lnd.xprv/channeldb/invoices.go
Wilmer Paulino f315b5b0d1
channeldb: support querying for invoices within a specific time range
In this commit, we introduce support for querying the database for invoices
that occurred within a specific add index range. The query format includes an
index to start with and a limit on the number of returned results.

Co-authored-by: Valentine Wallace <valentine.m.wallace@gmail.com>
2018-08-21 18:00:08 -07:00

866 lines
25 KiB
Go

package channeldb
import (
"bytes"
"crypto/sha256"
"encoding/binary"
"fmt"
"io"
"time"
"github.com/btcsuite/btcd/wire"
"github.com/coreos/bbolt"
"github.com/lightningnetwork/lnd/lnwire"
)
var (
// invoiceBucket is the name of the bucket within the database that
// stores all data related to invoices no matter their final state.
// Within the invoice bucket, each invoice is keyed by its invoice ID
// which is a monotonically increasing uint32.
invoiceBucket = []byte("invoices")
// paymentHashIndexBucket is the name of the sub-bucket within the
// invoiceBucket which indexes all invoices by their payment hash. The
// payment hash is the sha256 of the invoice's payment preimage. This
// index is used to detect duplicates, and also to provide a fast path
// for looking up incoming HTLCs to determine if we're able to settle
// them fully.
//
// maps: payHash => invoiceKey
invoiceIndexBucket = []byte("paymenthashes")
// numInvoicesKey is the name of key which houses the auto-incrementing
// invoice ID which is essentially used as a primary key. With each
// invoice inserted, the primary key is incremented by one. This key is
// stored within the invoiceIndexBucket. Within the invoiceBucket
// invoices are uniquely identified by the invoice ID.
numInvoicesKey = []byte("nik")
// addIndexBucket is an index bucket that we'll use to create a
// monotonically increasing set of add indexes. Each time we add a new
// invoice, this sequence number will be incremented and then populated
// within the new invoice.
//
// In addition to this sequence number, we map:
//
// addIndexNo => invoiceKey
addIndexBucket = []byte("invoice-add-index")
// settleIndexBucket is an index bucket that we'll use to create a
// monotonically increasing integer for tracking a "settle index". Each
// time an invoice is settled, this sequence number will be incremented
// as populate within the newly settled invoice.
//
// In addition to this sequence number, we map:
//
// settleIndexNo => invoiceKey
settleIndexBucket = []byte("invoice-settle-index")
)
const (
// MaxMemoSize is maximum size of the memo field within invoices stored
// in the database.
MaxMemoSize = 1024
// MaxReceiptSize is the maximum size of the payment receipt stored
// within the database along side incoming/outgoing invoices.
MaxReceiptSize = 1024
// MaxPaymentRequestSize is the max size of a payment request for
// this invoice.
// TODO(halseth): determine the max length payment request when field
// lengths are final.
MaxPaymentRequestSize = 4096
)
// ContractTerm is a companion struct to the Invoice struct. This struct houses
// the necessary conditions required before the invoice can be considered fully
// settled by the payee.
type ContractTerm struct {
// PaymentPreimage is the preimage which is to be revealed in the
// occasion that an HTLC paying to the hash of this preimage is
// extended.
PaymentPreimage [32]byte
// Value is the expected amount of milli-satoshis to be paid to an HTLC
// which can be satisfied by the above preimage.
Value lnwire.MilliSatoshi
// Settled indicates if this particular contract term has been fully
// settled by the payer.
Settled bool
}
// Invoice is a payment invoice generated by a payee in order to request
// payment for some good or service. The inclusion of invoices within Lightning
// creates a payment work flow for merchants very similar to that of the
// existing financial system within PayPal, etc. Invoices are added to the
// database when a payment is requested, then can be settled manually once the
// payment is received at the upper layer. For record keeping purposes,
// invoices are never deleted from the database, instead a bit is toggled
// denoting the invoice has been fully settled. Within the database, all
// invoices must have a unique payment hash which is generated by taking the
// sha256 of the payment preimage.
type Invoice struct {
// Memo is an optional memo to be stored along side an invoice. The
// memo may contain further details pertaining to the invoice itself,
// or any other message which fits within the size constraints.
