open-consul/command/agent/local.go

677 lines
19 KiB
Go

package agent
import (
"fmt"
"log"
"reflect"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/hashicorp/consul/consul"
"github.com/hashicorp/consul/consul/structs"
"github.com/hashicorp/consul/lib"
)
const (
syncStaggerIntv = 3 * time.Second
syncRetryIntv = 15 * time.Second
// permissionDenied is returned when an ACL based rejection happens
permissionDenied = "Permission denied"
)
// syncStatus is used to represent the difference between
// the local and remote state, and if action needs to be taken
type syncStatus struct {
remoteDelete bool // Should this be deleted from the server
inSync bool // Is this in sync with the server
}
// localState is used to represent the node's services,
// and checks. We used it to perform anti-entropy with the
// catalog representation
type localState struct {
// paused is used to check if we are paused. Must be the first
// element due to a go bug.
paused int32
sync.RWMutex
logger *log.Logger
// Config is the agent config
config *Config
// iface is the consul interface to use for keeping in sync
iface consul.Interface
// nodeInfoInSync tracks whether the server has our correct top-level
// node information in sync (currently only used for tagged addresses)
nodeInfoInSync bool
// Services tracks the local services
services map[string]*structs.NodeService
serviceStatus map[string]syncStatus
serviceTokens map[string]string
// Checks tracks the local checks
checks map[string]*structs.HealthCheck
checkStatus map[string]syncStatus
checkTokens map[string]string
// Used to track checks that are being deferred
deferCheck map[string]*time.Timer
// consulCh is used to inform of a change to the known
// consul nodes. This may be used to retry a sync run
consulCh chan struct{}
// triggerCh is used to inform of a change to local state
// that requires anti-entropy with the server
triggerCh chan struct{}
}
// Init is used to initialize the local state
func (l *localState) Init(config *Config, logger *log.Logger) {
l.config = config
l.logger = logger
l.services = make(map[string]*structs.NodeService)
l.serviceStatus = make(map[string]syncStatus)
l.serviceTokens = make(map[string]string)
l.checks = make(map[string]*structs.HealthCheck)
l.checkStatus = make(map[string]syncStatus)
l.checkTokens = make(map[string]string)
l.deferCheck = make(map[string]*time.Timer)
l.consulCh = make(chan struct{}, 1)
l.triggerCh = make(chan struct{}, 1)
}
// SetIface is used to set the Consul interface. Must be set prior to
// starting anti-entropy
func (l *localState) SetIface(iface consul.Interface) {
l.iface = iface
}
// changeMade is used to trigger an anti-entropy run
func (l *localState) changeMade() {
select {
case l.triggerCh <- struct{}{}:
default:
}
}
// ConsulServerUp is used to inform that a new consul server is now
// up. This can be used to speed up the sync process if we are blocking
// waiting to discover a consul server
func (l *localState) ConsulServerUp() {
select {
case l.consulCh <- struct{}{}:
default:
}
}
// Pause is used to pause state synchronization, this can be
// used to make batch changes
func (l *localState) Pause() {
atomic.AddInt32(&l.paused, 1)
}
// Resume is used to resume state synchronization
func (l *localState) Resume() {
paused := atomic.AddInt32(&l.paused, -1)
if paused < 0 {
panic("unbalanced localState.Resume() detected")
}
l.changeMade()
}
// isPaused is used to check if we are paused
func (l *localState) isPaused() bool {
return atomic.LoadInt32(&l.paused) > 0
}
// ServiceToken returns the configured ACL token for the given
// service ID. If none is present, the agent's token is returned.
func (l *localState) ServiceToken(id string) string {
l.RLock()
defer l.RUnlock()
return l.serviceToken(id)
}
// serviceToken returns an ACL token associated with a service.
func (l *localState) serviceToken(id string) string {
token := l.serviceTokens[id]
if token == "" {
token = l.config.ACLToken
}
return token
}
// AddService is used to add a service entry to the local state.
// This entry is persistent and the agent will make a best effort to
// ensure it is registered
func (l *localState) AddService(service *structs.NodeService, token string) {
// Assign the ID if none given
if service.ID == "" && service.Service != "" {
service.ID = service.Service
}
l.Lock()
defer l.Unlock()
l.services[service.ID] = service
l.serviceStatus[service.ID] = syncStatus{}
l.serviceTokens[service.ID] = token
l.changeMade()
}
// RemoveService is used to remove a service entry from the local state.
