well-goknown/vendor/github.com/nbd-wtf/go-nostr/pool.go
2024-10-12 16:48:05 -04:00

491 lines
12 KiB
Go

package nostr
import (
"context"
"fmt"
"log"
"math"
"slices"
"strings"
"sync"
"time"
"github.com/puzpuzpuz/xsync/v3"
)
const (
seenAlreadyDropTick = time.Minute
)
type SimplePool struct {
Relays *xsync.MapOf[string, *Relay]
Context context.Context
authHandler func(context.Context, RelayEvent) error
cancel context.CancelFunc
eventMiddleware []func(RelayEvent)
// custom things not often used
penaltyBoxMu sync.Mutex
penaltyBox map[string][2]float64
userAgent string
}
type DirectedFilters struct {
Filters
Relay string
}
type RelayEvent struct {
*Event
Relay *Relay
}
func (ie RelayEvent) String() string {
return fmt.Sprintf("[%s] >> %s", ie.Relay.URL, ie.Event)
}
type PoolOption interface {
ApplyPoolOption(*SimplePool)
}
func NewSimplePool(ctx context.Context, opts ...PoolOption) *SimplePool {
ctx, cancel := context.WithCancel(ctx)
pool := &SimplePool{
Relays: xsync.NewMapOf[string, *Relay](),
Context: ctx,
cancel: cancel,
}
for _, opt := range opts {
opt.ApplyPoolOption(pool)
}
return pool
}
// WithAuthHandler must be a function that signs the auth event when called.
// it will be called whenever any relay in the pool returns a `CLOSED` message
// with the "auth-required:" prefix, only once for each relay
type WithAuthHandler func(ctx context.Context, authEvent RelayEvent) error
func (h WithAuthHandler) ApplyPoolOption(pool *SimplePool) {
pool.authHandler = h
}
// WithPenaltyBox just sets the penalty box mechanism so relays that fail to connect
// or that disconnect will be ignored for a while and we won't attempt to connect again.
func WithPenaltyBox() withPenaltyBoxOpt { return withPenaltyBoxOpt{} }
type withPenaltyBoxOpt struct{}
func (h withPenaltyBoxOpt) ApplyPoolOption(pool *SimplePool) {
pool.penaltyBox = make(map[string][2]float64)
go func() {
sleep := 30.0
for {
time.Sleep(time.Duration(sleep) * time.Second)
pool.penaltyBoxMu.Lock()
nextSleep := 300.0
for url, v := range pool.penaltyBox {
remainingSeconds := v[1]
remainingSeconds -= sleep
if remainingSeconds <= 0 {
pool.penaltyBox[url] = [2]float64{v[0], 0}
continue
} else {
pool.penaltyBox[url] = [2]float64{v[0], remainingSeconds}
}
if remainingSeconds < nextSleep {
nextSleep = remainingSeconds
}
}
sleep = nextSleep
pool.penaltyBoxMu.Unlock()
}
}()
}
// WithEventMiddleware is a function that will be called with all events received.
// more than one can be passed at a time.
type WithEventMiddleware func(RelayEvent)
func (h WithEventMiddleware) ApplyPoolOption(pool *SimplePool) {
pool.eventMiddleware = append(pool.eventMiddleware, h)
}
// WithUserAgent sets the user-agent header for all relay connections in the pool.