Memo []byte
// Receipt is an optional field dedicated for storing a
// cryptographically binding receipt of payment.
//
// TODO(roasbeef): document scheme.
Receipt []byte
// PaymentRequest is an optional field where a payment request created
// for this invoice can be stored.
PaymentRequest []byte
// CreationDate is the exact time the invoice was created.
CreationDate time.Time
// SettleDate is the exact time the invoice was settled.
SettleDate time.Time
// Terms are the contractual payment terms of the invoice. Once all the
// terms have been satisfied by the payer, then the invoice can be
// considered fully fulfilled.
//
// TODO(roasbeef): later allow for multiple terms to fulfill the final
// invoice: payment fragmentation, etc.
Terms ContractTerm
// AddIndex is an auto-incrementing integer that acts as a
// monotonically increasing sequence number for all invoices created.
// Clients can then use this field as a "checkpoint" of sorts when
// implementing a streaming RPC to notify consumers of instances where
// an invoice has been added before they re-connected.
//
// NOTE: This index starts at 1.
AddIndex uint64
// SettleIndex is an auto-incrementing integer that acts as a
// monotonically increasing sequence number for all settled invoices.
// Clients can then use this field as a "checkpoint" of sorts when
// implementing a streaming RPC to notify consumers of instances where
// an invoice has been settled before they re-connected.
//
// NOTE: This index starts at 1.
SettleIndex uint64
// AmtPaid is the final amount that we ultimately accepted for pay for
// this invoice. We specify this value independently as it's possible
// that the invoice originally didn't specify an amount, or the sender
// overpaid.
AmtPaid lnwire.MilliSatoshi
}
func validateInvoice(i *Invoice) error {
if len(i.Memo) > MaxMemoSize {
return fmt.Errorf("max length a memo is %v, and invoice "+
"of length %v was provided", MaxMemoSize, len(i.Memo))
}
if len(i.Receipt) > MaxReceiptSize {
return fmt.Errorf("max length a receipt is %v, and invoice "+
"of length %v was provided", MaxReceiptSize,
len(i.Receipt))
}
if len(i.PaymentRequest) > MaxPaymentRequestSize {
return fmt.Errorf("max length of payment request is %v, length "+
"provided was %v", MaxPaymentRequestSize,
len(i.PaymentRequest))
}
return nil
}
// AddInvoice inserts the targeted invoice into the database. If the invoice
// has *any* payment hashes which already exists within the database, then the
// insertion will be aborted and rejected due to the strict policy banning any
// duplicate payment hashes.
func (d *DB) AddInvoice(newInvoice *Invoice) (uint64, error) {
if err := validateInvoice(newInvoice); err != nil {
return 0, err
}
var invoiceAddIndex uint64
err := d.Update(func(tx *bolt.Tx) error {
invoices, err := tx.CreateBucketIfNotExists(invoiceBucket)
if err != nil {
return err
}
invoiceIndex, err := invoices.CreateBucketIfNotExists(
invoiceIndexBucket,
)
if err != nil {
return err
}
addIndex, err := invoices.CreateBucketIfNotExists(
addIndexBucket,
)
if err != nil {
return err
}
// Ensure that an invoice an identical payment hash doesn't
// already exist within the index.
paymentHash := sha256.Sum256(
newInvoice.Terms.PaymentPreimage[:],
)
if invoiceIndex.Get(paymentHash[:]) != nil {
return ErrDuplicateInvoice
}
// If the current running payment ID counter hasn't yet been
// created, then create it now.
