14358372723

Committed 09 Apr 2025 01:26PM UTC coverage: 56.696% (-12.3%) from 69.037%

Build # 14358372723

Build Type

Pull #9696

github

Committed by

web-flow

Commit Message

Merge e2837e400 into 867d27d68

Pull Request Pull Request #9696: Add `development_guidelines.md` for both human and machine

Run Details

107055 of 188823 relevant lines covered (56.7%)

22721.56 hits per line

Source File
Press 'n' to go to next uncovered line, 'b' for previous

86.32

/subscribe/subscribe.go

package subscribe

import (
        "errors"
        "sync"
        "sync/atomic"

        "github.com/lightningnetwork/lnd/queue"
)

// ErrServerShuttingDown is an error returned in case the server is in the
// process of shutting down.
var ErrServerShuttingDown = errors.New("subscription server shutting down")

// Client is used to get notified about updates the caller has subscribed to,
type Client struct {
        // cancel should be called in case the client no longer wants to
        // subscribe for updates from the server.
        cancel func()

        updates *queue.ConcurrentQueue
        quit    chan struct{}
}

// Updates returns a read-only channel where the updates the client has
// subscribed to will be delivered.
func (c *Client) Updates() <-chan interface{} {
        return c.updates.ChanOut()
}

// Quit is a channel that will be closed in case the server decides to no
// longer deliver updates to this client.
func (c *Client) Quit() <-chan struct{} {
        return c.quit
}

// Cancel should be called in case the client no longer wants to
// subscribe for updates from the server.
func (c *Client) Cancel() {
        c.cancel()
}

// Server is a struct that manages a set of subscriptions and their
// corresponding clients. Any update will be delivered to all active clients.
type Server struct {
        clientCounter uint64 // To be used atomically.

        started uint32 // To be used atomically.
        stopped uint32 // To be used atomically.

        clients       map[uint64]*Client
        clientUpdates chan *clientUpdate

        updates chan interface{}

        quit chan struct{}
        wg   sync.WaitGroup
}

// clientUpdate is an internal message sent to the subscriptionHandler to
// either register a new client for subscription or cancel an existing
// subscription.
type clientUpdate struct {
        // cancel indicates if the update to the client is cancelling an
        // existing client's subscription. If not then this update will be to
        // subscribe a new client.
        cancel bool

        // clientID is the unique identifier for this client. Any further
        // updates (deleting or adding) to this notification client will be
        // dispatched according to the target clientID.
        clientID uint64

        // client is the new client that will receive updates. Will be nil in
        // case this is a cancellation update.
        client *Client
}

// NewServer returns a new Server.
func NewServer() *Server {
        return &Server{
                clients:       make(map[uint64]*Client),
                clientUpdates: make(chan *clientUpdate),
                updates:       make(chan interface{}),
                quit:          make(chan struct{}),
        }
}

// Start starts the Server, making it ready to accept subscriptions and
// updates.
func (s *Server) Start() error {
        if !atomic.CompareAndSwapUint32(&s.started, 0, 1) {
                return nil
        }

        s.wg.Add(1)
        go s.subscriptionHandler()

        return nil
}

// Stop stops the server.
func (s *Server) Stop() error {
        if !atomic.CompareAndSwapUint32(&s.stopped, 0, 1) {
                return nil
        }

        close(s.quit)
        s.wg.Wait()

        return nil
}

// Subscribe returns a Client that will receive updates any time the Server is
// made aware of a new event.
func (s *Server) Subscribe() (*Client, error) {
        // We'll first atomically obtain the next ID for this client from the
        // incrementing client ID counter.
        clientID := atomic.AddUint64(&s.clientCounter, 1)

        // Create the client that will be returned. The Cancel method is
        // populated to send the cancellation intent to the
        // subscriptionHandler.
        client := &Client{
                updates: queue.NewConcurrentQueue(20),
                quit:    make(chan struct{}),
                cancel: func() {
                        select {
                        case s.clientUpdates <- &clientUpdate{
                                cancel:   true,
                                clientID: clientID,
                        }:
                        case <-s.quit:
                                return
                        }
                },
        }

        select {
        case s.clientUpdates <- &clientUpdate{
                cancel:   false,
                clientID: clientID,
                client:   client,
        }:
        case <-s.quit:
                return nil, ErrServerShuttingDown
        }

        return client, nil
}

// SendUpdate is called to send the passed update to all currently active
// subscription clients.
func (s *Server) SendUpdate(update interface{}) error {

        select {
        case s.updates <- update:
                return nil
        case <-s.quit:
                return ErrServerShuttingDown
        }
}

