delete.go

// Copyright (c) 2016 IBM Corp. All rights reserved.
// Use of this source code is governed by the Apache License,
// Version 2.0, a copy of which can be found in the LICENSE file.

// Delete a room

package main

import (
	"fmt"
	"net/http"
	"time"
)

// Deletes the room denoted by roomId from the GameOn! server, with retries
// on connection failure.
//
// An error will be returned if the deletion fails, otherwise nil will be returned.
func deleteWithRetries(client *http.Client, roomId string) (e error) {
	locus := "DELETE_W_RETRIES"
	checkpoint(locus, fmt.Sprintf("retries=%d secondsBetween=%d", config.retries, config.secondsBetween))

	for i := 0; i < config.retries; i++ {
		checkpoint(locus, fmt.Sprintf("Begin attempt %d of %d",
			i+1, config.retries))
		var stopTrying bool
		stopTrying, e = deleteRoom(client, roomId)
		if e == nil {
			if stopTrying {
				checkpoint(locus, fmt.Sprintf("Room deletion failed. Room _id=%s persists still.",
					roomId))
			} else {
				checkpoint(locus, fmt.Sprintf("Room deletion was successful. Room _id=%s should be gone.",
					roomId))
			}
			return
		}
		checkpoint(locus, fmt.Sprintf("sleeping %d seconds.", config.secondsBetween))
		if i+1 < config.retries {
			time.Sleep(time.Duration(config.secondsBetween) * time.Second)
		}
	}
	checkpoint(locus, "Room deletion failed.")
	e = RegError{fmt.Sprintf("Timed out. Last error: %s", e.Error())}
	return
}

// deleteRoom attempts to delete the room denoted by roomId from a Game On! server.
//
// The err return variable - When an error occurs, that error is returns via
// the err return variable, otherwise the err return variable will remain nil.
//
// The stopTrying return variable - Some errors are more permanent than others.
// For example, an authenticatino error will continue to fail regardless of how
// many times we try. Basic connection errors, however, may cause failure initially
// and then, later in time, we may succeed as our network connection gets better
// or the game server, which may have been temporarily out of service, comes back
// on line. To differentiate between the two, we will set the stopTrying return var
// to true when we feel that the deletion request, in its current form, will never
// be successful.
func deleteRoom(client *http.Client, roomId string) (stopTrying bool, err error) {
	locus := "DELETE.ROOM"
	checkpoint(locus, "Begin")
	u := fmt.Sprintf("%s://%s/map/v1/sites/%s",
		config.protocol, config.gameonAddr, roomId)
	checkpoint(locus, fmt.Sprintf("URL %s", u))

	req, err := http.NewRequest("DELETE", u, nil)
	if err != nil {
		checkpoint(locus, fmt.Sprintf("NewRequest.Error err=%s", err.Error()))
		return
	}

	addAuthenticationHeaders(req, "")

	resp, err := client.Do(req)
	if err != nil {
		checkpoint(locus, fmt.Sprintf("DELETE.Error err=%s", err.Error()))
		return
	}
	body, err := extractBody(resp)
	if err != nil {
		checkpoint(locus, fmt.Sprintf("Body.Error err=%s", err.Error()))
		return
	}
	checkpoint(locus, fmt.Sprintf("Status=%s", resp.Status))

	switch resp.StatusCode {
	case http.StatusNoContent:
		checkpoint(locus, "Deleted")
		return
	case http.StatusOK, http.StatusForbidden, http.StatusNotFound:
		checkpoint(locus, "Sigh. There is no use trying any more.")
		printResponseBody(locus, resp, body)
		stopTrying = true
		return
	default:
		err = RegError{fmt.Sprintf("Unhandled Status: %s", resp.Status)}
		checkpoint(locus, fmt.Sprintf("Unhandled Status=%s", resp.Status))
		printResponseBody(locus, resp, body)
		return
	}
}