package proxycfg import ( "errors" "sync" "github.com/hashicorp/go-hclog" "github.com/hashicorp/consul/agent/structs" "github.com/hashicorp/consul/tlsutil" ) // ProxyID is a handle on a proxy service instance being tracked by Manager. type ProxyID struct { structs.ServiceID // NodeName identifies the node to which the proxy is registered. NodeName string // Token is used to track watches on the same proxy with different ACL tokens // separately, to prevent accidental security bugs. // // Note: this can be different to the ACL token used for authorization that is // passed to Register (e.g. agent-local services are registered ahead-of-time // with a token that may be different to the one presented in the xDS stream). Token string } // ProxySource identifies where a proxy service tracked by Manager came from, // such as the agent's local state or the catalog. It's used to prevent sources // from overwriting each other's registrations. type ProxySource string // CancelFunc is a type for a returned function that can be called to cancel a // watch. type CancelFunc func() // Manager provides an API with which proxy services can be registered, and // coordinates the fetching (and refreshing) of intentions, upstreams, discovery // chain, certificates etc. // // Consumers such as the xDS server can then subscribe to receive snapshots of // this data whenever it changes. // // See package docs for more detail. type Manager struct { ManagerConfig mu sync.Mutex proxies map[ProxyID]*state watchers map[ProxyID]map[uint64]chan *ConfigSnapshot maxWatchID uint64 } // ManagerConfig holds the required external dependencies for a Manager // instance. All fields must be set to something valid or the manager will // panic. The ManagerConfig is passed by value to NewManager so the passed value // can be mutated safely. type ManagerConfig struct { // DataSources contains the dependencies used to consume data used to configure // proxies. DataSources DataSources // source describes the current agent's identity, it's used directly for // prepared query discovery but also indirectly as a way to pass current // Datacenter name into other request types that need it. This is sufficient // for now and cleaner than passing the entire RuntimeConfig. Source *structs.QuerySource // DNSConfig is the agent's relevant DNS config for any proxies. DNSConfig DNSConfig // logger is the agent's logger to be used for logging logs. Logger hclog.Logger TLSConfigurator *tlsutil.Configurator // IntentionDefaultAllow is set by the agent so that we can pass this // information to proxies that need to make intention decisions on their // own. IntentionDefaultAllow bool } // NewManager constructs a Manager. func NewManager(cfg ManagerConfig) (*Manager, error) { if cfg.Source == nil || cfg.Logger == nil { return nil, errors.New("all ManagerConfig fields must be provided") } m := &Manager{ ManagerConfig: cfg, proxies: make(map[ProxyID]*state), watchers: make(map[ProxyID]map[uint64]chan *ConfigSnapshot), } return m, nil } // RegisteredProxies returns a list of the proxies tracked by Manager, filtered // by source. func (m *Manager) RegisteredProxies(source ProxySource) []ProxyID { m.mu.Lock() defer m.mu.Unlock() proxies := make([]ProxyID, 0, len(m.proxies)) for id, state := range m.proxies { if state.source != source { continue } proxies = append(proxies, id) } return proxies } // Register and start fetching resources for the given proxy service. If the // given service was already registered by a different source (e.g. we began // tracking it from the catalog, but then it was registered to the server // agent locally) the service will be left as-is unless overwrite is true. func (m *Manager) Register(id ProxyID, ns *structs.NodeService, source ProxySource, token string, overwrite bool) error { m.mu.Lock() defer m.mu.Unlock() state, ok := m.proxies[id] if ok { if state.source != source && !overwrite { // Registered by a different source, leave as-is. return nil } if !state.Changed(ns, token) { // No change return nil } // We are updating the proxy, close its old state state.Close() } // TODO: move to a function that translates ManagerConfig->stateConfig stateConfig := stateConfig{ logger: m.Logger.With("service_id", id.String()), dataSources: m.DataSources, source: m.Source, dnsConfig: m.DNSConfig, intentionDefaultAllow: