15635919293

Committed 13 Jun 2025 01:37PM UTC coverage: 56.351% (-2.0%) from 58.333%

Build # 15635919293

Build Type

Pull #9903

github

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web-flow

Commit Message

Merge 174181006 into 35102e7c3

Pull Request Pull Request #9903: docs: add sphinx replay description

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86.1

/channeldb/forwarding_log.go

package channeldb

import (
        "bytes"
        "errors"
        "io"
        "sort"
        "time"

        "github.com/btcsuite/btcwallet/walletdb"
        "github.com/lightningnetwork/lnd/fn/v2"
        "github.com/lightningnetwork/lnd/kvdb"
        "github.com/lightningnetwork/lnd/lnwire"
)

var (
        // forwardingLogBucket is the bucket that we'll use to store the
        // forwarding log. The forwarding log contains a time series database
        // of the forwarding history of a lightning daemon. Each key within the
        // bucket is a timestamp (in nano seconds since the unix epoch), and
        // the value a slice of a forwarding event for that timestamp.
        forwardingLogBucket = []byte("circuit-fwd-log")
)

const (
        // forwardingEventSize is the size of a forwarding event. The breakdown
        // is as follows:
        //
        //  * 8 byte incoming chan ID || 8 byte outgoing chan ID || 8 byte value in
        //    || 8 byte value out || 8 byte incoming htlc id || 8 byte
        //    outgoing htlc id
        //
        // From the value in and value out, callers can easily compute the
        // total fee extract from a forwarding event.
        forwardingEventSize = 48

        // MaxResponseEvents is the max number of forwarding events that will
        // be returned by a single query response. This size was selected to
        // safely remain under gRPC's 4MiB message size response limit. As each
        // full forwarding event (including the timestamp) is 40 bytes, we can
        // safely return 50k entries in a single response.
        MaxResponseEvents = 50000
)

// ForwardingLog returns an instance of the ForwardingLog object backed by the
// target database instance.
func (d *DB) ForwardingLog() *ForwardingLog {
        return &ForwardingLog{
                db: d,
        }
}

// ForwardingLog is a time series database that logs the fulfillment of payment
// circuits by a lightning network daemon. The log contains a series of
// forwarding events which map a timestamp to a forwarding event. A forwarding
// event describes which channels were used to create+settle a circuit, and the
// amount involved. Subtracting the outgoing amount from the incoming amount
// reveals the fee charged for the forwarding service.
type ForwardingLog struct {
        db *DB
}

// ForwardingEvent is an event in the forwarding log's time series. Each
// forwarding event logs the creation and tear-down of a payment circuit. A
// circuit is created once an incoming HTLC has been fully forwarded, and
// destroyed once the payment has been settled.
type ForwardingEvent struct {
        // Timestamp is the settlement time of this payment circuit.
        Timestamp time.Time

        // IncomingChanID is the incoming channel ID of the payment circuit.
        IncomingChanID lnwire.ShortChannelID

        // OutgoingChanID is the outgoing channel ID of the payment circuit.
        OutgoingChanID lnwire.ShortChannelID

        // AmtIn is the amount of the incoming HTLC. Subtracting this from the
        // outgoing amount gives the total fees of this payment circuit.
        AmtIn lnwire.MilliSatoshi

        // AmtOut is the amount of the outgoing HTLC. Subtracting the incoming
        // amount from this gives the total fees for this payment circuit.
        AmtOut lnwire.MilliSatoshi

        // IncomingHtlcID is the ID of the incoming HTLC in the payment circuit.
        // If this is not set, the value will be nil. This field is added in
        // v0.20 and is made optional to make it backward compatible with
        // existing forwarding events created before it's introduction.
        IncomingHtlcID fn.Option[uint64]

        // OutgoingHtlcID is the ID of the outgoing HTLC in the payment circuit.
        // If this is not set, the value will be nil. This field is added in
        // v0.20 and is made optional to make it backward compatible with
        // existing forwarding events created before it's introduction.
        OutgoingHtlcID fn.Option[uint64]
}