var invoiceNum uint32
invoiceCounter := invoiceIndex.Get(numInvoicesKey)
if invoiceCounter == nil {
var scratch [4]byte
byteOrder.PutUint32(scratch[:], invoiceNum)
err := invoiceIndex.Put(numInvoicesKey, scratch[:])
if err != nil {
return nil
}
} else {
invoiceNum = byteOrder.Uint32(invoiceCounter)
}
newIndex, err := putInvoice(
invoices, invoiceIndex, addIndex, newInvoice, invoiceNum,
)
if err != nil {
return err
}
invoiceAddIndex = newIndex
return nil
})
if err != nil {
return 0, err
}
return invoiceAddIndex, err
}
// InvoicesAddedSince can be used by callers to seek into the event time series
// of all the invoices added in the database. The specified sinceAddIndex
// should be the highest add index that the caller knows of. This method will
// return all invoices with an add index greater than the specified
// sinceAddIndex.
//
// NOTE: The index starts from 1, as a result. We enforce that specifying a
// value below the starting index value is a noop.
func (d *DB) InvoicesAddedSince(sinceAddIndex uint64) ([]Invoice, error) {
var newInvoices []Invoice
// If an index of zero was specified, then in order to maintain
// backwards compat, we won't send out any new invoices.
if sinceAddIndex == 0 {
return newInvoices, nil
}
var startIndex [8]byte
byteOrder.PutUint64(startIndex[:], sinceAddIndex)
err := d.DB.View(func(tx *bolt.Tx) error {
invoices := tx.Bucket(invoiceBucket)
if invoices == nil {
return ErrNoInvoicesCreated
}
addIndex := invoices.Bucket(addIndexBucket)
if addIndex == nil {
return ErrNoInvoicesCreated
}
// We'll now run through each entry in the add index starting
// at our starting index. We'll continue until we reach the
// very end of the current key space.
invoiceCursor := addIndex.Cursor()
// We'll seek to the starting index, then manually advance the
// cursor in order to skip the entry with the since add index.
invoiceCursor.Seek(startIndex[:])
addSeqNo, invoiceKey := invoiceCursor.Next()
for ; addSeqNo != nil && bytes.Compare(addSeqNo, startIndex[:]) > 0; addSeqNo, invoiceKey = invoiceCursor.Next() {
// For each key found, we'll look up the actual
// invoice, then accumulate it into our return value.
invoice, err := fetchInvoice(invoiceKey, invoices)
if err != nil {
return err
}
newInvoices = append(newInvoices, invoice)
}
return nil
})
switch {
// If no invoices have been created, then we'll return the empty set of
// invoices.
case err == ErrNoInvoicesCreated:
case err != nil:
return nil, err
}
return newInvoices, nil
}
// LookupInvoice attempts to look up an invoice according to its 32 byte
// payment hash. If an invoice which can settle the HTLC identified by the
// passed payment hash isn't found, then an error is returned. Otherwise, the
// full invoice is returned. Before setting the incoming HTLC, the values
// SHOULD be checked to ensure the payer meets the agreed upon contractual
// terms of the payment.
func (d *DB) LookupInvoice(paymentHash [32]byte) (Invoice, error) {
var invoice Invoice
err := d.View(func(tx *bolt.Tx) error {
invoices := tx.Bucket(invoiceBucket)
if invoices == nil {
return ErrNoInvoicesCreated
}
invoiceIndex := invoices.Bucket(invoiceIndexBucket)
if invoiceIndex == nil {
return ErrNoInvoicesCreated
}
// Check the invoice index to see if an invoice paying to this
// hash exists within the DB.
invoiceNum := invoiceIndex.Get(paymentHash[:])
if invoiceNum == nil {
return ErrInvoiceNotFound
}
// An invoice matching the payment hash has been found, so
// retrieve the record of the invoice itself.
i, err := fetchInvoice(invoiceNum, invoices)
if err != nil {
return err
}
invoice = i
return nil
})
if err != nil {
return invoice, err
}
return invoice, nil
}
// FetchAllInvoices returns all invoices currently stored within the database.
