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model.go
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model.go
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package ring
import (
"container/heap"
"fmt"
"sort"
"time"
"github.com/gogo/protobuf/proto"
"github.com/cortexproject/cortex/pkg/ring/kv/codec"
"github.com/cortexproject/cortex/pkg/ring/kv/memberlist"
)
// ByAddr is a sortable list of IngesterDesc.
type ByAddr []IngesterDesc
func (ts ByAddr) Len() int { return len(ts) }
func (ts ByAddr) Swap(i, j int) { ts[i], ts[j] = ts[j], ts[i] }
func (ts ByAddr) Less(i, j int) bool { return ts[i].Addr < ts[j].Addr }
// ProtoDescFactory makes new Descs
func ProtoDescFactory() proto.Message {
return NewDesc()
}
// GetCodec returns the codec used to encode and decode data being put by ring.
func GetCodec() codec.Codec {
return codec.NewProtoCodec("ringDesc", ProtoDescFactory)
}
// NewDesc returns an empty ring.Desc
func NewDesc() *Desc {
return &Desc{
Ingesters: map[string]IngesterDesc{},
}
}
// AddIngester adds the given ingester to the ring. Ingester will only use supplied tokens,
// any other tokens are removed.
func (d *Desc) AddIngester(id, addr, zone string, tokens []uint32, state IngesterState, registeredAt time.Time) IngesterDesc {
if d.Ingesters == nil {
d.Ingesters = map[string]IngesterDesc{}
}
registeredTimestamp := int64(0)
if !registeredAt.IsZero() {
registeredTimestamp = registeredAt.Unix()
}
ingester := IngesterDesc{
Addr: addr,
Timestamp: time.Now().Unix(),
RegisteredTimestamp: registeredTimestamp,
State: state,
Tokens: tokens,
Zone: zone,
}
d.Ingesters[id] = ingester
return ingester
}
// RemoveIngester removes the given ingester and all its tokens.
func (d *Desc) RemoveIngester(id string) {
delete(d.Ingesters, id)
}
// ClaimTokens transfers all the tokens from one ingester to another,
// returning the claimed token.
// This method assumes that Ring is in the correct state, 'to' ingester has no tokens anywhere.
// Tokens list must be sorted properly. If all of this is true, everything will be fine.
func (d *Desc) ClaimTokens(from, to string) Tokens {
var result Tokens
if fromDesc, found := d.Ingesters[from]; found {
result = fromDesc.Tokens
fromDesc.Tokens = nil
d.Ingesters[from] = fromDesc
}
ing := d.Ingesters[to]
ing.Tokens = result
d.Ingesters[to] = ing
return result
}
// FindIngestersByState returns the list of ingesters in the given state
func (d *Desc) FindIngestersByState(state IngesterState) []IngesterDesc {
var result []IngesterDesc
for _, ing := range d.Ingesters {
if ing.State == state {
result = append(result, ing)
}
}
return result
}
// Ready returns no error when all ingesters are active and healthy.
func (d *Desc) Ready(now time.Time, heartbeatTimeout time.Duration) error {
numTokens := 0
for id, ingester := range d.Ingesters {
if now.Sub(time.Unix(ingester.Timestamp, 0)) > heartbeatTimeout {
return fmt.Errorf("instance %s past heartbeat timeout", id)
} else if ingester.State != ACTIVE {
return fmt.Errorf("instance %s in state %v", id, ingester.State)
}
numTokens += len(ingester.Tokens)
}
if numTokens == 0 {
return fmt.Errorf("no tokens in ring")
}
return nil
}
// TokensFor return all ring tokens and tokens for the input provided ID.
// Returned tokens are guaranteed to be sorted.
func (d *Desc) TokensFor(id string) (myTokens, allTokens Tokens) {
allTokens = d.GetTokens()
myTokens = d.Ingesters[id].Tokens
return
}
// GetRegisteredAt returns the timestamp when the instance has been registered to the ring
// or a zero value if unknown.
func (i *IngesterDesc) GetRegisteredAt() time.Time {
if i == nil || i.RegisteredTimestamp == 0 {
return time.Time{}
}
return time.Unix(i.RegisteredTimestamp, 0)
}
func (i *IngesterDesc) IsHealthy(op Operation, heartbeatTimeout time.Duration, now time.Time) bool {
healthy := op.IsInstanceInStateHealthy(i.State)
return healthy && now.Unix()-i.Timestamp <= heartbeatTimeout.Milliseconds()/1000
}
// Merge merges other ring into this one. Returns sub-ring that represents the change,
// and can be sent out to other clients.
