open-consul/agent/proxycfg/state.go

429 lines
14 KiB
Go

package proxycfg
import (
"context"
"errors"
"net"
"reflect"
"time"
"github.com/hashicorp/go-hclog"
"github.com/mitchellh/copystructure"
"github.com/hashicorp/consul/agent/cache"
cachetype "github.com/hashicorp/consul/agent/cache-types"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/consul/logging"
)
type CacheNotifier interface {
Notify(ctx context.Context, t string, r cache.Request,
correlationID string, ch chan<- cache.UpdateEvent) error
}
type Health interface {
Notify(ctx context.Context, req structs.ServiceSpecificRequest, correlationID string, ch chan<- cache.UpdateEvent) error
}
const (
coalesceTimeout = 200 * time.Millisecond
rootsWatchID = "roots"
leafWatchID = "leaf"
intentionsWatchID = "intentions"
serviceListWatchID = "service-list"
federationStateListGatewaysWatchID = "federation-state-list-mesh-gateways"
consulServerListWatchID = "consul-server-list"
datacentersWatchID = "datacenters"
serviceResolversWatchID = "service-resolvers"
gatewayServicesWatchID = "gateway-services"
gatewayConfigWatchID = "gateway-config"
externalServiceIDPrefix = "external-service:"
serviceLeafIDPrefix = "service-leaf:"
serviceConfigIDPrefix = "service-config:"
serviceResolverIDPrefix = "service-resolver:"
serviceIntentionsIDPrefix = "service-intentions:"
intentionUpstreamsID = "intention-upstreams"
meshConfigEntryID = "mesh"
svcChecksWatchIDPrefix = cachetype.ServiceHTTPChecksName + ":"
preparedQueryIDPrefix = string(structs.UpstreamDestTypePreparedQuery) + ":"
defaultPreparedQueryPollInterval = 30 * time.Second
)
type stateConfig struct {
logger hclog.Logger
source *structs.QuerySource
cache CacheNotifier
health Health
dnsConfig DNSConfig
serverSNIFn ServerSNIFunc
intentionDefaultAllow bool
}
// state holds all the state needed to maintain the config for a registered
// connect-proxy service. When a proxy registration is changed, the entire state
// is discarded and a new one created.
type state struct {
logger hclog.Logger
serviceInstance serviceInstance
handler kindHandler
// cancel is set by Watch and called by Close to stop the goroutine started
// in Watch.
cancel func()
ch chan cache.UpdateEvent
snapCh chan ConfigSnapshot
reqCh chan chan *ConfigSnapshot
}
type DNSConfig struct {
Domain string
AltDomain string
}
type ServerSNIFunc func(dc, nodeName string) string
type serviceInstance struct {
kind structs.ServiceKind
service string
proxyID structs.ServiceID
address string
port int
meta map[string]string
taggedAddresses map[string]structs.ServiceAddress
proxyCfg structs.ConnectProxyConfig
token string
}
func copyProxyConfig(ns *structs.NodeService) (structs.ConnectProxyConfig, error) {
if ns == nil {
return structs.ConnectProxyConfig{}, nil
}
// Copy the config map
proxyCfgRaw, err := copystructure.Copy(ns.Proxy)
if err != nil {
return structs.ConnectProxyConfig{}, err
}
proxyCfg, ok := proxyCfgRaw.(structs.ConnectProxyConfig)
if !ok {
return structs.ConnectProxyConfig{}, errors.New("failed to copy proxy config")
}
// we can safely modify these since we just copied them
for idx := range proxyCfg.Upstreams {
us := &proxyCfg.Upstreams[idx]
if us.DestinationType != structs.UpstreamDestTypePreparedQuery && us.DestinationNamespace == "" {
// default the upstreams target namespace to the namespace of the proxy
// doing this here prevents needing much more complex logic a bunch of other
// places and makes tracking these upstreams simpler as we can dedup them
// with the maps tracking upstream ids being watched.
proxyCfg.Upstreams[idx].DestinationNamespace = ns.EnterpriseMeta.NamespaceOrDefault()
}
}
return proxyCfg, nil
}
// newState populates the state struct by copying relevant fields from the
// NodeService and Token. We copy so that we can use them in a separate
// goroutine later without reasoning about races with the NodeService passed
// (especially for embedded fields like maps and slices).