m.IntentionDefaultAllow, } if m.TLSConfigurator != nil { stateConfig.serverSNIFn = m.TLSConfigurator.ServerSNI } var err error state, err = newState(id, ns, source, token, stateConfig) if err != nil { return err } ch, err := state.Watch() if err != nil { return err } m.proxies[id] = state // Start a goroutine that will wait for changes and broadcast them to watchers. go m.notifyBroadcast(ch) return nil } // Deregister the given proxy service, but only if it was registered by the same // source. func (m *Manager) Deregister(id ProxyID, source ProxySource) { m.mu.Lock() defer m.mu.Unlock() state, ok := m.proxies[id] if !ok { return } if state.source != source { return } // Closing state will let the goroutine we started in Register finish since // watch chan is closed. state.Close() delete(m.proxies, id) // We intentionally leave potential watchers hanging here - there is no new // config for them and closing their channels might be indistinguishable from // an error that they should retry. We rely for them to eventually give up // (because they are in fact not running any more) and so the watches be // cleaned up naturally. } func (m *Manager) notifyBroadcast(ch <-chan ConfigSnapshot) { // Run until ch is closed for snap := range ch { m.notify(&snap) } } func (m *Manager) notify(snap *ConfigSnapshot) { m.mu.Lock() defer m.mu.Unlock() watchers, ok := m.watchers[snap.ProxyID] if !ok { return } for _, ch := range watchers { m.deliverLatest(snap, ch) } } // deliverLatest delivers the snapshot to a watch chan. If the delivery blocks, // it will drain the chan and then re-attempt delivery so that a slow consumer // gets the latest config earlier. This MUST be called from a method where m.mu // is held to be safe since it assumes we are the only goroutine sending on ch. func (m *Manager) deliverLatest(snap *ConfigSnapshot, ch chan *ConfigSnapshot) { // Send if chan is empty select { case ch <- snap: return default: } // Not empty, drain the chan of older snapshots and redeliver. For now we only // use 1-buffered chans but this will still work if we change that later. OUTER: for { select { case <-ch: continue default: break OUTER } } // Now send again select { case ch <- snap: return default: // This should not be possible since we should be the only sender, enforced // by m.mu but error and drop the update rather than panic. m.Logger.Error("failed to deliver ConfigSnapshot to proxy", "proxy", snap.ProxyID.String(), ) } } // Watch registers a watch on a proxy. It might not exist yet in which case this // will not fail, but no updates will be delivered until the proxy is // registered. If there is already a valid snapshot in memory, it will be // delivered immediately. func (m *Manager) Watch(id ProxyID) (<-chan *ConfigSnapshot, CancelFunc) { m.mu.Lock() defer m.mu.Unlock() // This buffering is crucial otherwise we'd block immediately trying to // deliver the current snapshot below if we already have one. ch := make(chan *ConfigSnapshot, 1) watchers, ok := m.watchers[id] if !ok { watchers = make(map[uint64]chan *ConfigSnapshot) } watchID := m.maxWatchID m.maxWatchID++ watchers[watchID] = ch m.watchers[id] = watchers // Deliver the current snapshot immediately if there is one ready if state, ok := m.proxies[id]; ok { if snap := state.CurrentSnapshot(); snap != nil { // We rely on ch being buffered above and that it's not been passed // anywhere so we must be the only writer so this will never block and // deadlock. ch <- snap } } return ch, func() { m.mu.Lock() defer m.mu.Unlock() m.closeWatchLocked(id, watchID) } } // closeWatchLocked cleans up state related to a single watcher. It assumes the // lock is held. func (m *Manager) closeWatchLocked(proxyID ProxyID, watchID uint64) { if watchers, ok := m.watchers[proxyID]; ok { if ch, ok := watchers[watchID]; ok { delete(watchers, watchID) close(ch) if len(watchers) == 0 { delete(m.watchers, proxyID) } } } } // Close removes all state and stops all running goroutines. func (m *Manager) Close() error { m.mu.Lock() defer m.mu.Unlock() // Close all current watchers first for proxyID, watchers := range m.watchers { for watchID := range watchers { m.closeWatchLocked(proxyID, watchID) } } // Then close all states for proxyID, state := range m.proxies { state.Close() delete(m.proxies, proxyID) } return nil }