// encodeForwardingEvent writes out the target forwarding event to the passed
// io.Writer, using the expected DB format. Note that the timestamp isn't
// serialized as this will be the key value within the bucket.
func encodeForwardingEvent(w io.Writer, f *ForwardingEvent) error {
        // We check for the HTLC IDs if they are set. If they are not,
        // from v0.20 upward, we return an error to make it clear they are
        // required.
        incomingID, err := f.IncomingHtlcID.UnwrapOrErr(
                errors.New("incoming HTLC ID must be set"),
        )
        if err != nil {
                return err
        }

        outgoingID, err := f.OutgoingHtlcID.UnwrapOrErr(
                errors.New("outgoing HTLC ID must be set"),
        )
        if err != nil {
                return err
        }

        return WriteElements(
                w, f.IncomingChanID, f.OutgoingChanID, f.AmtIn, f.AmtOut,
                incomingID, outgoingID,
        )
}

// decodeForwardingEvent attempts to decode the raw bytes of a serialized
// forwarding event into the target ForwardingEvent. Note that the timestamp
// won't be decoded, as the caller is expected to set this due to the bucket
// structure of the forwarding log.
func decodeForwardingEvent(r io.Reader, f *ForwardingEvent) error {
        // Decode the original fields of the forwarding event.
        err := ReadElements(
                r, &f.IncomingChanID, &f.OutgoingChanID, &f.AmtIn, &f.AmtOut,
        )
        if err != nil {
                return err
        }

        // Decode the incoming and outgoing htlc IDs. For backward compatibility
        // with older records that don't have these fields, we handle EOF by
        // setting the ID to nil. Any other error is treated as a read failure.
        var incomingHtlcID, outgoingHtlcID uint64
        err = ReadElements(r, &incomingHtlcID, &outgoingHtlcID)
        switch {
        case err == nil:
                f.IncomingHtlcID = fn.Some(incomingHtlcID)
                f.OutgoingHtlcID = fn.Some(outgoingHtlcID)

                return nil

        case errors.Is(err, io.EOF):
                return nil

        default:
                return err
        }
}

// AddForwardingEvents adds a series of forwarding events to the database.
// Before inserting, the set of events will be sorted according to their
// timestamp. This ensures that all writes to disk are sequential.
func (f *ForwardingLog) AddForwardingEvents(events []ForwardingEvent) error {
        // Before we create the database transaction, we'll ensure that the set
        // of forwarding events are properly sorted according to their
        // timestamp and that no duplicate timestamps exist to avoid collisions
        // in the key we are going to store the events under.
        makeUniqueTimestamps(events)

        var timestamp [8]byte

        return kvdb.Batch(f.db.Backend, func(tx kvdb.RwTx) error {
                // First, we'll fetch the bucket that stores our time series
                // log.
                logBucket, err := tx.CreateTopLevelBucket(
                        forwardingLogBucket,
                )
                if err != nil {
                        return err
                }

                // With the bucket obtained, we can now begin to write out the
                // series of events.
                for _, event := range events {
                        err := storeEvent(logBucket, event, timestamp[:])
                        if err != nil {
                                return err
                        }
                }

                return nil
        })
}

// storeEvent tries to store a forwarding event into the given bucket by trying
// to avoid collisions. If a key for the event timestamp already exists in the
// database, the timestamp is incremented in nanosecond intervals until a "free"
// slot is found.
func storeEvent(bucket walletdb.ReadWriteBucket, event ForwardingEvent,
        timestampScratchSpace []byte) error {

        // First, we'll serialize this timestamp into our
        // timestamp buffer.
        byteOrder.PutUint64(
                timestampScratchSpace, uint64(event.Timestamp.UnixNano()),
        )