func WithUserAgent(userAgent string) withUserAgentOpt { return withUserAgentOpt(userAgent) }
type withUserAgentOpt string
func (h withUserAgentOpt) ApplyPoolOption(pool *SimplePool) {
pool.userAgent = string(h)
}
var (
_ PoolOption = (WithAuthHandler)(nil)
_ PoolOption = (WithEventMiddleware)(nil)
_ PoolOption = WithPenaltyBox()
_ PoolOption = WithUserAgent("")
)
func (pool *SimplePool) EnsureRelay(url string) (*Relay, error) {
nm := NormalizeURL(url)
defer namedLock(nm)()
relay, ok := pool.Relays.Load(nm)
if ok && relay == nil {
if pool.penaltyBox != nil {
pool.penaltyBoxMu.Lock()
defer pool.penaltyBoxMu.Unlock()
v, _ := pool.penaltyBox[nm]
if v[1] > 0 {
return nil, fmt.Errorf("in penalty box, %fs remaining", v[1])
}
}
} else if ok && relay.IsConnected() {
// already connected, unlock and return
return relay, nil
}
// try to connect
// we use this ctx here so when the pool dies everything dies
ctx, cancel := context.WithTimeout(pool.Context, time.Second*15)
defer cancel()
relay = NewRelay(context.Background(), url)
relay.RequestHeader.Set("User-Agent", pool.userAgent)
if err := relay.Connect(ctx); err != nil {
if pool.penaltyBox != nil {
// putting relay in penalty box
pool.penaltyBoxMu.Lock()
defer pool.penaltyBoxMu.Unlock()
v, _ := pool.penaltyBox[nm]
pool.penaltyBox[nm] = [2]float64{v[0] + 1, 30.0 + math.Pow(2, v[0]+1)}
}
return nil, fmt.Errorf("failed to connect: %w", err)
}
pool.Relays.Store(nm, relay)
return relay, nil
}
// SubMany opens a subscription with the given filters to multiple relays
// the subscriptions only end when the context is canceled
func (pool *SimplePool) SubMany(
ctx context.Context,
urls []string,
filters Filters,
opts ...SubscriptionOption,
) chan RelayEvent {
return pool.subMany(ctx, urls, filters, true, opts)
}
// SubManyNonUnique is like SubMany, but returns duplicate events if they come from different relays
func (pool *SimplePool) SubManyNonUnique(
ctx context.Context,
urls []string,
filters Filters,
opts ...SubscriptionOption,
) chan RelayEvent {
return pool.subMany(ctx, urls, filters, false, opts)
}
func (pool *SimplePool) subMany(
ctx context.Context,
urls []string,
filters Filters,
unique bool,
opts []SubscriptionOption,
) chan RelayEvent {
ctx, cancel := context.WithCancel(ctx)
_ = cancel // do this so `go vet` will stop complaining
events := make(chan RelayEvent)
seenAlready := xsync.NewMapOf[string, Timestamp]()
ticker := time.NewTicker(seenAlreadyDropTick)
eose := false
pending := xsync.NewCounter()
pending.Add(int64(len(urls)))
for i, url := range urls {
url = NormalizeURL(url)
urls[i] = url
if idx := slices.Index(urls, url); idx != i {
// skip duplicate relays in the list
continue
}
go func(nm string) {
defer func() {
pending.Dec()
if pending.Value() == 0 {
close(events)
}
cancel()
}()
hasAuthed := false
interval := 3 * time.Second
for {
select {
case <-ctx.Done():
return
default:
}
var sub *Subscription
relay, err := pool.EnsureRelay(nm)
if err != nil {
goto reconnect
}
hasAuthed = false
subscribe:
sub, err = relay.Subscribe(ctx, filters, opts...)
if err != nil {
goto reconnect
}
go func() {
<-sub.EndOfStoredEvents
eose = true
}()
// reset interval when we get a good subscription
interval = 3 * time.Second
for {
select {
case evt, more := <-sub.Events:
if !more {
// this means the connection was closed for weird reasons, like the server shut down
// so we will update the filters here to include only events seem from now on
// and try to reconnect until we succeed
now := Now()
for i := range filters {
filters[i].Since = &now
}
goto reconnect
}
ie := RelayEvent{Event: evt, Relay: relay}
for _, mh := range pool.eventMiddleware {
mh(ie)
}
if unique {
if _, seen := seenAlready.LoadOrStore(evt.ID, evt.CreatedAt); seen {
continue
}
}
select {
case events <- ie:
case <-ctx.Done():
return
}
case <-ticker.C:
if eose {
old := Timestamp(time.Now().Add(-seenAlreadyDropTick).Unix())
seenAlready.Range(func(id string, value Timestamp) bool {
if value < old {
seenAlready.Delete(id)
}
return true
})
}
case reason := <-sub.ClosedReason:
if strings.HasPrefix(reason, "auth-required:") && pool.authHandler != nil && !hasAuthed {
// relay is requesting auth. if we can we will perform auth and try again