// If the pendingOnly param is true, then only unsettled invoices will be
// returned, skipping all invoices that are fully settled.
func (d *DB) FetchAllInvoices(pendingOnly bool) ([]Invoice, error) {
var invoices []Invoice
err := d.View(func(tx *bolt.Tx) error {
invoiceB := tx.Bucket(invoiceBucket)
if invoiceB == nil {
return ErrNoInvoicesCreated
}
// Iterate through the entire key space of the top-level
// invoice bucket. If key with a non-nil value stores the next
// invoice ID which maps to the corresponding invoice.
return invoiceB.ForEach(func(k, v []byte) error {
if v == nil {
return nil
}
invoiceReader := bytes.NewReader(v)
invoice, err := deserializeInvoice(invoiceReader)
if err != nil {
return err
}
if pendingOnly && invoice.Terms.Settled {
return nil
}
invoices = append(invoices, invoice)
return nil
})
})
if err != nil {
return nil, err
}
return invoices, nil
}
// InvoiceQuery represents a query to the invoice database. The query allows a
// caller to retrieve all invoices starting from a particular add index and
// limit the number of results returned.
type InvoiceQuery struct {
// IndexOffset is the offset within the add indices to start at. This
// can be used to start the response at a particular invoice.
IndexOffset uint32
// NumMaxInvoices is the maximum number of invoices that should be
// starting from the add index.
NumMaxInvoices uint32
// PendingOnly, if set, returns unsettled invoices starting from the
// add index.
PendingOnly bool
}
// InvoiceSlice is the response to a invoice query. It includes the original
// query, the set of invoices that match the query, and an integer which
// represents the offset index of the last item in the set of returned invoices.
// This integer allows callers to resume their query using this offset in the
// event that the query's response exceeds the maximum number of returnable
// invoices.
type InvoiceSlice struct {
InvoiceQuery
// Invoices is the set of invoices that matched the query above.
Invoices []*Invoice
// LastIndexOffset is the index of the last element in the set of
// returned Invoices 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
}
// QueryInvoices allows a caller to query the invoice database for invoices
// within the specified add index range.
func (d *DB) QueryInvoices(q InvoiceQuery) (InvoiceSlice, error) {
resp := InvoiceSlice{
InvoiceQuery: q,
}
// If the caller 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.
invoicesToSkip := q.IndexOffset
invoiceOffset := q.IndexOffset
err := d.View(func(tx *bolt.Tx) error {
// If the bucket wasn't found, then there aren't any invoices
// within the database yet, so we can simply exit.
invoices := tx.Bucket(invoiceBucket)
if invoices == nil {
return ErrNoInvoicesCreated
}
invoiceAddedIndex := invoices.Bucket(addIndexBucket)
if invoiceAddedIndex == nil {
return ErrNoInvoicesCreated
}
// 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.
var startIndex [8]byte
switch q.PendingOnly {
case true:
// We have to start from the beginning so we know
// how many pending invoices we're skipping.
byteOrder.PutUint64(startIndex[:], uint64(1))
default:
// We can seek right to the invoice offset we want
// to start with.
invoicesToSkip = 0
byteOrder.PutUint64(startIndex[:], uint64(invoiceOffset+1))
}
// If we know that a set of invoices exists, then we'll begin
// our seek through the bucket 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.
cursor := invoiceAddedIndex.Cursor()
_, invoiceKey := cursor.Seek(startIndex[:])
for ; invoiceKey != nil; _, invoiceKey = cursor.Next() {
// If our current return payload exceeds the max number
// of invoices, then we'll exit now.
if uint32(len(resp.Invoices)) >= q.NumMaxInvoices {
return nil
}
invoice, err := fetchInvoice(invoiceKey, invoices)
if err != nil {
return err
}
// Skip any settled invoices if the caller is only
// interested in unsettled.
if q.PendingOnly && invoice.Terms.Settled {
continue
}
// If we're not yet past the user defined offset, then
// we'll continue to seek forward.
if invoicesToSkip > 0 {
invoicesToSkip--
continue
}
// At this point, we've exhausted the offset, so we'll
// begin collecting invoices found within the range.
