Pipe() function

The Pipe() function will instantiate the goroutines from inside genericHandler() function and requires three parameters.

• waitgroup pointer is used to mark goroutine itself as done when the Pipe() function ends.
• content channel is of type struct and is used as channel for the ChannelHandlerFunc (egress channel)
• int channel is used to get the current gitlab API call result page number. The page number is send from genericHandler() function.

To use the Pipe() function, you must interprete the int channel and put results into the content channel.

Example:

func (h MyHandler) Pipe(wg *sync.WaitGroup, output chan<- content, page <-chan int))
{
	defer wg.Done()
	for id := range page {
		res, _, err := gitlab.Get....(id)
		if err != nil {
			log.Fatal(err)
		}
		output <- content{
			Req:  "MyReq",
			ID:   res.ID,
		}
	}
}

The Controller() function

The Controller() function has only one Parameter: ChannelHandlerFunc and is called from function Run() in AbstractHandler.

• Parameter ChannelHandlerFunc is used to handle the results from the content channel.

The Controller() function can be used to implement your own handler (like genericHandler()). In most cases, you just call genericHandler() at the end of Controller(). If you don't want to call genericHandler() from Controller(), you have to implement your own "genericHandler" function which calls the ApiCallFunc() and Pipe()

Example:

func (h MyHandler) Controller(channelHandlerFunc ChannelHandlerFunc) {
	_, resp, err := gitlab.Users.ListUsers(&gitlab.ListOptions{})
	if err != nil {
		log.Fatal(err)
	}
	genericHandler(h, channelHandlerFunc, resp.TotalPages)
}

The ApiCallFunc() function

The ApiCallFunc() function has only one Parameter and returns three types.

• Parameter: int is used to get the current gitlab API call result Page number. The Page number is send from genericHandler() function.
• Return []int slice is used as ID array and needs to contains the gitlab API Call Response ID's (like UserID, RunnerID, ...).
• Return *gitlab.Response is the API Call response itself
• Return error is the API Call response error itself

Example:

func (h MyHandler) ApiCallFunc(page int) ([]int, *gitlab.Response, error) {
	opt := gitlab.UserListOptions{
        Page: page,
    }
    values, resp, err := gitlab.Users.ListUsers(&opt)

    // transfer result value into slice
	var xIds []int
	for _, value := range values {
		xIds = append(xIds, value.ID)
	}
	return xIds, resp, err
}