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healthcheck.go
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healthcheck.go
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// Package discovery provides a way to discover all tablets e.g. within a
// specific shard and monitor their current health.
//
// Use the HealthCheck object to query for tablets and their health.
//
// For an example how to use the HealthCheck object, see worker/topo_utils.go.
//
// Tablets have to be manually added to the HealthCheck using AddTablet().
// Alternatively, use a Watcher implementation which will constantly watch
// a source (e.g. the topology) and add and remove tablets as they are
// added or removed from the source.
// For a Watcher example have a look at NewShardReplicationWatcher().
//
// Each HealthCheck has a HealthCheckStatsListener that will receive
// notification of when tablets go up and down.
// TabletStatsCache is one implementation, that caches the known tablets
// and the healthy ones per keyspace/shard/tabletType.
//
// Internally, the HealthCheck module is connected to each tablet and has a
// streaming RPC (StreamHealth) open to receive periodic health infos.
package discovery
import (
"fmt"
"html/template"
"sort"
"strings"
"sync"
"time"
log "github.com/golang/glog"
"github.com/golang/protobuf/proto"
"github.com/youtube/vitess/go/netutil"
"github.com/youtube/vitess/go/stats"
querypb "github.com/youtube/vitess/go/vt/proto/query"
topodatapb "github.com/youtube/vitess/go/vt/proto/topodata"
"github.com/youtube/vitess/go/vt/topo/topoproto"
"github.com/youtube/vitess/go/vt/vttablet/queryservice"
"github.com/youtube/vitess/go/vt/vttablet/tabletconn"
"golang.org/x/net/context"
)
var (
hcErrorCounters = stats.NewMultiCounters("HealthcheckErrors", []string{"Keyspace", "ShardName", "TabletType"})
hcMasterPromotedCounters = stats.NewMultiCounters("HealthcheckMasterPromoted", []string{"Keyspace", "ShardName"})
)
// See the documentation for NewHealthCheck below for an explanation of these parameters.
const (
DefaultHealthCheckConnTimeout = 1 * time.Minute
DefaultHealthCheckRetryDelay = 5 * time.Second
DefaultHealthCheckTimeout = 1 * time.Minute
)
const (
// DefaultTopoReadConcurrency can be used as default value for the topoReadConcurrency parameter of a TopologyWatcher.
DefaultTopoReadConcurrency int = 5
// DefaultTopologyWatcherRefreshInterval can be used as the default value for
// the refresh interval of a topology watcher.
DefaultTopologyWatcherRefreshInterval = 1 * time.Minute
// HealthCheckTemplate is the HTML code to display a TabletsCacheStatusList
HealthCheckTemplate = `
<style>
table {
border-collapse: collapse;
}
td, th {
border: 1px solid #999;
padding: 0.2rem;
}
</style>
<table>
<tr>
<th colspan="5">HealthCheck Tablet Cache</th>
</tr>
<tr>
<th>Cell</th>
<th>Keyspace</th>
<th>Shard</th>
<th>TabletType</th>
<th>TabletStats</th>
</tr>
{{range $i, $ts := .}}
<tr>
<td>{{github_com_youtube_vitess_vtctld_srv_cell $ts.Cell}}</td>
<td>{{github_com_youtube_vitess_vtctld_srv_keyspace $ts.Cell $ts.Target.Keyspace}}</td>
<td>{{$ts.Target.Shard}}</td>
<td>{{$ts.Target.TabletType}}</td>
<td>{{$ts.StatusAsHTML}}</td>
</tr>
{{end}}
</table>
`
)
// HealthCheckStatsListener is the listener to receive health check stats update.
type HealthCheckStatsListener interface {
// StatsUpdate is called when:
// - a new tablet is known to the HealthCheck, and its first
// streaming healthcheck is returned. (then ts.Up is true).
// - a tablet is removed from the list of tablets we watch
// (then ts.Up is false).
// - a tablet dynamically changes its type. When registering the
// listener, if sendDownEvents is true, two events are generated
// (ts.Up false on the old type, ts.Up true on the new type).