        // Next we'll loop until we find a "free" slot in the bucket to store
        // the event under. This should almost never happen unless we're running
        // on a system that has a very bad system clock that doesn't properly
        // resolve to nanosecond scale. We try up to 100 times (which would come
        // to a maximum shift of 0.1 microsecond which is acceptable for most
        // use cases). If we don't find a free slot, we just give up and let
        // the collision happen. Something must be wrong with the data in that
        // case, even on a very fast machine forwarding payments _will_ take a
        // few microseconds at least so we should find a nanosecond slot
        // somewhere.
        const maxTries = 100
        tries := 0
        for tries < maxTries {
                val := bucket.Get(timestampScratchSpace)
                if val == nil {
                        break
                }

                // Collision, try the next nanosecond timestamp.
                nextNano := event.Timestamp.UnixNano() + 1
                event.Timestamp = time.Unix(0, nextNano)
                byteOrder.PutUint64(timestampScratchSpace, uint64(nextNano))
                tries++
        }

        // With the key encoded, we'll then encode the event
        // into our buffer, then write it out to disk.
        var eventBytes [forwardingEventSize]byte
        eventBuf := bytes.NewBuffer(eventBytes[0:0:forwardingEventSize])
        err := encodeForwardingEvent(eventBuf, &event)
        if err != nil {
                return err
        }
        return bucket.Put(timestampScratchSpace, eventBuf.Bytes())
}

// ForwardingEventQuery represents a query to the forwarding log payment
// circuit time series database. The query allows a caller to retrieve all
// records for a particular time slice, offset in that time slice, limiting the
// total number of responses returned.
type ForwardingEventQuery struct {
        // StartTime is the start time of the time slice.
        StartTime time.Time

        // EndTime is the end time of the time slice.
        EndTime time.Time

        // IndexOffset is the offset within the time slice to start at. This
        // can be used to start the response at a particular record.
        IndexOffset uint32

        // NumMaxEvents is the max number of events to return.
        NumMaxEvents uint32
}

// ForwardingLogTimeSlice is the response to a forwarding query. It includes
// the original query, the set  events that match the query, and an integer
// which represents the offset index of the last item in the set of returned
// events. This integer allows callers to resume their query using this offset
// in the event that the query's response exceeds the max number of returnable
// events.
type ForwardingLogTimeSlice struct {
        ForwardingEventQuery

        // ForwardingEvents is the set of events in our time series that answer
        // the query embedded above.
        ForwardingEvents []ForwardingEvent

        // LastIndexOffset is the index of the last element in the set of
        // returned ForwardingEvents above. Callers can use this to resume
        // their query in the event that the time slice has too many events to
        // fit into a single response.
        LastIndexOffset uint32
}

// Query allows a caller to query the forwarding event time series for a
// particular time slice. The caller can control the precise time as well as
// the number of events to be returned.
//
// TODO(roasbeef): rename?
func (f *ForwardingLog) Query(q ForwardingEventQuery) (ForwardingLogTimeSlice,
        error) {

        var resp ForwardingLogTimeSlice

        // If the user provided an index offset, then we'll not know how many
        // records we need to skip. We'll also keep track of the record offset
        // as that's part of the final return value.
        recordsToSkip := q.IndexOffset
        recordOffset := q.IndexOffset

        err := kvdb.View(f.db, func(tx kvdb.RTx) error {
                // If the bucket wasn't found, then there aren't any events to
                // be returned.
                logBucket := tx.ReadBucket(forwardingLogBucket)
                if logBucket == nil {
                        return ErrNoForwardingEvents
                }

                // We'll be using a cursor to seek into the database, so we'll
                // populate byte slices that represent the start of the key
                // space we're interested in, and the end.
                var startTime, endTime [8]byte
                byteOrder.PutUint64(startTime[:], uint64(q.StartTime.UnixNano()))
                byteOrder.PutUint64(endTime[:], uint64(q.EndTime.UnixNano()))

                // If we know that a set of log events exists, then we'll begin
                // our seek through the log in order to satisfy the query.
                // We'll continue until either we reach the end of the range,
                // or reach our max number of events.
                logCursor := logBucket.ReadCursor()
                timestamp, eventBytes := logCursor.Seek(startTime[:])
                //nolint:ll
                for ; timestamp != nil && bytes.Compare(timestamp, endTime[:]) <= 0; timestamp, eventBytes = logCursor.Next() {
                        // If our current return payload exceeds the max number
                        // of events, then we'll exit now.
                        if uint32(len(resp.ForwardingEvents)) >= q.NumMaxEvents {
                                return nil
                        }