//
// The returned state needs its required dependencies to be set before Watch
// can be called.
func newState(ns *structs.NodeService, token string, config stateConfig) (*state, error) {
// 10 is fairly arbitrary here but allow for the 3 mandatory and a
// reasonable number of upstream watches to all deliver their initial
// messages in parallel without blocking the cache.Notify loops. It's not a
// huge deal if we do for a short period so we don't need to be more
// conservative to handle larger numbers of upstreams correctly but gives
// some head room for normal operation to be non-blocking in most typical
// cases.
ch := make(chan cache.UpdateEvent, 10)
s, err := newServiceInstanceFromNodeService(ns, token)
if err != nil {
return nil, err
}
var handler kindHandler
h := handlerState{stateConfig: config, serviceInstance: s, ch: ch}
switch ns.Kind {
case structs.ServiceKindConnectProxy:
handler = &handlerConnectProxy{handlerState: h}
case structs.ServiceKindTerminatingGateway:
h.stateConfig.logger = config.logger.Named(logging.TerminatingGateway)
handler = &handlerTerminatingGateway{handlerState: h}
case structs.ServiceKindMeshGateway:
h.stateConfig.logger = config.logger.Named(logging.MeshGateway)
handler = &handlerMeshGateway{handlerState: h}
case structs.ServiceKindIngressGateway:
handler = &handlerIngressGateway{handlerState: h}
default:
return nil, errors.New("not a connect-proxy, terminating-gateway, mesh-gateway, or ingress-gateway")
}
return &state{
logger: config.logger.With("proxy", s.proxyID, "kind", s.kind),
serviceInstance: s,
handler: handler,
ch: ch,
snapCh: make(chan ConfigSnapshot, 1),
reqCh: make(chan chan *ConfigSnapshot, 1),
}, nil
}
func newServiceInstanceFromNodeService(ns *structs.NodeService, token string) (serviceInstance, error) {
proxyCfg, err := copyProxyConfig(ns)
if err != nil {
return serviceInstance{}, err
}
taggedAddresses := make(map[string]structs.ServiceAddress)
for k, v := range ns.TaggedAddresses {
taggedAddresses[k] = v
}
meta := make(map[string]string)
for k, v := range ns.Meta {
meta[k] = v
}
return serviceInstance{
kind: ns.Kind,
service: ns.Service,
proxyID: ns.CompoundServiceID(),
address: ns.Address,
port: ns.Port,
meta: meta,
taggedAddresses: taggedAddresses,
proxyCfg: proxyCfg,
token: token,
}, nil
}
type kindHandler interface {
initialize(ctx context.Context) (ConfigSnapshot, error)
handleUpdate(ctx context.Context, u cache.UpdateEvent, snap *ConfigSnapshot) error
}
// Watch initialized watches on all necessary cache data for the current proxy
// registration state and returns a chan to observe updates to the
// ConfigSnapshot that contains all necessary config state. The chan is closed
// when the state is Closed.
func (s *state) Watch() (<-chan ConfigSnapshot, error) {
var ctx context.Context
ctx, s.cancel = context.WithCancel(context.Background())
snap, err := s.handler.initialize(ctx)
if err != nil {
s.cancel()
return nil, err
}
go s.run(ctx, &snap)
return s.snapCh, nil
}
// Close discards the state and stops any long-running watches.
func (s *state) Close() error {
if s.cancel != nil {
s.cancel()
}
return nil
}
type handlerState struct {
stateConfig // TODO: un-embed
serviceInstance // TODO: un-embed
ch chan cache.UpdateEvent
}
func newConfigSnapshotFromServiceInstance(s serviceInstance, config stateConfig) ConfigSnapshot {
// TODO: use serviceInstance type in ConfigSnapshot
return ConfigSnapshot{
Kind: s.kind,
Service: s.service,
ProxyID: s.proxyID,
Address: s.address,
Port: s.port,
ServiceMeta: s.meta,
TaggedAddresses: s.taggedAddresses,
Proxy: s.proxyCfg,
Datacenter: config.source.Datacenter,
ServerSNIFn: config.serverSNIFn,
IntentionDefaultAllow: config.intentionDefaultAllow,
}
}
func (s *state) run(ctx context.Context, snap *ConfigSnapshot) {
// Close the channel we return from Watch when we stop so consumers can stop
// watching and clean up their goroutines. It's important we do this here and
// not in Close since this routine sends on this chan and so might panic if it
// gets closed from another goroutine.
defer close(s.snapCh)
// This turns out to be really fiddly/painful by just using time.Timer.C
// directly in the code below since you can't detect when a timer is stopped
// vs waiting in order to know to reset it. So just use a chan to send
// ourselves messages.