// If it is false, only one event is sent (ts.Up true on the new
// type).
StatsUpdate(*TabletStats)
}
// TabletStats is returned when getting the set of tablets.
type TabletStats struct {
// Key uniquely identifies that serving tablet. It is computed
// from the Tablet's record Hostname and PortMap. If a tablet
// is restarted on different ports, its Key will be different.
// Key is computed using the TabletToMapKey method below.
// key can be used in GetConnection().
Key string
// Tablet is the tablet object that was sent to HealthCheck.AddTablet.
Tablet *topodatapb.Tablet
// Name is an optional tag (e.g. alternative address) for the
// tablet. It is supposed to represent the tablet as a task,
// not as a process. For instance, it can be a
// cell+keyspace+shard+tabletType+taskIndex value.
Name string
// Target is the current target as returned by the streaming
// StreamHealth RPC.
Target *querypb.Target
// Up describes whether the tablet is added or removed.
Up bool
// Serving describes if the tablet can be serving traffic.
Serving bool
// TabletExternallyReparentedTimestamp is the last timestamp
// that this tablet was either elected the master, or received
// a TabletExternallyReparented event. It is set to 0 if the
// tablet doesn't think it's a master.
TabletExternallyReparentedTimestamp int64
// Stats is the current health status, as received by the
// StreamHealth RPC (replication lag, ...).
Stats *querypb.RealtimeStats
// LastError is the error we last saw when trying to get the
// tablet's healthcheck.
LastError error
}
// String is defined because we want to print a []*TabletStats array nicely.
func (e *TabletStats) String() string {
return fmt.Sprint(*e)
}
// DeepEqual compares two TabletStats. Since we include protos, we
// need to use proto.Equal on these.
func (e *TabletStats) DeepEqual(f *TabletStats) bool {
return e.Key == f.Key &&
proto.Equal(e.Tablet, f.Tablet) &&
e.Name == f.Name &&
proto.Equal(e.Target, f.Target) &&
e.Up == f.Up &&
e.Serving == f.Serving &&
e.TabletExternallyReparentedTimestamp == f.TabletExternallyReparentedTimestamp &&
proto.Equal(e.Stats, f.Stats) &&
((e.LastError == nil && f.LastError == nil) ||
(e.LastError != nil && f.LastError != nil && e.LastError.Error() == f.LastError.Error()))
}
// HealthCheck defines the interface of health checking module.
// The goal of this object is to maintain a StreamHealth RPC
// to a lot of tablets. Tablets are added / removed by calling the
// AddTablet / RemoveTablet methods (other discovery module objects
// can for instance watch the topology and call these).
//
// Updates to the health of all registered tablet can be watched by
// registering a listener. To get the underlying "TabletConn" object
// which is used for each tablet, use the "GetConnection()" method
// below and pass in the Key string which is also sent to the
// listener in each update (as it is part of TabletStats).
type HealthCheck interface {
// TabletRecorder interface adds AddTablet and RemoveTablet methods.
// AddTablet adds the tablet, and starts health check on it.
// RemoveTablet removes the tablet, and stops its StreamHealth RPC.
TabletRecorder
// RegisterStats registers the connection counts stats.
// It can only be called on one Healthcheck object per process.
RegisterStats()
// SetListener sets the listener for healthcheck
// updates. sendDownEvents is used when a tablet changes type
// (from replica to master for instance). If the listener
// wants two events (Up=false on old type, Up=True on new
// type), sendDownEvents should be set. Otherwise, the
// healthcheck will only send one event (Up=true on new type).
//
// Note that the default implementation requires to set the
// listener before any tablets are added to the healthcheck.
SetListener(listener HealthCheckStatsListener, sendDownEvents bool)
// WaitForInitialStatsUpdates waits until all tablets added via
// AddTablet() call were propagated to the listener via corresponding
// StatsUpdate() calls. Note that code path from AddTablet() to
// corresponding StatsUpdate() is asynchronous but not cancelable, thus
// this function is also non-cancelable and can't return error. Also
// note that all AddTablet() calls should happen before calling this
// method. WaitForInitialStatsUpdates won't wait for StatsUpdate() calls
// corresponding to AddTablet() calls made during its execution.