                        // If we're not yet past the user defined offset, then
                        // we'll continue to seek forward.
                        if recordsToSkip > 0 {
                                recordsToSkip--
                                continue
                        }

                        // At this point, we've skipped enough records to start
                        // to collate our query. For each record, we'll
                        // increment the final record offset so the querier can
                        // utilize pagination to seek further.
                        readBuf := bytes.NewReader(eventBytes)
                        if readBuf.Len() == 0 {
                                continue
                        }

                        currentTime := time.Unix(
                                0, int64(byteOrder.Uint64(timestamp)),
                        )

                        var event ForwardingEvent
                        err := decodeForwardingEvent(readBuf, &event)
                        if err != nil {
                                return err
                        }

                        event.Timestamp = currentTime
                        resp.ForwardingEvents = append(
                                resp.ForwardingEvents, event,
                        )

                        recordOffset++
                }

                return nil
        }, func() {
                resp = ForwardingLogTimeSlice{
                        ForwardingEventQuery: q,
                }
        })
        if err != nil && err != ErrNoForwardingEvents {
                return ForwardingLogTimeSlice{}, err
        }

        resp.LastIndexOffset = recordOffset

        return resp, nil
}

// makeUniqueTimestamps takes a slice of forwarding events, sorts it by the
// event timestamps and then makes sure there are no duplicates in the
// timestamps. If duplicates are found, some of the timestamps are increased on
// the nanosecond scale until only unique values remain. This is a fix to
// address the problem that in some environments (looking at you, Windows) the
// system clock has such a bad resolution that two serial invocations of
// time.Now() might return the same timestamp, even if some time has elapsed
// between the calls.
func makeUniqueTimestamps(events []ForwardingEvent) {
        sort.Slice(events, func(i, j int) bool {
                return events[i].Timestamp.Before(events[j].Timestamp)
        })

        // Now that we know the events are sorted by timestamp, we can go
        // through the list and fix all duplicates until only unique values
        // remain.
        for outer := 0; outer < len(events)-1; outer++ {
                current := events[outer].Timestamp.UnixNano()
                next := events[outer+1].Timestamp.UnixNano()

                // We initially sorted the slice. So if the current is now
                // greater or equal to the next one, it's either because it's a
                // duplicate or because we increased the current in the last
                // iteration.
                if current >= next {
                        next = current + 1
                        events[outer+1].Timestamp = time.Unix(0, next)
                }
        }
}