// The agent will make a best effort to ensure it is deregistered
func (l *localState) RemoveService(serviceID string) {
l.Lock()
defer l.Unlock()
delete(l.services, serviceID)
delete(l.serviceTokens, serviceID)
l.serviceStatus[serviceID] = syncStatus{remoteDelete: true}
l.changeMade()
}
// Services returns the locally registered services that the
// agent is aware of and are being kept in sync with the server
func (l *localState) Services() map[string]*structs.NodeService {
services := make(map[string]*structs.NodeService)
l.RLock()
defer l.RUnlock()
for name, serv := range l.services {
services[name] = serv
}
return services
}
// CheckToken is used to return the configured health check token, or
// if none is configured, the default agent ACL token.
func (l *localState) CheckToken(id string) string {
l.RLock()
defer l.RUnlock()
return l.checkToken(id)
}
// checkToken returns an ACL token associated with a check.
func (l *localState) checkToken(id string) string {
token := l.checkTokens[id]
if token == "" {
token = l.config.ACLToken
}
return token
}
// AddCheck is used to add a health check to the local state.
// This entry is persistent and the agent will make a best effort to
// ensure it is registered
func (l *localState) AddCheck(check *structs.HealthCheck, token string) {
// Set the node name
check.Node = l.config.NodeName
l.Lock()
defer l.Unlock()
l.checks[check.CheckID] = check
l.checkStatus[check.CheckID] = syncStatus{}
l.checkTokens[check.CheckID] = token
l.changeMade()
}
// RemoveCheck is used to remove a health check from the local state.
// The agent will make a best effort to ensure it is deregistered
func (l *localState) RemoveCheck(checkID string) {
l.Lock()
defer l.Unlock()
delete(l.checks, checkID)
delete(l.checkTokens, checkID)
l.checkStatus[checkID] = syncStatus{remoteDelete: true}
l.changeMade()
}
// UpdateCheck is used to update the status of a check
func (l *localState) UpdateCheck(checkID, status, output string) {
l.Lock()
defer l.Unlock()
check, ok := l.checks[checkID]
if !ok {
return
}
// Do nothing if update is idempotent
if check.Status == status && check.Output == output {
return
}
// Defer a sync if the output has changed. This is an optimization around
// frequent updates of output. Instead, we update the output internally,
// and periodically do a write-back to the servers. If there is a status
// change we do the write immediately.
if l.config.CheckUpdateInterval > 0 && check.Status == status {
check.Output = output
if _, ok := l.deferCheck[checkID]; !ok {
intv := time.Duration(uint64(l.config.CheckUpdateInterval)/2) + lib.RandomStagger(l.config.CheckUpdateInterval)
deferSync := time.AfterFunc(intv, func() {
l.Lock()
if _, ok := l.checkStatus[checkID]; ok {
l.checkStatus[checkID] = syncStatus{inSync: false}
l.changeMade()
}
delete(l.deferCheck, checkID)
l.Unlock()
})
l.deferCheck[checkID] = deferSync
}
return
}
// Update status and mark out of sync
check.Status = status
check.Output = output
l.checkStatus[checkID] = syncStatus{inSync: false}
l.changeMade()
}
// Checks returns the locally registered checks that the
// agent is aware of and are being kept in sync with the server
func (l *localState) Checks() map[string]*structs.HealthCheck {
checks := make(map[string]*structs.HealthCheck)
l.RLock()
defer l.RUnlock()
for name, check := range l.checks {
checks[name] = check
}
return checks
}
// antiEntropy is a long running method used to perform anti-entropy
// between local and remote state.
func (l *localState) antiEntropy(shutdownCh chan struct{}) {
SYNC:
// Sync our state with the servers
for {
err := l.setSyncState()
if err == nil {
break
}
l.logger.Printf("[ERR] agent: failed to sync remote state: %v", err)
select {
case <-l.consulCh:
// Stagger the retry on leader election, avoid a thundering heard
select {
case <-time.After(lib.RandomStagger(aeScale(syncStaggerIntv, len(l.iface.LANMembers())))):
case <-shutdownCh:
return
}
case <-time.After(syncRetryIntv + lib.RandomStagger(aeScale(syncRetryIntv, len(l.iface.LANMembers())))):
case <-shutdownCh:
return
}
}
// Force-trigger AE to pickup any changes
l.changeMade()
// Schedule the next full sync, with a random stagger
aeIntv := aeScale(l.config.AEInterval, len(l.iface.LANMembers()))
aeIntv = aeIntv + lib.RandomStagger(aeIntv)
aeTimer := time.After(aeIntv)
// Wait for sync events
for {
select {
case <-aeTimer:
goto SYNC
case <-l.triggerCh:
// Skip the sync if we are paused
if l.isPaused() {
continue
}
if err := l.syncChanges(); err != nil {
l.logger.Printf("[ERR] agent: failed to sync changes: %v", err)
}
case <-shutdownCh:
return
}
}
}
// setSyncState does a read of the server state, and updates
// the local syncStatus as appropriate
func (l *localState) setSyncState() error {
req := structs.NodeSpecificRequest{
Datacenter: l.config.Datacenter,
Node: l.config.NodeName,
QueryOptions: structs.QueryOptions{Token: l.config.ACLToken},
}
var out1 structs.IndexedNodeServices
var out2 structs.IndexedHealthChecks
if e := l.iface.RPC("Catalog.NodeServices", &req, &out1); e != nil {
return e
}
if err := l.iface.RPC("Health.NodeChecks", &req, &out2); err != nil {
return err
}
checks := out2.HealthChecks
l.Lock()
defer l.Unlock()
// Check the node info (currently limited to tagged addresses since
// everything else is managed by the Serf layer)
if out1.NodeServices == nil || out1.NodeServices.Node == nil ||
!reflect.DeepEqual(out1.NodeServices.Node.TaggedAddresses, l.config.TaggedAddresses) {
l.nodeInfoInSync = false
}
// Check all our services
services := make(map[string]*structs.NodeService)
if out1.NodeServices != nil {
services = out1.NodeServices.Services
}
for id, _ := range l.services {
// If the local service doesn't exist remotely, then sync it
if _, ok := services[id]; !ok {
l.serviceStatus[id] = syncStatus{inSync: false}
}
}
for id, service := range services {
// If we don't have the service locally, deregister it
existing, ok := l.services[id]
if !ok {
l.serviceStatus[id] = syncStatus{remoteDelete: true}
continue
}
// If our definition is different, we need to update it. Make a
// copy so that we don't retain a pointer to any actual state
// store info for in-memory RPCs.
if existing.EnableTagOverride {
existing.Tags = make([]string, len(service.Tags))
copy(existing.Tags, service.Tags)
}
equal := existing.IsSame(service)
l.serviceStatus[id] = syncStatus{inSync: equal}
}
// Index the remote health checks to improve efficiency
checkIndex := make(map[string]*structs.HealthCheck, len(checks))
for _, check := range checks {
checkIndex[check.CheckID] = check
}
// Sync any check which doesn't exist on the remote side
for id, _ := range l.checks {
if _, ok := checkIndex[id]; !ok {
l.checkStatus[id] = syncStatus{inSync: false}
}
}
for _, check := range checks {
// If we don't have the check locally, deregister it
id := check.CheckID
existing, ok := l.checks[id]
if !ok {
// The Serf check is created automatically, and does not
// need to be registered
if id == consul.SerfCheckID {
continue
}
l.checkStatus[id] = syncStatus{remoteDelete: true}
continue
}
// If our definition is different, we need to update it
var equal bool
if l.config.CheckUpdateInterval == 0 {
equal = existing.IsSame(check)
} else {
// Copy the existing check before potentially modifying
// it before the compare operation.
eCopy := existing.Clone()
// Copy the server's check before modifying, otherwise
// in-memory RPCs will have side effects.
cCopy := check.Clone()
// If there's a defer timer active then we've got a
// potentially spammy check so we don't sync the output
// during this sweep since the timer will mark the check
// out of sync for us. Otherwise, it is safe to sync the
// output now. This is especially important for checks
// that don't change state after they are created, in
// which case we'd never see their output synced back ever.
if _, ok := l.deferCheck[id]; ok {
eCopy.Output = ""
cCopy.Output = ""
}
equal = eCopy.IsSame(cCopy)
}
// Update the status
l.checkStatus[id] = syncStatus{inSync: equal}
}
return nil
}
// syncChanges is used to scan the status our local services and checks
// and update any that are out of sync with the server
func (l *localState) syncChanges() error {
l.Lock()
defer l.Unlock()
// We will do node-level info syncing at the end, since it will get
// updated by a service or check sync anyway, given how the register
// API works.
// Sync the services
for id, status := range l.serviceStatus {
if status.remoteDelete {
if err := l.deleteService(id); err != nil {
return err
}
} else if !status.inSync {
if err := l.syncService(id); err != nil {
return err
}
} else {
l.logger.Printf("[DEBUG] agent: Service '%s' in sync", id)
}
}
// Sync the checks
for id, status := range l.checkStatus {
if status.remoteDelete {
if err := l.deleteCheck(id); err != nil {
return err
}
} else if !status.inSync {
// Cancel a deferred sync
if timer := l.deferCheck[id]; timer != nil {
timer.Stop()
delete(l.deferCheck, id)
}
if err := l.syncCheck(id); err != nil {
return err
}
} else {
l.logger.Printf("[DEBUG] agent: Check '%s' in sync", id)
}
}
// Now sync the node level info if we need to, and didn't do any of
// the other sync operations.