err := relay.Auth(ctx, func(event *Event) error {
return pool.authHandler(ctx, RelayEvent{Event: event, Relay: relay})
})
if err == nil {
hasAuthed = true // so we don't keep doing AUTH again and again
goto subscribe
}
} else {
log.Printf("CLOSED from %s: '%s'\n", nm, reason)
}
return
case <-ctx.Done():
return
}
}
reconnect:
// we will go back to the beginning of the loop and try to connect again and again
// until the context is canceled
time.Sleep(interval)
interval = interval * 17 / 10 // the next time we try we will wait longer
}
}(url)
}
return events
}
// SubManyEose is like SubMany, but it stops subscriptions and closes the channel when gets a EOSE
func (pool *SimplePool) SubManyEose(
ctx context.Context,
urls []string,
filters Filters,
opts ...SubscriptionOption,
) chan RelayEvent {
return pool.subManyEose(ctx, urls, filters, true, opts)
}
// SubManyEoseNonUnique is like SubManyEose, but returns duplicate events if they come from different relays
func (pool *SimplePool) SubManyEoseNonUnique(
ctx context.Context,
urls []string,
filters Filters,
opts ...SubscriptionOption,
) chan RelayEvent {
return pool.subManyEose(ctx, urls, filters, false, opts)
}
func (pool *SimplePool) subManyEose(
ctx context.Context,
urls []string,
filters Filters,
unique bool,
opts []SubscriptionOption,
) chan RelayEvent {
ctx, cancel := context.WithCancel(ctx)
events := make(chan RelayEvent)
seenAlready := xsync.NewMapOf[string, bool]()
wg := sync.WaitGroup{}
wg.Add(len(urls))
go func() {
// this will happen when all subscriptions get an eose (or when they die)
wg.Wait()
cancel()
close(events)
}()
for _, url := range urls {
go func(nm string) {
defer wg.Done()
relay, err := pool.EnsureRelay(nm)
if err != nil {
return
}
hasAuthed := false
subscribe:
sub, err := relay.Subscribe(ctx, filters, opts...)
if sub == nil {
debugLogf("error subscribing to %s with %v: %s", relay, filters, err)
return
}
for {
select {
case <-ctx.Done():
return
case <-sub.EndOfStoredEvents:
return
case reason := <-sub.ClosedReason:
if strings.HasPrefix(reason, "auth-required:") && pool.authHandler != nil && !hasAuthed {
// relay is requesting auth. if we can we will perform auth and try again
err := relay.Auth(ctx, func(event *Event) error {
return pool.authHandler(ctx, RelayEvent{Event: event, Relay: relay})
})
if err == nil {
hasAuthed = true // so we don't keep doing AUTH again and again
goto subscribe
}
}
log.Printf("CLOSED from %s: '%s'\n", nm, reason)
return
case evt, more := <-sub.Events:
if !more {
return
}
ie := RelayEvent{Event: evt, Relay: relay}
for _, mh := range pool.eventMiddleware {
mh(ie)
}
if unique {
if _, seen := seenAlready.LoadOrStore(evt.ID, true); seen {
continue
}
}
select {
case events <- ie:
case <-ctx.Done():
return
}
}
}
}(NormalizeURL(url))
}
return events
}
// QuerySingle returns the first event returned by the first relay, cancels everything else.
func (pool *SimplePool) QuerySingle(ctx context.Context, urls []string, filter Filter) *RelayEvent {
ctx, cancel := context.WithCancel(ctx)
defer cancel()
for ievt := range pool.SubManyEose(ctx, urls, Filters{filter}) {
return &ievt
}
return nil
}
func (pool *SimplePool) batchedSubMany(
ctx context.Context,
dfs []DirectedFilters,
subFn func(context.Context, []string, Filters, bool, []SubscriptionOption) chan RelayEvent,
opts []SubscriptionOption,
) chan RelayEvent {
res := make(chan RelayEvent)
for _, df := range dfs {
go func(df DirectedFilters) {
for ie := range subFn(ctx, []string{df.Relay}, df.Filters, true, opts) {
res <- ie
}
}(df)
}
return res
}
// BatchedSubMany fires subscriptions only to specific relays, but batches them when they are the same.
func (pool *SimplePool) BatchedSubMany(
ctx context.Context,
dfs []DirectedFilters,
opts ...SubscriptionOption,
) chan RelayEvent {
return pool.batchedSubMany(ctx, dfs, pool.subMany, opts)
}
// BatchedSubManyEose is like BatchedSubMany, but ends upon receiving EOSE from all relays.
func (pool *SimplePool) BatchedSubManyEose(
ctx context.Context,
dfs []DirectedFilters,
opts ...SubscriptionOption,
) chan RelayEvent {
return pool.batchedSubMany(ctx, dfs, pool.subManyEose, opts)
}