1	package channeldb
2
3	import (
4	"bytes"
5	"errors"
6	"io"
7	"sort"
8	"time"
9
10	"github.com/btcsuite/btcwallet/walletdb"
11	"github.com/lightningnetwork/lnd/fn/v2"
12	"github.com/lightningnetwork/lnd/kvdb"
13	"github.com/lightningnetwork/lnd/lnwire"
14	)
15
16	var (
17	// forwardingLogBucket is the bucket that we'll use to store the
18	// forwarding log. The forwarding log contains a time series database
19	// of the forwarding history of a lightning daemon. Each key within the
20	// bucket is a timestamp (in nano seconds since the unix epoch), and
21	// the value a slice of a forwarding event for that timestamp.
22	forwardingLogBucket = []byte("circuit-fwd-log")
23	)
24
25	const (
26	// forwardingEventSize is the size of a forwarding event. The breakdown
27	// is as follows:
28	//
29	// * 8 byte incoming chan ID \|\| 8 byte outgoing chan ID \|\| 8 byte value in
30	// \|\| 8 byte value out \|\| 8 byte incoming htlc id \|\| 8 byte
31	// outgoing htlc id
32	//
33	// From the value in and value out, callers can easily compute the
34	// total fee extract from a forwarding event.
35	forwardingEventSize = 48
36
37	// MaxResponseEvents is the max number of forwarding events that will
38	// be returned by a single query response. This size was selected to
39	// safely remain under gRPC's 4MiB message size response limit. As each
40	// full forwarding event (including the timestamp) is 40 bytes, we can
41	// safely return 50k entries in a single response.
42	MaxResponseEvents = 50000
43	)
44
45	// ForwardingLog returns an instance of the ForwardingLog object backed by the
46	// target database instance.
47	func (d DB) ForwardingLog() ForwardingLog {	×
48	return &ForwardingLog{	×
49	db: d,	×
50	}	×
51	}	×
52
53	// ForwardingLog is a time series database that logs the fulfillment of payment
54	// circuits by a lightning network daemon. The log contains a series of
55	// forwarding events which map a timestamp to a forwarding event. A forwarding
56	// event describes which channels were used to create+settle a circuit, and the
57	// amount involved. Subtracting the outgoing amount from the incoming amount
58	// reveals the fee charged for the forwarding service.
59	type ForwardingLog struct {
60	db *DB
61	}
62
63	// ForwardingEvent is an event in the forwarding log's time series. Each
64	// forwarding event logs the creation and tear-down of a payment circuit. A
65	// circuit is created once an incoming HTLC has been fully forwarded, and
66	// destroyed once the payment has been settled.
67	type ForwardingEvent struct {
68	// Timestamp is the settlement time of this payment circuit.
69	Timestamp time.Time
70
71	// IncomingChanID is the incoming channel ID of the payment circuit.
72	IncomingChanID lnwire.ShortChannelID
73
74	// OutgoingChanID is the outgoing channel ID of the payment circuit.
75	OutgoingChanID lnwire.ShortChannelID
76
77	// AmtIn is the amount of the incoming HTLC. Subtracting this from the
78	// outgoing amount gives the total fees of this payment circuit.
79	AmtIn lnwire.MilliSatoshi
80
81	// AmtOut is the amount of the outgoing HTLC. Subtracting the incoming
82	// amount from this gives the total fees for this payment circuit.
83	AmtOut lnwire.MilliSatoshi
84
85	// IncomingHtlcID is the ID of the incoming HTLC in the payment circuit.
86	// If this is not set, the value will be nil. This field is added in
87	// v0.20 and is made optional to make it backward compatible with
88	// existing forwarding events created before it's introduction.
89	IncomingHtlcID fn.Option[uint64]
90
91	// OutgoingHtlcID is the ID of the outgoing HTLC in the payment circuit.
92	// If this is not set, the value will be nil. This field is added in
93	// v0.20 and is made optional to make it backward compatible with
94	// existing forwarding events created before it's introduction.
95	OutgoingHtlcID fn.Option[uint64]
96	}
97
98	// encodeForwardingEvent writes out the target forwarding event to the passed
99	// io.Writer, using the expected DB format. Note that the timestamp isn't