if !l.nodeInfoInSync {
if err := l.syncNodeInfo(); err != nil {
return err
}
} else {
l.logger.Printf("[DEBUG] agent: Node info in sync")
}
return nil
}
// deleteService is used to delete a service from the server
func (l *localState) deleteService(id string) error {
if id == "" {
return fmt.Errorf("ServiceID missing")
}
req := structs.DeregisterRequest{
Datacenter: l.config.Datacenter,
Node: l.config.NodeName,
ServiceID: id,
WriteRequest: structs.WriteRequest{Token: l.serviceToken(id)},
}
var out struct{}
err := l.iface.RPC("Catalog.Deregister", &req, &out)
if err == nil {
delete(l.serviceStatus, id)
l.logger.Printf("[INFO] agent: Deregistered service '%s'", id)
}
return err
}
// deleteCheck is used to delete a service from the server
func (l *localState) deleteCheck(id string) error {
if id == "" {
return fmt.Errorf("CheckID missing")
}
req := structs.DeregisterRequest{
Datacenter: l.config.Datacenter,
Node: l.config.NodeName,
CheckID: id,
WriteRequest: structs.WriteRequest{Token: l.checkToken(id)},
}
var out struct{}
err := l.iface.RPC("Catalog.Deregister", &req, &out)
if err == nil {
delete(l.checkStatus, id)
l.logger.Printf("[INFO] agent: Deregistered check '%s'", id)
}
return err
}
// syncService is used to sync a service to the server
func (l *localState) syncService(id string) error {
req := structs.RegisterRequest{
Datacenter: l.config.Datacenter,
Node: l.config.NodeName,
Address: l.config.AdvertiseAddr,
TaggedAddresses: l.config.TaggedAddresses,
Service: l.services[id],
WriteRequest: structs.WriteRequest{Token: l.serviceToken(id)},
}
// If the service has associated checks that are out of sync,
// piggyback them on the service sync so they are part of the
// same transaction and are registered atomically.
var checks structs.HealthChecks
for _, check := range l.checks {
if check.ServiceID == id {
if stat, ok := l.checkStatus[check.CheckID]; !ok || !stat.inSync {
checks = append(checks, check)
}
}
}
// Backwards-compatibility for Consul < 0.5
if len(checks) == 1 {
req.Check = checks[0]
} else {
req.Checks = checks
}
var out struct{}
err := l.iface.RPC("Catalog.Register", &req, &out)
if err == nil {
l.serviceStatus[id] = syncStatus{inSync: true}
// Given how the register API works, this info is also updated
// every time we sync a service.
l.nodeInfoInSync = true
l.logger.Printf("[INFO] agent: Synced service '%s'", id)
for _, check := range checks {
l.checkStatus[check.CheckID] = syncStatus{inSync: true}
}
} else if strings.Contains(err.Error(), permissionDenied) {
l.serviceStatus[id] = syncStatus{inSync: true}
l.logger.Printf("[WARN] agent: Service '%s' registration blocked by ACLs", id)
for _, check := range checks {
l.checkStatus[check.CheckID] = syncStatus{inSync: true}
}
return nil
}
return err
}
// syncCheck is used to sync a check to the server
func (l *localState) syncCheck(id string) error {
// Pull in the associated service if any
check := l.checks[id]
var service *structs.NodeService
if check.ServiceID != "" {
if serv, ok := l.services[check.ServiceID]; ok {
service = serv
}
}
req := structs.RegisterRequest{
Datacenter: l.config.Datacenter,
Node: l.config.NodeName,
Address: l.config.AdvertiseAddr,
TaggedAddresses: l.config.TaggedAddresses,
Service: service,
Check: l.checks[id],
WriteRequest: structs.WriteRequest{Token: l.checkToken(id)},
}
var out struct{}
err := l.iface.RPC("Catalog.Register", &req, &out)
if err == nil {
l.checkStatus[id] = syncStatus{inSync: true}
// Given how the register API works, this info is also updated
// every time we sync a service.
l.nodeInfoInSync = true
l.logger.Printf("[INFO] agent: Synced check '%s'", id)
} else if strings.Contains(err.Error(), permissionDenied) {
l.checkStatus[id] = syncStatus{inSync: true}
l.logger.Printf("[WARN] agent: Check '%s' registration blocked by ACLs", id)
return nil
}
return err
}
func (l *localState) syncNodeInfo() error {
req := structs.RegisterRequest{
Datacenter: l.config.Datacenter,
Node: l.config.NodeName,
Address: l.config.AdvertiseAddr,
TaggedAddresses: l.config.TaggedAddresses,
WriteRequest: structs.WriteRequest{Token: l.config.ACLToken},
}
var out struct{}
err := l.iface.RPC("Catalog.Register", &req, &out)
if err == nil {
l.nodeInfoInSync = true
l.logger.Printf("[INFO] agent: Synced node info")
} else if strings.Contains(err.Error(), permissionDenied) {
l.nodeInfoInSync = true
l.logger.Printf("[WARN] agent: Node info update blocked by ACLs")
return nil
}
return err
}