//
// This merge function depends on the timestamp of the ingester. For each ingester,
// it will choose more recent state from the two rings, and put that into this ring.
// There is one exception: we accept LEFT state even if Timestamp hasn't changed.
//
// localCAS flag tells the merge that it can use incoming ring as a full state, and detect
// missing ingesters based on it. Ingesters from incoming ring will cause ingester
// to be marked as LEFT and gossiped about.
//
// If multiple ingesters end up owning the same tokens, Merge will do token conflict resolution
// (see resolveConflicts).
//
// This method is part of memberlist.Mergeable interface, and is only used by gossiping ring.
func (d *Desc) Merge(mergeable memberlist.Mergeable, localCAS bool) (memberlist.Mergeable, error) {
return d.mergeWithTime(mergeable, localCAS, time.Now())
}
func (d *Desc) mergeWithTime(mergeable memberlist.Mergeable, localCAS bool, now time.Time) (memberlist.Mergeable, error) {
if mergeable == nil {
return nil, nil
}
other, ok := mergeable.(*Desc)
if !ok {
// This method only deals with non-nil rings.
return nil, fmt.Errorf("expected *ring.Desc, got %T", mergeable)
}
if other == nil {
return nil, nil
}
thisIngesterMap := buildNormalizedIngestersMap(d)
otherIngesterMap := buildNormalizedIngestersMap(other)
var updated []string
for name, oing := range otherIngesterMap {
ting := thisIngesterMap[name]
// ting.Timestamp will be 0, if there was no such ingester in our version
if oing.Timestamp > ting.Timestamp {
oing.Tokens = append([]uint32(nil), oing.Tokens...) // make a copy of tokens
thisIngesterMap[name] = oing
updated = append(updated, name)
} else if oing.Timestamp == ting.Timestamp && ting.State != LEFT && oing.State == LEFT {
// we accept LEFT even if timestamp hasn't changed
thisIngesterMap[name] = oing // has no tokens already
updated = append(updated, name)
}
}
if localCAS {
// This breaks commutativity! But we only do it locally, not when gossiping with others.
for name, ting := range thisIngesterMap {
if _, ok := otherIngesterMap[name]; !ok && ting.State != LEFT {
// missing, let's mark our ingester as LEFT
ting.State = LEFT
ting.Tokens = nil
// We are deleting entry "now", and should not keep old timestamp, because there may already be pending
// message in the gossip network with newer timestamp (but still older than "now").
// Such message would "resurrect" this deleted entry.
ting.Timestamp = now.Unix()
thisIngesterMap[name] = ting
updated = append(updated, name)
}
}
}
// No updated ingesters
if len(updated) == 0 {
return nil, nil
}
// resolveConflicts allocates lot of memory, so if we can avoid it, do that.
if conflictingTokensExist(thisIngesterMap) {
resolveConflicts(thisIngesterMap)
}
// Let's build a "change" for returning
out := NewDesc()
for _, u := range updated {
ing := thisIngesterMap[u]
out.Ingesters[u] = ing
}
d.Ingesters = thisIngesterMap
return out, nil
}
// MergeContent describes content of this Mergeable.
// Ring simply returns list of ingesters that it includes.
func (d *Desc) MergeContent() []string {
result := []string(nil)
for k := range d.Ingesters {
result = append(result, k)
}
return result
}
// buildNormalizedIngestersMap will do the following:
// - sorts tokens and removes duplicates (only within single ingester)
// - it doesn't modify input ring
func buildNormalizedIngestersMap(inputRing *Desc) map[string]IngesterDesc {
out := map[string]IngesterDesc{}
// Make sure LEFT ingesters have no tokens
for n, ing := range inputRing.Ingesters {
if ing.State == LEFT {
ing.Tokens = nil
}
out[n] = ing
}
// Sort tokens, and remove duplicates
for name, ing := range out {
if len(ing.Tokens) == 0 {
continue
}
if !sort.IsSorted(Tokens(ing.Tokens)) {
sort.Sort(Tokens(ing.Tokens))
}
// tokens are sorted now, we can easily remove duplicates.
prev := ing.Tokens[0]
for ix := 1; ix < len(ing.Tokens); {
if ing.Tokens[ix] == prev {
ing.Tokens = append(ing.Tokens[:ix], ing.Tokens[ix+1:]...)