WaitForInitialStatsUpdates()
// GetConnection returns the TabletConn of the given tablet.
GetConnection(key string) queryservice.QueryService
// CacheStatus returns a displayable version of the cache.
CacheStatus() TabletsCacheStatusList
// Close stops the healthcheck.
Close() error
}
// healthCheckConn contains details about a tablet.
// It is used internally by HealthCheckImpl to keep all the info
// about a tablet.
type healthCheckConn struct {
// set at construction time
ctx context.Context
cancelFunc context.CancelFunc
// mu protects all the following fields.
// When locking both mutex from HealthCheck and healthCheckConn,
// HealthCheck.mu goes first.
// Note tabletStats.Tablet and tabletStats.Name are immutable.
mu sync.RWMutex
conn queryservice.QueryService
tabletStats TabletStats
lastResponseTimestamp time.Time // timestamp of the last healthcheck response
}
// HealthCheckImpl performs health checking and notifies downstream components about any changes.
type HealthCheckImpl struct {
// Immutable fields set at construction time.
listener HealthCheckStatsListener
sendDownEvents bool
connTimeout time.Duration
retryDelay time.Duration
healthCheckTimeout time.Duration
closeChan chan struct{} // signals the process gorouting to terminate
// wg keeps track of all launched Go routines.
wg sync.WaitGroup
// mu protects all the following fields.
// When locking both mutex from HealthCheck and healthCheckConn,
// HealthCheck.mu goes first.
mu sync.RWMutex
// addrToConns maps from address to the healthCheckConn object.
addrToConns map[string]*healthCheckConn
// Wait group that's used to wait until all initial StatsUpdate() calls are made after the AddTablet() calls.
initialUpdatesWG sync.WaitGroup
}
// NewDefaultHealthCheck creates a new HealthCheck object with a default configuration.
func NewDefaultHealthCheck() HealthCheck {
return NewHealthCheck(
DefaultHealthCheckConnTimeout, DefaultHealthCheckRetryDelay, DefaultHealthCheckTimeout)
}
// NewHealthCheck creates a new HealthCheck object.
// Parameters:
// connTimeout.
// The duration to wait until a health-check streaming connection is up.
// 0 means it should establish the connection in the background and return immediately.
// retryDelay.
// The duration to wait before retrying to connect (e.g. after a failed connection
// attempt).
// healthCheckTimeout.
// The duration for which we consider a health check response to be 'fresh'. If we don't get
// a health check response from a tablet for more than this duration, we consider the tablet
// not healthy.
func NewHealthCheck(connTimeout, retryDelay, healthCheckTimeout time.Duration) HealthCheck {
hc := &HealthCheckImpl{
addrToConns: make(map[string]*healthCheckConn),
connTimeout: connTimeout,
retryDelay: retryDelay,
healthCheckTimeout: healthCheckTimeout,
closeChan: make(chan struct{}),
}
hc.wg.Add(1)
go func() {
defer hc.wg.Done()
// Start another go routine to check timeout.
// Currently vttablet sends healthcheck response every 20 seconds.
// We set the default timeout to 1 minute (20s * 3),
// and also perform the timeout check in sync with vttablet frequency.
// When we change the healthcheck frequency on vttablet,
// we should also adjust here.
t := time.NewTicker(healthCheckTimeout / 3)
defer t.Stop()
for {
select {
case <-hc.closeChan:
return
case _, ok := <-t.C:
if !ok {
// the ticker stoped
return
}
hc.checkHealthCheckTimeout()
}
}
}()
return hc
}
// RegisterStats registers the connection counts stats
func (hc *HealthCheckImpl) RegisterStats() {
stats.NewMultiCountersFunc("HealthcheckConnections", []string{"Keyspace", "ShardName", "TabletType"}, hc.servingConnStats)
}
// servingConnStats returns the number of serving tablets per keyspace/shard/tablet type.