// subscriptionHandler is the main handler for the Server. It will handle
// incoming updates and subscriptions, and forward the incoming updates to the
// registered clients.
//
// NOTE: MUST be run as a goroutine.
func (s *Server) subscriptionHandler() {
        defer s.wg.Done()

        for {
                select {

                // If a client update is received, the either a new
                // subscription becomes active, or we cancel and existing one.
                case update := <-s.clientUpdates:
                        clientID := update.clientID

                        // In case this is a cancellation, stop the client's
                        // underlying queue, and remove the client from the set
                        // of active subscription clients.
                        if update.cancel {
                                client, ok := s.clients[update.clientID]
                                if ok {
                                        client.updates.Stop()
                                        close(client.quit)
                                        delete(s.clients, clientID)
                                }

                                continue
                        }

                        // If this was not a cancellation, start the underlying
                        // queue and add the client to our set of subscription
                        // clients. It will be notified about any new updates
                        // the server receives.
                        update.client.updates.Start()
                        s.clients[update.clientID] = update.client

                // A new update was received, forward it to all active clients.
                case upd := <-s.updates:
                        for _, client := range s.clients {
                                select {
                                case client.updates.ChanIn() <- upd:
                                case <-client.quit:
                                case <-s.quit:
                                        return
                                }
                        }

                // In case the server is shutting down, stop the clients and
                // close the quit channels to notify them.
                case <-s.quit:
                        for _, client := range s.clients {
                                client.updates.Stop()
                                close(client.quit)
                        }
                        return
                }
        }
}