} else {
prev = ing.Tokens[ix]
ix++
}
}
// write updated value back to map
out[name] = ing
}
return out
}
func conflictingTokensExist(normalizedIngesters map[string]IngesterDesc) bool {
count := 0
for _, ing := range normalizedIngesters {
count += len(ing.Tokens)
}
tokensMap := make(map[uint32]bool, count)
for _, ing := range normalizedIngesters {
for _, t := range ing.Tokens {
if tokensMap[t] {
return true
}
tokensMap[t] = true
}
}
return false
}
// This function resolves token conflicts, if there are any.
//
// We deal with two possibilities:
// 1) if one node is LEAVING or LEFT and the other node is not, LEVING/LEFT one loses the token
// 2) otherwise node names are compared, and node with "lower" name wins the token
//
// Modifies ingesters map with updated tokens.
func resolveConflicts(normalizedIngesters map[string]IngesterDesc) {
size := 0
for _, ing := range normalizedIngesters {
size += len(ing.Tokens)
}
tokens := make([]uint32, 0, size)
tokenToIngester := make(map[uint32]string, size)
for ingKey, ing := range normalizedIngesters {
if ing.State == LEFT {
// LEFT ingesters don't use tokens anymore
continue
}
for _, token := range ing.Tokens {
prevKey, found := tokenToIngester[token]
if !found {
tokens = append(tokens, token)
tokenToIngester[token] = ingKey
} else {
// there is already ingester for this token, let's do conflict resolution
prevIng := normalizedIngesters[prevKey]
winnerKey := ingKey
switch {
case ing.State == LEAVING && prevIng.State != LEAVING:
winnerKey = prevKey
case prevIng.State == LEAVING && ing.State != LEAVING:
winnerKey = ingKey
case ingKey < prevKey:
winnerKey = ingKey
case prevKey < ingKey:
winnerKey = prevKey
}
tokenToIngester[token] = winnerKey
}
}
}
sort.Sort(Tokens(tokens))
// let's store the resolved result back
newTokenLists := map[string][]uint32{}
for key := range normalizedIngesters {
// make sure that all ingesters start with empty list
// especially ones that will no longer have any tokens
newTokenLists[key] = nil
}
// build list of tokens for each ingester
for _, token := range tokens {
key := tokenToIngester[token]
newTokenLists[key] = append(newTokenLists[key], token)
}
// write tokens back
for key, tokens := range newTokenLists {
ing := normalizedIngesters[key]
ing.Tokens = tokens
normalizedIngesters[key] = ing
}
}
// RemoveTombstones removes LEFT ingesters older than given time limit. If time limit is zero, remove all LEFT ingesters.
func (d *Desc) RemoveTombstones(limit time.Time) {
removed := 0
for n, ing := range d.Ingesters {
if ing.State == LEFT && (limit.IsZero() || time.Unix(ing.Timestamp, 0).Before(limit)) {
// remove it
delete(d.Ingesters, n)
removed++
}
}
}
func (d *Desc) getTokensInfo() map[uint32]instanceInfo {
out := map[uint32]instanceInfo{}
for instanceID, instance := range d.Ingesters {
info := instanceInfo{
InstanceID: instanceID,
Zone: instance.Zone,
}
for _, token := range instance.Tokens {
out[token] = info
}
}
return out
}
// GetTokens returns sorted list of tokens owned by all instances within the ring.
func (d *Desc) GetTokens() []uint32 {
instances := make([][]uint32, 0, len(d.Ingesters))
for _, instance := range d.Ingesters {
// Tokens may not be sorted for an older version of Cortex which, so we enforce sorting here.
tokens := instance.Tokens
if !sort.IsSorted(Tokens(tokens)) {
sort.Sort(Tokens(tokens))
}
instances = append(instances, tokens)
}
return MergeTokens(instances)
}
// getTokensByZone returns instances tokens grouped by zone. Tokens within each zone
// are guaranteed to be sorted.