func (hc *HealthCheckImpl) servingConnStats() map[string]int64 {
res := make(map[string]int64)
hc.mu.RLock()
defer hc.mu.RUnlock()
for _, hcc := range hc.addrToConns {
hcc.mu.RLock()
if !hcc.tabletStats.Up || !hcc.tabletStats.Serving || hcc.tabletStats.LastError != nil {
hcc.mu.RUnlock()
continue
}
key := fmt.Sprintf("%s.%s.%s", hcc.tabletStats.Target.Keyspace, hcc.tabletStats.Target.Shard, topoproto.TabletTypeLString(hcc.tabletStats.Target.TabletType))
hcc.mu.RUnlock()
res[key]++
}
return res
}
// finalizeConn closes the health checking connection and sends the final
// notification about the tablet to downstream. To be called only on exit from
// checkConn().
func (hc *HealthCheckImpl) finalizeConn(hcc *healthCheckConn) {
hcc.mu.Lock()
if hcc.conn != nil {
hcc.conn.Close(hcc.ctx)
hcc.conn = nil
}
hcc.tabletStats.Up = false
hcc.tabletStats.Serving = false
// Note: checkConn() exits only when hcc.ctx.Done() is closed. Thus it's
// safe to simply get Err() value here and assign to LastError.
hcc.tabletStats.LastError = hcc.ctx.Err()
ts := hcc.tabletStats
hcc.mu.Unlock()
if hc.listener != nil {
hc.listener.StatsUpdate(&ts)
}
}
// checkConn performs health checking on the given tablet.
func (hc *HealthCheckImpl) checkConn(hcc *healthCheckConn, name string) {
defer hc.wg.Done()
defer hc.finalizeConn(hcc)
// Initial notification for downstream about the tablet existence.
hcc.mu.Lock()
ts := hcc.tabletStats
hcc.mu.Unlock()
if hc.listener != nil {
hc.listener.StatsUpdate(&ts)
}
hc.initialUpdatesWG.Done()
// Read stream health responses.
for {
hcc.stream(hc, func(shr *querypb.StreamHealthResponse) error {
return hcc.processResponse(hc, shr)
})
// Streaming RPC failed e.g. because vttablet was restarted.
// Sleep until the next retry is up or the context is done/canceled.
select {
case <-hcc.ctx.Done():
return
case <-time.After(hc.retryDelay):
}
}
}
// stream streams healthcheck responses to callback.
func (hcc *healthCheckConn) stream(hc *HealthCheckImpl, callback func(*querypb.StreamHealthResponse) error) {
hcc.mu.Lock()
conn := hcc.conn
hcc.mu.Unlock()
if conn == nil {
var err error
conn, err = tabletconn.GetDialer()(hcc.tabletStats.Tablet, hc.connTimeout)
if err != nil {
hcc.mu.Lock()
hcc.tabletStats.LastError = err
hcc.mu.Unlock()
return
}
hcc.mu.Lock()
hcc.conn = conn
hcc.tabletStats.LastError = nil
hcc.mu.Unlock()
}
if err := conn.StreamHealth(hcc.ctx, callback); err != nil {
hcc.mu.Lock()
hcc.conn.Close(hcc.ctx)
hcc.conn = nil
hcc.tabletStats.Target = &querypb.Target{}
hcc.tabletStats.Serving = false
hcc.tabletStats.LastError = err
hcc.mu.Unlock()
return
}
return
}
// processResponse reads one health check response, and notifies HealthCheckStatsListener.
func (hcc *healthCheckConn) processResponse(hc *HealthCheckImpl, shr *querypb.StreamHealthResponse) error {
select {
case <-hcc.ctx.Done():
return hcc.ctx.Err()
default:
}
// Check for invalid data, better than panicking.
if shr.Target == nil || shr.RealtimeStats == nil {
return fmt.Errorf("health stats is not valid: %v", shr)
}
// an app-level error from tablet, force serving state.
var healthErr error
serving := shr.Serving
if shr.RealtimeStats.HealthError != "" {
healthErr = fmt.Errorf("vttablet error: %v", shr.RealtimeStats.HealthError)
serving = false
}
// In the case where a tablet changes type (but not for the
// initial message), we want to log it, and maybe advertise it too.