1	package subscribe
2
3	import (
4	"errors"
5	"sync"
6	"sync/atomic"
7
8	"github.com/lightningnetwork/lnd/queue"
9	)
10
11	// ErrServerShuttingDown is an error returned in case the server is in the
12	// process of shutting down.
13	var ErrServerShuttingDown = errors.New("subscription server shutting down")
14
15	// Client is used to get notified about updates the caller has subscribed to,
16	type Client struct {
17	// cancel should be called in case the client no longer wants to
18	// subscribe for updates from the server.
19	cancel func()
20
21	updates *queue.ConcurrentQueue
22	quit chan struct{}
23	}
24
25	// Updates returns a read-only channel where the updates the client has
26	// subscribed to will be delivered.
27	func (c *Client) Updates() <-chan interface{} {	150,009✔
28	return c.updates.ChanOut()	150,009✔
29	}	150,009✔
30
31	// Quit is a channel that will be closed in case the server decides to no
32	// longer deliver updates to this client.
33	func (c *Client) Quit() <-chan struct{} {	100✔
34	return c.quit	100✔
35	}	100✔
36
37	// Cancel should be called in case the client no longer wants to
38	// subscribe for updates from the server.
39	func (c *Client) Cancel() {	106✔
40	c.cancel()	106✔
41	}	106✔
42
43	// Server is a struct that manages a set of subscriptions and their
44	// corresponding clients. Any update will be delivered to all active clients.
45	type Server struct {
46	clientCounter uint64 // To be used atomically.
47
48	started uint32 // To be used atomically.
49	stopped uint32 // To be used atomically.
50
51	clients map[uint64]*Client
52	clientUpdates chan *clientUpdate
53
54	updates chan interface{}
55
56	quit chan struct{}
57	wg sync.WaitGroup
58	}
59
60	// clientUpdate is an internal message sent to the subscriptionHandler to
61	// either register a new client for subscription or cancel an existing
62	// subscription.
63	type clientUpdate struct {
64	// cancel indicates if the update to the client is cancelling an
65	// existing client's subscription. If not then this update will be to
66	// subscribe a new client.
67	cancel bool
68
69	// clientID is the unique identifier for this client. Any further
70	// updates (deleting or adding) to this notification client will be
71	// dispatched according to the target clientID.
72	clientID uint64
73
74	// client is the new client that will receive updates. Will be nil in
75	// case this is a cancellation update.
76	client *Client
77	}
78
79	// NewServer returns a new Server.
80	func NewServer() *Server {	26✔
81	return &Server{	26✔
82	clients: make(map[uint64]*Client),	26✔
83	clientUpdates: make(chan *clientUpdate),	26✔
84	updates: make(chan interface{}),	26✔
85	quit: make(chan struct{}),	26✔
86	}	26✔
87	}	26✔
88
89	// Start starts the Server, making it ready to accept subscriptions and
90	// updates.
91	func (s *Server) Start() error {	26✔
92	if !atomic.CompareAndSwapUint32(&s.started, 0, 1) {	26✔
93	return nil	×
94	}	×
95
96	s.wg.Add(1)	26✔
97	go s.subscriptionHandler()	26✔
98		26✔
99	return nil	26✔
100	}
101
102	// Stop stops the server.
103	func (s *Server) Stop() error {	25✔
104	if !atomic.CompareAndSwapUint32(&s.stopped, 0, 1) {	25✔
105	return nil	×
106	}	×
107
108	close(s.quit)	25✔
109	s.wg.Wait()	25✔
110		25✔
111	return nil	25✔
112	}
113
114	// Subscribe returns a Client that will receive updates any time the Server is
115	// made aware of a new event.
116	func (s Server) Subscribe() (Client, error) {	309✔
117	// We'll first atomically obtain the next ID for this client from the	309✔
118	// incrementing client ID counter.	309✔
119	clientID := atomic.AddUint64(&s.clientCounter, 1)	309✔
120		309✔
121	// Create the client that will be returned. The Cancel method is	309✔
122	// populated to send the cancellation intent to the	309✔
123	// subscriptionHandler.	309✔
124	client := &Client{	309✔
125	updates: queue.NewConcurrentQueue(20),	309✔
126	quit: make(chan struct{}),	309✔
127	cancel: func() {	415✔
128	select {	106✔
129	case s.clientUpdates <- &clientUpdate{
130	cancel: true,
131	clientID: clientID,
132	}:	106✔
133	case <-s.quit:	×
134	return	×
135	}
136	},
137	}
138
139	select {	309✔
140	case s.clientUpdates <- &clientUpdate{
141	cancel: false,
142	clientID: clientID,
143	client: client,
144	}:	309✔
145	case <-s.quit:	×
146	return nil, ErrServerShuttingDown	×
147	}
148
149	return client, nil	309✔
150	}
151
152	// SendUpdate is called to send the passed update to all currently active
153	// subscription clients.
154	func (s *Server) SendUpdate(update interface{}) error {	1,018✔
155		1,018✔
156	select {	1,018✔
157	case s.updates <- update:	1,018✔
158	return nil	1,018✔
159	case <-s.quit:	×
160	return ErrServerShuttingDown	×
161	}
162	}
163
164	// subscriptionHandler is the main handler for the Server. It will handle
165	// incoming updates and subscriptions, and forward the incoming updates to the
166	// registered clients.
167	//
168	// NOTE: MUST be run as a goroutine.
169	func (s *Server) subscriptionHandler() {	26✔
170	defer s.wg.Done()	26✔
171		26✔
172	for {	1,485✔
173	select {	1,459✔
174
175	// If a client update is received, the either a new
176	// subscription becomes active, or we cancel and existing one.
177	case update := <-s.clientUpdates:	415✔
178	clientID := update.clientID	415✔
179		415✔
180	// In case this is a cancellation, stop the client's	415✔
181	// underlying queue, and remove the client from the set	415✔
182	// of active subscription clients.	415✔
183	if update.cancel {	521✔
184	client, ok := s.clients[update.clientID]	106✔
185	if ok {	212✔
186	client.updates.Stop()	106✔
187	close(client.quit)	106✔
188	delete(s.clients, clientID)	106✔
189	}	106✔
190
191	continue	106✔
192	}
193
194	// If this was not a cancellation, start the underlying
195	// queue and add the client to our set of subscription
196	// clients. It will be notified about any new updates
197	// the server receives.
198	update.client.updates.Start()	309✔
199	s.clients[update.clientID] = update.client	309✔
200
201	// A new update was received, forward it to all active clients.
202	case upd := <-s.updates:	1,018✔
203	for _, client := range s.clients {	201,036✔
204	select {	200,018✔
205	case client.updates.ChanIn() <- upd:	200,018✔
206	case <-client.quit:	×
207	case <-s.quit:	×
208	return	×
209	}
210	}
211
212	// In case the server is shutting down, stop the clients and
213	// close the quit channels to notify them.
214	case <-s.quit:	25✔
215	for _, client := range s.clients {	28✔
216	client.updates.Stop()	3✔
217	close(client.quit)	3✔
218	}	3✔
219	return	25✔
220	}
221	}
222	}

lightningnetwork / lnd / 14358372723

Source File Press 'n' to go to next uncovered line, 'b' for previous

Source File
Press 'n' to go to next uncovered line, 'b' for previous