func (d *Desc) getTokensByZone() map[string][]uint32 {
zones := map[string][][]uint32{}
for _, instance := range d.Ingesters {
// Tokens may not be sorted for an older version of Cortex which, so we enforce sorting here.
tokens := instance.Tokens
if !sort.IsSorted(Tokens(tokens)) {
sort.Sort(Tokens(tokens))
}
zones[instance.Zone] = append(zones[instance.Zone], tokens)
}
// Merge tokens per zone.
return MergeTokensByZone(zones)
}
type CompareResult int
const (
Equal CompareResult = iota // Both rings contain same exact instances.
EqualButStatesAndTimestamps // Both rings contain the same instances with the same data except states and timestamps (may differ).
Different // Rings have different set of instances, or their information don't match.
)
// RingCompare compares this ring against another one and returns one of Equal, EqualButStatesAndTimestamps or Different.
func (d *Desc) RingCompare(o *Desc) CompareResult {
if d == nil {
if o == nil || len(o.Ingesters) == 0 {
return Equal
}
return Different
}
if o == nil {
if len(d.Ingesters) == 0 {
return Equal
}
return Different
}
if len(d.Ingesters) != len(o.Ingesters) {
return Different
}
equalStatesAndTimestamps := true
for name, ing := range d.Ingesters {
oing, ok := o.Ingesters[name]
if !ok {
return Different
}
if ing.Addr != oing.Addr {
return Different
}
if ing.Zone != oing.Zone {
return Different
}
if ing.RegisteredTimestamp != oing.RegisteredTimestamp {
return Different
}
if len(ing.Tokens) != len(oing.Tokens) {
return Different
}
for ix, t := range ing.Tokens {
if oing.Tokens[ix] != t {
return Different
}
}
if ing.Timestamp != oing.Timestamp {
equalStatesAndTimestamps = false
}
if ing.State != oing.State {
equalStatesAndTimestamps = false
}
}
if equalStatesAndTimestamps {
return Equal
}
return EqualButStatesAndTimestamps
}
func GetOrCreateRingDesc(d interface{}) *Desc {
if d == nil {
return NewDesc()
}
return d.(*Desc)
}
// TokensHeap is an heap data structure used to merge multiple lists
// of sorted tokens into a single one.
type TokensHeap [][]uint32
func (h TokensHeap) Len() int {
return len(h)
}
func (h TokensHeap) Swap(i, j int) {
h[i], h[j] = h[j], h[i]
}
func (h TokensHeap) Less(i, j int) bool {
return h[i][0] < h[j][0]
}
func (h *TokensHeap) Push(x interface{}) {
*h = append(*h, x.([]uint32))
}
func (h *TokensHeap) Pop() interface{} {
old := *h
n := len(old)
x := old[n-1]
*h = old[0 : n-1]
return x
}
// MergeTokens takes in input multiple lists of tokens and returns a single list
// containing all tokens merged and sorted. Each input single list is required
// to have tokens already sorted.
func MergeTokens(instances [][]uint32) []uint32 {
numTokens := 0
// Build the heap.
h := make(TokensHeap, 0, len(instances))
for _, tokens := range instances {
if len(tokens) == 0 {
continue
}
// We can safely append the input slice because elements inside are never shuffled.
h = append(h, tokens)
numTokens += len(tokens)
}
heap.Init(&h)
out := make([]uint32, 0, numTokens)
for h.Len() > 0 {
// The minimum element in the tree is the root, at index 0.
lowest := h[0]
out = append(out, lowest[0])
if len(lowest) > 1 {
// Remove the first token from the lowest because we popped it
// and then fix the heap to keep it sorted.
h[0] = h[0][1:]
heap.Fix(&h, 0)
} else {
heap.Remove(&h, 0)
}
}
return out
}
// MergeTokensByZone is like MergeTokens but does it for each input zone.
func MergeTokensByZone(zones map[string][][]uint32) map[string][]uint32 {
out := make(map[string][]uint32, len(zones))
for zone, tokens := range zones {
out[zone] = MergeTokens(tokens)
}
return out
}