func (m ByRank) Less(i, j int) bool {
if m.ClientInfo.IsValid() {
if m.ClientInfo.ASNum == m.Mirrors[i].Asnum {
if m.Mirrors[i].Asnum != m.Mirrors[j].Asnum {
return true
}
} else if m.ClientInfo.ASNum == m.Mirrors[j].Asnum {
return false
}
//TODO Simplify me
if m.ClientInfo.CountryCode != "" {
if utils.IsInSlice(m.ClientInfo.CountryCode, m.Mirrors[i].CountryFields) {
if !utils.IsInSlice(m.ClientInfo.CountryCode, m.Mirrors[j].CountryFields) {
return true
}
} else if utils.IsInSlice(m.ClientInfo.CountryCode, m.Mirrors[j].CountryFields) {
return false
}
} else if m.ClientInfo.ContinentCode != "" {
if m.ClientInfo.ContinentCode == m.Mirrors[i].ContinentCode {
if m.ClientInfo.ContinentCode != m.Mirrors[j].ContinentCode {
return true
}
} else if m.ClientInfo.ContinentCode == m.Mirrors[j].ContinentCode {
return false
}
}
return m.Mirrors[i].Distance < m.Mirrors[j].Distance
} else {
// Randomize the output if we miss client info
return rand.Intn(2) == 0
}
}
func (h DefaultEngine) Selection(ctx *Context, cache *mirrors.Cache, fileInfo *filesystem.FileInfo, clientInfo network.GeoIPRecord) (mlist mirrors.Mirrors, excluded mirrors.Mirrors, err error) {
// Get details about the requested file
*fileInfo, err = cache.GetFileInfo(fileInfo.Path)
if err != nil {
return
}
// Prepare and return the list of all potential mirrors
mlist, err = cache.GetMirrors(fileInfo.Path, clientInfo)
if err != nil {
return
}
// Filter
safeIndex := 0
excluded = make([]mirrors.Mirror, 0, len(mlist))
var closestMirror float32
var farthestMirror float32
for i, m := range mlist {
// Does it support http? Is it well formated?
if !strings.HasPrefix(m.HttpURL, "http://") && !strings.HasPrefix(m.HttpURL, "https://") {
m.ExcludeReason = "Invalid URL"
goto delete
}
// Is it enabled?
if !m.Enabled {
m.ExcludeReason = "Disabled"
goto delete
}
// Is it up?
if !m.Up {
if m.ExcludeReason == "" {
m.ExcludeReason = "Down"
}
goto delete
}
// Is it the same size as source?
if m.FileInfo != nil {
if m.FileInfo.Size != fileInfo.Size {
m.ExcludeReason = "File size mismatch"
goto delete
}
}
// Is it configured to serve its continent only?
if m.ContinentOnly {
if !clientInfo.IsValid() || clientInfo.ContinentCode != m.ContinentCode {
m.ExcludeReason = "Continent only"
goto delete
}
}
// Is it configured to serve its country only?
if m.CountryOnly {
if !clientInfo.IsValid() || !utils.IsInSlice(clientInfo.CountryCode, m.CountryFields) {
m.ExcludeReason = "Country only"
goto delete
}
}
// Is it in the same AS number?
if m.ASOnly {
if !clientInfo.IsValid() || clientInfo.ASNum != m.Asnum {
m.ExcludeReason = "AS only"
goto delete
}
}
if safeIndex == 0 {
closestMirror = m.Distance
} else if closestMirror > m.Distance {
closestMirror = m.Distance
}
if m.Distance > farthestMirror {
farthestMirror = m.Distance
}
mlist[safeIndex] = mlist[i]
safeIndex++
continue
delete:
excluded = append(excluded, m)
}
// Reduce the slice to its new size
mlist = mlist[:safeIndex]
if !clientInfo.IsValid() {
// Shuffle the list
//XXX Should we use the fallbacks instead?
for i := range mlist {
j := rand.Intn(i + 1)
mlist[i], mlist[j] = mlist[j], mlist[i]
}
// Shortcut
if !ctx.IsMirrorlist() {
// Reduce the number of mirrors to process
mlist = mlist[:utils.Min(5, len(mlist))]
}
return
}
// We're not interested in divisions by zero
if closestMirror == 0 {
closestMirror = math.SmallestNonzeroFloat32
}
/* Weight distribution for random selection [Probabilistic weight] */
// Compute score for each mirror and return the mirrors eligible for weight distribution.
// This includes:
// - mirrors found in a 1.5x (configurable) range from the closest mirror
// - mirrors targeting the given country (as primary or secondary)
// - mirrors being in the same AS number
totalScore := 0
baseScore := int(farthestMirror)
weights := map[string]int{}
for i := 0; i < len(mlist); i++ {
m := &mlist[i]
m.ComputedScore = baseScore - int(m.Distance) + 1
if m.Distance <= closestMirror*GetConfig().WeightDistributionRange {
score := (float32(baseScore) - m.Distance)
if !utils.IsPrimaryCountry(clientInfo, m.CountryFields) {
score /= 2
}
m.ComputedScore += int(score)
} else if utils.IsPrimaryCountry(clientInfo, m.CountryFields) {
m.ComputedScore += int(float32(baseScore) - (m.Distance * 5))
} else if utils.IsAdditionalCountry(clientInfo, m.CountryFields) {
m.ComputedScore += int(float32(baseScore) - closestMirror)
}
if m.Asnum == clientInfo.ASNum {
m.ComputedScore += baseScore / 2
}
floatingScore := float64(m.ComputedScore) + (float64(m.ComputedScore) * (float64(m.Score) / 100)) + 0.5
// The minimum allowed score is 1
m.ComputedScore = int(math.Max(floatingScore, 1))
if m.ComputedScore > baseScore {
// The weight must always be > 0 to not break the randomization below
totalScore += m.ComputedScore - baseScore
weights[m.ID] = m.ComputedScore - baseScore
}
}
// Get the final number of mirrors selected for weight distribution
selected := len(weights)
// Sort mirrors by computed score
sort.Sort(mirrors.ByComputedScore{mlist})
if selected > 1 {
if ctx.IsMirrorlist() {
// Don't reorder the results, just set the percentage
for i := 0; i < selected; i++ {
id := mlist[i].ID
for j := 0; j < len(mlist); j++ {
if mlist[j].ID == id {
mlist[j].Weight = float32(float64(weights[id]) * 100 / float64(totalScore))
break
}
}
}
} else {
// Randomize the order of the selected mirrors considering their weights
weightedMirrors := make([]mirrors.Mirror, selected)
rest := totalScore
for i := 0; i < selected; i++ {
var id string
rv := rand.Int31n(int32(rest))
s := 0
for k, v := range weights {
s += v
if int32(s) > rv {
id = k
break
}
}
for _, m := range mlist {
if m.ID == id {
m.Weight = float32(float64(weights[id]) * 100 / float64(totalScore))
weightedMirrors[i] = m
break
}
}
rest -= weights[id]
delete(weights, id)
}
// Replace the head of the list by its reordered counterpart
mlist = append(weightedMirrors, mlist[selected:]...)
// Reduce the number of mirrors to return
v := math.Min(math.Min(5, float64(selected)), float64(len(mlist)))
mlist = mlist[:int(v)]
}
} else if selected == 1 && len(mlist) > 0 {
mlist[0].Weight = 100
}
return
}