if hcc.tabletStats.Target.TabletType != topodatapb.TabletType_UNKNOWN && hcc.tabletStats.Target.TabletType != shr.Target.TabletType {
// The Tablet type changed for the tablet. Get old value.
hcc.mu.RLock()
oldTs := hcc.tabletStats
hcc.mu.RUnlock()
// Log and maybe notify
log.Infof("HealthCheckUpdate(Type Change): %v, tablet: %v/%+v, target %+v => %+v, reparent time: %v", oldTs.Name, oldTs.Tablet.Alias.Cell, oldTs.Tablet, oldTs.Target, shr.Target, shr.TabletExternallyReparentedTimestamp)
if hc.listener != nil && hc.sendDownEvents {
oldTs.Up = false
hc.listener.StatsUpdate(&oldTs)
}
// Track how often a tablet gets promoted to master. It is used for
// comparing against the variables in go/vtgate/buffer/variables.go.
if oldTs.Target.TabletType != topodatapb.TabletType_MASTER && shr.Target.TabletType == topodatapb.TabletType_MASTER {
hcMasterPromotedCounters.Add([]string{shr.Target.Keyspace, shr.Target.Shard}, 1)
}
}
// Update our record, and notify downstream for tabletType and
// realtimeStats change.
ts := hcc.update(shr, serving, healthErr)
if hc.listener != nil {
hc.listener.StatsUpdate(&ts)
}
return nil
}
// update updates the stats of a healthCheckConn, and returns a copy
// of its tabletStats.
func (hcc *healthCheckConn) update(shr *querypb.StreamHealthResponse, serving bool, healthErr error) TabletStats {
hcc.mu.Lock()
defer hcc.mu.Unlock()
hcc.lastResponseTimestamp = time.Now()
hcc.tabletStats.Target = shr.Target
hcc.tabletStats.Serving = serving
hcc.tabletStats.TabletExternallyReparentedTimestamp = shr.TabletExternallyReparentedTimestamp
hcc.tabletStats.Stats = shr.RealtimeStats
hcc.tabletStats.LastError = healthErr
return hcc.tabletStats
}
func (hc *HealthCheckImpl) checkHealthCheckTimeout() {
hc.mu.RLock()
list := make([]*healthCheckConn, 0, len(hc.addrToConns))
for _, hcc := range hc.addrToConns {
list = append(list, hcc)
}
hc.mu.RUnlock()
for _, hcc := range list {
hcc.mu.RLock()
if !hcc.tabletStats.Serving {
// ignore non-serving tablet
hcc.mu.RUnlock()
continue
}
if time.Now().Sub(hcc.lastResponseTimestamp) < hc.healthCheckTimeout {
// received a healthcheck response recently
hcc.mu.RUnlock()
continue
}
hcc.mu.RUnlock()
// mark the tablet non-serving as we have not seen a health check response for a long time
hcc.mu.Lock()
// check again to avoid race condition
if !hcc.tabletStats.Serving {
// ignore non-serving tablet
hcc.mu.Unlock()
continue
}
if time.Now().Sub(hcc.lastResponseTimestamp) < hc.healthCheckTimeout {
// received a healthcheck response recently
hcc.mu.Unlock()
continue
}
hcc.tabletStats.Serving = false
hcc.tabletStats.LastError = fmt.Errorf("healthcheck timed out (latest %v)", hcc.lastResponseTimestamp)
ts := hcc.tabletStats
hcc.mu.Unlock()
// notify downstream for serving status change
if hc.listener != nil {
hc.listener.StatsUpdate(&ts)
}
hcErrorCounters.Add([]string{ts.Target.Keyspace, ts.Target.Shard, topoproto.TabletTypeLString(ts.Target.TabletType)}, 1)
}
}
func (hc *HealthCheckImpl) deleteConn(tablet *topodatapb.Tablet) {
hc.mu.Lock()
defer hc.mu.Unlock()
key := TabletToMapKey(tablet)
hcc, ok := hc.addrToConns[key]
if !ok {
log.Warningf("deleting unknown tablet: %+v", tablet)
return
}
hcc.mu.Lock()
hcc.tabletStats.Up = false
hcc.mu.Unlock()
hcc.cancelFunc()
delete(hc.addrToConns, key)
}
// SetListener sets the listener for healthcheck updates.