100	// serialized as this will be the key value within the bucket.
101	func encodeForwardingEvent(w io.Writer, f *ForwardingEvent) error {	360✔
102	// We check for the HTLC IDs if they are set. If they are not,	360✔
103	// from v0.20 upward, we return an error to make it clear they are	360✔
104	// required.	360✔
105	incomingID, err := f.IncomingHtlcID.UnwrapOrErr(	360✔
106	errors.New("incoming HTLC ID must be set"),	360✔
107	)	360✔
108	if err != nil {	360✔
109	return err	×
110	}	×
111
112	outgoingID, err := f.OutgoingHtlcID.UnwrapOrErr(	360✔
113	errors.New("outgoing HTLC ID must be set"),	360✔
114	)	360✔
115	if err != nil {	360✔
116	return err	×
117	}	×
118
119	return WriteElements(	360✔
120	w, f.IncomingChanID, f.OutgoingChanID, f.AmtIn, f.AmtOut,	360✔
121	incomingID, outgoingID,	360✔
122	)	360✔
123	}
124
125	// decodeForwardingEvent attempts to decode the raw bytes of a serialized
126	// forwarding event into the target ForwardingEvent. Note that the timestamp
127	// won't be decoded, as the caller is expected to set this due to the bucket
128	// structure of the forwarding log.
129	func decodeForwardingEvent(r io.Reader, f *ForwardingEvent) error {	270✔
130	// Decode the original fields of the forwarding event.	270✔
131	err := ReadElements(	270✔
132	r, &f.IncomingChanID, &f.OutgoingChanID, &f.AmtIn, &f.AmtOut,	270✔
133	)	270✔
134	if err != nil {	270✔
135	return err	×
136	}	×
137
138	// Decode the incoming and outgoing htlc IDs. For backward compatibility
139	// with older records that don't have these fields, we handle EOF by
140	// setting the ID to nil. Any other error is treated as a read failure.
141	var incomingHtlcID, outgoingHtlcID uint64	270✔
142	err = ReadElements(r, &incomingHtlcID, &outgoingHtlcID)	270✔
143	switch {	270✔
144	case err == nil:	260✔
145	f.IncomingHtlcID = fn.Some(incomingHtlcID)	260✔
146	f.OutgoingHtlcID = fn.Some(outgoingHtlcID)	260✔
147		260✔
148	return nil	260✔
149
150	case errors.Is(err, io.EOF):	10✔
151	return nil	10✔
152
153	default:	×
154	return err	×
155	}
156	}
157
158	// AddForwardingEvents adds a series of forwarding events to the database.
159	// Before inserting, the set of events will be sorted according to their
160	// timestamp. This ensures that all writes to disk are sequential.
161	func (f *ForwardingLog) AddForwardingEvents(events []ForwardingEvent) error {	5✔
162	// Before we create the database transaction, we'll ensure that the set	5✔
163	// of forwarding events are properly sorted according to their	5✔
164	// timestamp and that no duplicate timestamps exist to avoid collisions	5✔
165	// in the key we are going to store the events under.	5✔
166	makeUniqueTimestamps(events)	5✔
167		5✔
168	var timestamp [8]byte	5✔
169		5✔
170	return kvdb.Batch(f.db.Backend, func(tx kvdb.RwTx) error {	10✔
171	// First, we'll fetch the bucket that stores our time series	5✔
172	// log.	5✔
173	logBucket, err := tx.CreateTopLevelBucket(	5✔
174	forwardingLogBucket,	5✔
175	)	5✔
176	if err != nil {	5✔
177	return err	×
178	}	×
179
180	// With the bucket obtained, we can now begin to write out the
181	// series of events.
182	for _, event := range events {	365✔
183	err := storeEvent(logBucket, event, timestamp[:])	360✔
184	if err != nil {	360✔
185	return err	×
186	}	×
187	}
188
189	return nil	5✔
190	})
191	}
192
193	// storeEvent tries to store a forwarding event into the given bucket by trying
194	// to avoid collisions. If a key for the event timestamp already exists in the
195	// database, the timestamp is incremented in nanosecond intervals until a "free"
196	// slot is found.
197	func storeEvent(bucket walletdb.ReadWriteBucket, event ForwardingEvent,
198	timestampScratchSpace []byte) error {	360✔
199		360✔
200	// First, we'll serialize this timestamp into our	360✔
201	// timestamp buffer.	360✔
202	byteOrder.PutUint64(	360✔
203	timestampScratchSpace, uint64(event.Timestamp.UnixNano()),	360✔
204	)	360✔
205		360✔
206	// Next we'll loop until we find a "free" slot in the bucket to store	360✔