sendCh := make(chan struct{})
var coalesceTimer *time.Timer
for {
select {
case <-ctx.Done():
return
case u := <-s.ch:
s.logger.Trace("A blocking query returned; handling snapshot update", "correlationID", u.CorrelationID)
if err := s.handler.handleUpdate(ctx, u, snap); err != nil {
s.logger.Error("Failed to handle update from watch",
"id", u.CorrelationID, "error", err,
)
continue
}
case <-sendCh:
// Make a deep copy of snap so we don't mutate any of the embedded structs
// etc on future updates.
snapCopy, err := snap.Clone()
if err != nil {
s.logger.Error("Failed to copy config snapshot for proxy", "error", err)
continue
}
select {
// Try to send
case s.snapCh <- *snapCopy:
s.logger.Trace("Delivered new snapshot to proxy config watchers")
// Allow the next change to trigger a send
coalesceTimer = nil
// Skip rest of loop - there is nothing to send since nothing changed on
// this iteration
continue
// Avoid blocking if a snapshot is already buffered in snapCh as this can result in a deadlock.
// See PR #9689 for more details.
default:
s.logger.Trace("Failed to deliver new snapshot to proxy config watchers")
// Reset the timer to retry later. This is to ensure we attempt to redeliver the updated snapshot shortly.
if coalesceTimer == nil {
coalesceTimer = time.AfterFunc(coalesceTimeout, func() {
sendCh <- struct{}{}
})
}
// Do not reset coalesceTimer since we just queued a timer-based refresh
continue
}
case replyCh := <-s.reqCh:
s.logger.Trace("A proxy config snapshot was requested")
if !snap.Valid() {
// Not valid yet just respond with nil and move on to next task.
replyCh <- nil
s.logger.Trace("The proxy's config snapshot is not valid yet")
continue
}
// Make a deep copy of snap so we don't mutate any of the embedded structs
// etc on future updates.
snapCopy, err := snap.Clone()
if err != nil {
s.logger.Error("Failed to copy config snapshot for proxy", "error", err)
continue
}
replyCh <- snapCopy
// Skip rest of loop - there is nothing to send since nothing changed on
// this iteration
continue
}
// Check if snap is complete enough to be a valid config to deliver to a
// proxy yet.
if snap.Valid() {
// Don't send it right away, set a short timer that will wait for updates
// from any of the other cache values and deliver them all together.
if coalesceTimer == nil {
coalesceTimer = time.AfterFunc(coalesceTimeout, func() {
// This runs in another goroutine so we can't just do the send
// directly here as access to snap is racy. Instead, signal the main
// loop above.
sendCh <- struct{}{}
})
}
}
}
}
// CurrentSnapshot synchronously returns the current ConfigSnapshot if there is
// one ready. If we don't have one yet because not all necessary parts have been
// returned (i.e. both roots and leaf cert), nil is returned.
func (s *state) CurrentSnapshot() *ConfigSnapshot {
// Make a chan for the response to be sent on
ch := make(chan *ConfigSnapshot, 1)
s.reqCh <- ch
// Wait for the response
return <-ch
}
// Changed returns whether or not the passed NodeService has had any of the
// fields we care about for config state watching changed or a different token.
func (s *state) Changed(ns *structs.NodeService, token string) bool {
if ns == nil {
return true
}
proxyCfg, err := copyProxyConfig(ns)
if err != nil {
s.logger.Warn("Failed to parse proxy config and will treat the new service as unchanged")
}
i := s.serviceInstance
return ns.Kind != i.kind ||
i.proxyID != ns.CompoundServiceID() ||
i.address != ns.Address ||
i.port != ns.Port ||
!reflect.DeepEqual(i.proxyCfg, proxyCfg) ||
i.token != token
}
// hostnameEndpoints returns all CheckServiceNodes that have hostnames instead of IPs as the address.
// Envoy cannot resolve hostnames provided through EDS, so we exclusively use CDS for these clusters.
// If there is a mix of hostnames and addresses we exclusively use the hostnames, since clusters cannot discover
// services with both EDS and DNS.
func hostnameEndpoints(logger hclog.Logger, localDC string, nodes structs.CheckServiceNodes) structs.CheckServiceNodes {
var (
hasIP bool
hasHostname bool
resp structs.CheckServiceNodes
)
for _, n := range nodes {
addr, _ := n.BestAddress(localDC != n.Node.Datacenter)
if net.ParseIP(addr) != nil {
hasIP = true
continue
}
hasHostname = true
resp = append(resp, n)
}
if hasHostname && hasIP {
dc := nodes[0].Node.Datacenter
sn := nodes[0].Service.CompoundServiceName()
logger.Warn("service contains instances with mix of hostnames and IP addresses; only hostnames will be passed to Envoy",
"dc", dc, "service", sn.String())
}
return resp
}