// It must be called after NewHealthCheck and before any tablets are added
// (either through AddTablet or through a Watcher).
func (hc *HealthCheckImpl) SetListener(listener HealthCheckStatsListener, sendDownEvents bool) {
if hc.listener != nil {
panic("must not call SetListener twice")
}
hc.mu.Lock()
defer hc.mu.Unlock()
if len(hc.addrToConns) > 0 {
panic("must not call SetListener after tablets were added")
}
hc.listener = listener
hc.sendDownEvents = sendDownEvents
}
// AddTablet adds the tablet, and starts health check.
// It does not block on making connection.
// name is an optional tag for the tablet, e.g. an alternative address.
func (hc *HealthCheckImpl) AddTablet(tablet *topodatapb.Tablet, name string) {
ctx, cancelFunc := context.WithCancel(context.Background())
key := TabletToMapKey(tablet)
hcc := &healthCheckConn{
ctx: ctx,
cancelFunc: cancelFunc,
tabletStats: TabletStats{
Key: key,
Tablet: tablet,
Name: name,
Target: &querypb.Target{},
Up: true,
},
}
hc.mu.Lock()
if _, ok := hc.addrToConns[key]; ok {
hc.mu.Unlock()
log.Warningf("adding duplicate tablet %v for %v: %+v", name, tablet.Alias.Cell, tablet)
return
}
hc.addrToConns[key] = hcc
hc.initialUpdatesWG.Add(1)
hc.mu.Unlock()
hc.wg.Add(1)
go hc.checkConn(hcc, name)
}
// RemoveTablet removes the tablet, and stops the health check.
// It does not block.
func (hc *HealthCheckImpl) RemoveTablet(tablet *topodatapb.Tablet) {
go hc.deleteConn(tablet)
}
// WaitForInitialStatsUpdates waits until all tablets added via AddTablet() call
// were propagated to downstream via corresponding StatsUpdate() calls.
func (hc *HealthCheckImpl) WaitForInitialStatsUpdates() {
hc.initialUpdatesWG.Wait()
}
// GetConnection returns the TabletConn of the given tablet.
func (hc *HealthCheckImpl) GetConnection(key string) queryservice.QueryService {
hc.mu.RLock()
defer hc.mu.RUnlock()
hcc := hc.addrToConns[key]
if hcc == nil {
return nil
}
hcc.mu.RLock()
defer hcc.mu.RUnlock()
return hcc.conn
}
// TabletsCacheStatus is the current tablets for a cell/target.
type TabletsCacheStatus struct {
Cell string
Target *querypb.Target
TabletsStats TabletStatsList
}
// TabletStatsList is used for sorting.
type TabletStatsList []*TabletStats
// Len is part of sort.Interface.
func (tsl TabletStatsList) Len() int {
return len(tsl)
}
// Less is part of sort.Interface
func (tsl TabletStatsList) Less(i, j int) bool {
name1 := tsl[i].Name
if name1 == "" {
name1 = tsl[i].Key
}
name2 := tsl[j].Name
if name2 == "" {
name2 = tsl[j].Key
}
return name1 < name2
}
// Swap is part of sort.Interface
func (tsl TabletStatsList) Swap(i, j int) {
tsl[i], tsl[j] = tsl[j], tsl[i]
}
// StatusAsHTML returns an HTML version of the status.