207	// the event under. This should almost never happen unless we're running	360✔
208	// on a system that has a very bad system clock that doesn't properly	360✔
209	// resolve to nanosecond scale. We try up to 100 times (which would come	360✔
210	// to a maximum shift of 0.1 microsecond which is acceptable for most	360✔
211	// use cases). If we don't find a free slot, we just give up and let	360✔
212	// the collision happen. Something must be wrong with the data in that	360✔
213	// case, even on a very fast machine forwarding payments _will_ take a	360✔
214	// few microseconds at least so we should find a nanosecond slot	360✔
215	// somewhere.	360✔
216	const maxTries = 100	360✔
217	tries := 0	360✔
218	for tries < maxTries {	1,120✔
219	val := bucket.Get(timestampScratchSpace)	760✔
220	if val == nil {	1,120✔
221	break	360✔
222	}
223
224	// Collision, try the next nanosecond timestamp.
225	nextNano := event.Timestamp.UnixNano() + 1	400✔
226	event.Timestamp = time.Unix(0, nextNano)	400✔
227	byteOrder.PutUint64(timestampScratchSpace, uint64(nextNano))	400✔
228	tries++	400✔
229	}
230
231	// With the key encoded, we'll then encode the event
232	// into our buffer, then write it out to disk.
233	var eventBytes [forwardingEventSize]byte	360✔
234	eventBuf := bytes.NewBuffer(eventBytes[0:0:forwardingEventSize])	360✔
235	err := encodeForwardingEvent(eventBuf, &event)	360✔
236	if err != nil {	360✔
237	return err	×
238	}	×
239	return bucket.Put(timestampScratchSpace, eventBuf.Bytes())	360✔
240	}
241
242	// ForwardingEventQuery represents a query to the forwarding log payment
243	// circuit time series database. The query allows a caller to retrieve all
244	// records for a particular time slice, offset in that time slice, limiting the
245	// total number of responses returned.
246	type ForwardingEventQuery struct {
247	// StartTime is the start time of the time slice.
248	StartTime time.Time
249
250	// EndTime is the end time of the time slice.
251	EndTime time.Time
252
253	// IndexOffset is the offset within the time slice to start at. This
254	// can be used to start the response at a particular record.
255	IndexOffset uint32
256
257	// NumMaxEvents is the max number of events to return.
258	NumMaxEvents uint32
259	}
260
261	// ForwardingLogTimeSlice is the response to a forwarding query. It includes
262	// the original query, the set events that match the query, and an integer
263	// which represents the offset index of the last item in the set of returned
264	// events. This integer allows callers to resume their query using this offset
265	// in the event that the query's response exceeds the max number of returnable
266	// events.
267	type ForwardingLogTimeSlice struct {
268	ForwardingEventQuery
269
270	// ForwardingEvents is the set of events in our time series that answer
271	// the query embedded above.
272	ForwardingEvents []ForwardingEvent
273
274	// LastIndexOffset is the index of the last element in the set of
275	// returned ForwardingEvents above. Callers can use this to resume
276	// their query in the event that the time slice has too many events to
277	// fit into a single response.
278	LastIndexOffset uint32
279	}
280
281	// Query allows a caller to query the forwarding event time series for a
282	// particular time slice. The caller can control the precise time as well as
283	// the number of events to be returned.
284	//
285	// TODO(roasbeef): rename?
286	func (f *ForwardingLog) Query(q ForwardingEventQuery) (ForwardingLogTimeSlice,
287	error) {	6✔
288		6✔
289	var resp ForwardingLogTimeSlice	6✔
290		6✔
291	// If the user provided an index offset, then we'll not know how many	6✔
292	// records we need to skip. We'll also keep track of the record offset	6✔
293	// as that's part of the final return value.	6✔
294	recordsToSkip := q.IndexOffset	6✔
295	recordOffset := q.IndexOffset	6✔
296		6✔
297	err := kvdb.View(f.db, func(tx kvdb.RTx) error {	12✔
298	// If the bucket wasn't found, then there aren't any events to	6✔
299	// be returned.	6✔