func (tcs *TabletsCacheStatus) StatusAsHTML() template.HTML {
tLinks := make([]string, 0, 1)
if tcs.TabletsStats != nil {
sort.Sort(tcs.TabletsStats)
}
for _, ts := range tcs.TabletsStats {
vtPort := ts.Tablet.PortMap["vt"]
color := "green"
extra := ""
if ts.LastError != nil {
color = "red"
extra = fmt.Sprintf(" (%v)", ts.LastError)
} else if !ts.Serving {
color = "red"
extra = " (Not Serving)"
} else if !ts.Up {
color = "red"
extra = " (Down)"
} else if ts.Target.TabletType == topodatapb.TabletType_MASTER {
extra = fmt.Sprintf(" (MasterTS: %v)", ts.TabletExternallyReparentedTimestamp)
} else {
extra = fmt.Sprintf(" (RepLag: %v)", ts.Stats.SecondsBehindMaster)
}
name := ts.Name
addr := netutil.JoinHostPort(ts.Tablet.Hostname, vtPort)
if name == "" {
name = addr
}
tLinks = append(tLinks, fmt.Sprintf(`<a href="http://%s" style="color:%v">%v</a>%v`, addr, color, name, extra))
}
return template.HTML(strings.Join(tLinks, "<br>"))
}
// TabletsCacheStatusList is used for sorting.
type TabletsCacheStatusList []*TabletsCacheStatus
// Len is part of sort.Interface.
func (tcsl TabletsCacheStatusList) Len() int {
return len(tcsl)
}
// Less is part of sort.Interface
func (tcsl TabletsCacheStatusList) Less(i, j int) bool {
return tcsl[i].Cell+"."+tcsl[i].Target.Keyspace+"."+tcsl[i].Target.Shard+"."+string(tcsl[i].Target.TabletType) <
tcsl[j].Cell+"."+tcsl[j].Target.Keyspace+"."+tcsl[j].Target.Shard+"."+string(tcsl[j].Target.TabletType)
}
// Swap is part of sort.Interface
func (tcsl TabletsCacheStatusList) Swap(i, j int) {
tcsl[i], tcsl[j] = tcsl[j], tcsl[i]
}
// CacheStatus returns a displayable version of the cache.
func (hc *HealthCheckImpl) CacheStatus() TabletsCacheStatusList {
tcsMap := make(map[string]*TabletsCacheStatus)
hc.mu.RLock()
for _, hcc := range hc.addrToConns {
hcc.mu.RLock()
key := fmt.Sprintf("%v.%v.%v.%v", hcc.tabletStats.Tablet.Alias.Cell, hcc.tabletStats.Target.Keyspace, hcc.tabletStats.Target.Shard, string(hcc.tabletStats.Target.TabletType))
var tcs *TabletsCacheStatus
var ok bool
if tcs, ok = tcsMap[key]; !ok {
tcs = &TabletsCacheStatus{
Cell: hcc.tabletStats.Tablet.Alias.Cell,
Target: hcc.tabletStats.Target,
}
tcsMap[key] = tcs
}
stats := hcc.tabletStats
hcc.mu.RUnlock()
tcs.TabletsStats = append(tcs.TabletsStats, &stats)
}
hc.mu.RUnlock()
tcsl := make(TabletsCacheStatusList, 0, len(tcsMap))
for _, tcs := range tcsMap {
tcsl = append(tcsl, tcs)
}
sort.Sort(tcsl)
return tcsl
}
// Close stops the healthcheck.
// After Close() returned, it's guaranteed that the listener isn't
// currently executing and won't be called again.
func (hc *HealthCheckImpl) Close() error {
hc.mu.Lock()
close(hc.closeChan)
for _, hcc := range hc.addrToConns {
hcc.cancelFunc()
}
hc.addrToConns = make(map[string]*healthCheckConn)
// Release the lock early or a pending checkHealthCheckTimeout
// cannot get a read lock on it.
hc.mu.Unlock()
// Wait for the checkHealthCheckTimeout Go routine and each Go
// routine per tablet.
hc.wg.Wait()
return nil
}
// TabletToMapKey creates a key to the map from tablet's host and ports.
// It should only be used in discovery and related module.
func TabletToMapKey(tablet *topodatapb.Tablet) string {
parts := make([]string, 0, 1)
for name, port := range tablet.PortMap {
parts = append(parts, netutil.JoinHostPort(name, port))
}
sort.Strings(parts)
parts = append([]string{tablet.Hostname}, parts...)
return strings.Join(parts, ",")
}