300	logBucket := tx.ReadBucket(forwardingLogBucket)	6✔
301	if logBucket == nil {	6✔
302	return ErrNoForwardingEvents	×
303	}	×
304
305	// We'll be using a cursor to seek into the database, so we'll
306	// populate byte slices that represent the start of the key
307	// space we're interested in, and the end.
308	var startTime, endTime [8]byte	6✔
309	byteOrder.PutUint64(startTime[:], uint64(q.StartTime.UnixNano()))	6✔
310	byteOrder.PutUint64(endTime[:], uint64(q.EndTime.UnixNano()))	6✔
311		6✔
312	// If we know that a set of log events exists, then we'll begin	6✔
313	// our seek through the log in order to satisfy the query.	6✔
314	// We'll continue until either we reach the end of the range,	6✔
315	// or reach our max number of events.	6✔
316	logCursor := logBucket.ReadCursor()	6✔
317	timestamp, eventBytes := logCursor.Seek(startTime[:])	6✔
318	//nolint:ll	6✔
319	for ; timestamp != nil && bytes.Compare(timestamp, endTime[:]) <= 0; timestamp, eventBytes = logCursor.Next() {	288✔
320	// If our current return payload exceeds the max number	282✔
321	// of events, then we'll exit now.	282✔
322	if uint32(len(resp.ForwardingEvents)) >= q.NumMaxEvents {	284✔
323	return nil	2✔
324	}	2✔
325
326	// If we're not yet past the user defined offset, then
327	// we'll continue to seek forward.
328	if recordsToSkip > 0 {	290✔
329	recordsToSkip--	10✔
330	continue	10✔
331	}
332
333	// At this point, we've skipped enough records to start
334	// to collate our query. For each record, we'll
335	// increment the final record offset so the querier can
336	// utilize pagination to seek further.
337	readBuf := bytes.NewReader(eventBytes)	270✔
338	if readBuf.Len() == 0 {	270✔
339	continue	×
340	}
341
342	currentTime := time.Unix(	270✔
343	0, int64(byteOrder.Uint64(timestamp)),	270✔
344	)	270✔
345		270✔
346	var event ForwardingEvent	270✔
347	err := decodeForwardingEvent(readBuf, &event)	270✔
348	if err != nil {	270✔
349	return err	×
350	}	×
351
352	event.Timestamp = currentTime	270✔
353	resp.ForwardingEvents = append(	270✔
354	resp.ForwardingEvents, event,	270✔
355	)	270✔
356		270✔
357	recordOffset++	270✔
358	}
359
360	return nil	4✔
361	}, func() {	6✔
362	resp = ForwardingLogTimeSlice{	6✔
363	ForwardingEventQuery: q,	6✔
364	}	6✔
365	})	6✔
366	if err != nil && err != ErrNoForwardingEvents {	6✔
367	return ForwardingLogTimeSlice{}, err	×
368	}	×
369
370	resp.LastIndexOffset = recordOffset	6✔
371		6✔
372	return resp, nil	6✔
373	}
374
375	// makeUniqueTimestamps takes a slice of forwarding events, sorts it by the
376	// event timestamps and then makes sure there are no duplicates in the
377	// timestamps. If duplicates are found, some of the timestamps are increased on
378	// the nanosecond scale until only unique values remain. This is a fix to
379	// address the problem that in some environments (looking at you, Windows) the
380	// system clock has such a bad resolution that two serial invocations of
381	// time.Now() might return the same timestamp, even if some time has elapsed
382	// between the calls.
383	func makeUniqueTimestamps(events []ForwardingEvent) {	6✔
384	sort.Slice(events, func(i, j int) bool {	411✔
385	return events[i].Timestamp.Before(events[j].Timestamp)	405✔
386	})	405✔
387
388	// Now that we know the events are sorted by timestamp, we can go
389	// through the list and fix all duplicates until only unique values
390	// remain.
391	for outer := 0; outer < len(events)-1; outer++ {	368✔
392	current := events[outer].Timestamp.UnixNano()	362✔
393	next := events[outer+1].Timestamp.UnixNano()	362✔
394		362✔
395	// We initially sorted the slice. So if the current is now	362✔
396	// greater or equal to the next one, it's either because it's a	362✔
397	// duplicate or because we increased the current in the last	362✔
398	// iteration.	362✔
399	if current >= next {	367✔
400	next = current + 1	5✔
401	events[outer+1].Timestamp = time.Unix(0, next)	5✔
402	}	5✔
403	}
404	}

lightningnetwork / lnd / 15635919293

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