resp.Invoices = append(resp.Invoices, &invoice)
invoiceOffset++
}
return nil
})
if err != nil && err != ErrNoInvoicesCreated {
return resp, err
}
// Finally, record the index of the last invoice added so that the
// caller can resume from this point later on.
resp.LastIndexOffset = invoiceOffset
return resp, nil
}
// SettleInvoice attempts to mark an invoice corresponding to the passed
// payment hash as fully settled. If an invoice matching the passed payment
// hash doesn't existing within the database, then the action will fail with a
// "not found" error.
func (d *DB) SettleInvoice(paymentHash [32]byte,
amtPaid lnwire.MilliSatoshi) (*Invoice, error) {
var settledInvoice *Invoice
err := d.Update(func(tx *bolt.Tx) error {
invoices, err := tx.CreateBucketIfNotExists(invoiceBucket)
if err != nil {
return err
}
invoiceIndex, err := invoices.CreateBucketIfNotExists(
invoiceIndexBucket,
)
if err != nil {
return err
}
settleIndex, err := invoices.CreateBucketIfNotExists(
settleIndexBucket,
)
if err != nil {
return err
}
// Check the invoice index to see if an invoice paying to this
// hash exists within the DB.
invoiceNum := invoiceIndex.Get(paymentHash[:])
if invoiceNum == nil {
return ErrInvoiceNotFound
}
invoice, err := settleInvoice(
invoices, settleIndex, invoiceNum, amtPaid,
)
if err != nil {
return err
}
settledInvoice = invoice
return nil
})
if err != nil {
return nil, err
}
return settledInvoice, nil
}
// InvoicesSettledSince can be used by callers to catch up any settled invoices
// they missed within the settled invoice time series. We'll return all known
// settled invoice that have a settle index higher than the passed
// sinceSettleIndex.
//
// NOTE: The index starts from 1, as a result. We enforce that specifying a
// value below the starting index value is a noop.
func (d *DB) InvoicesSettledSince(sinceSettleIndex uint64) ([]Invoice, error) {
var settledInvoices []Invoice
// If an index of zero was specified, then in order to maintain
// backwards compat, we won't send out any new invoices.
if sinceSettleIndex == 0 {
return settledInvoices, nil
}
var startIndex [8]byte
byteOrder.PutUint64(startIndex[:], sinceSettleIndex)
err := d.DB.View(func(tx *bolt.Tx) error {
invoices := tx.Bucket(invoiceBucket)
if invoices == nil {
return ErrNoInvoicesCreated
}
settleIndex := invoices.Bucket(settleIndexBucket)
if settleIndex == nil {
return ErrNoInvoicesCreated
}
// We'll now run through each entry in the add index starting
// at our starting index. We'll continue until we reach the
// very end of the current key space.
invoiceCursor := settleIndex.Cursor()
// We'll seek to the starting index, then manually advance the
// cursor in order to skip the entry with the since add index.
invoiceCursor.Seek(startIndex[:])
seqNo, invoiceKey := invoiceCursor.Next()
for ; seqNo != nil && bytes.Compare(seqNo, startIndex[:]) > 0; seqNo, invoiceKey = invoiceCursor.Next() {
// For each key found, we'll look up the actual
// invoice, then accumulate it into our return value.
invoice, err := fetchInvoice(invoiceKey, invoices)
if err != nil {
return err
}
settledInvoices = append(settledInvoices, invoice)
}
return nil
})
if err != nil {
return nil, err
}
return settledInvoices, nil
}
func putInvoice(invoices, invoiceIndex, addIndex *bolt.Bucket,
i *Invoice, invoiceNum uint32) (uint64, error) {
// Create the invoice key which is just the big-endian representation
// of the invoice number.
var invoiceKey [4]byte
byteOrder.PutUint32(invoiceKey[:], invoiceNum)
// Increment the num invoice counter index so the next invoice bares
// the proper ID.
var scratch [4]byte
invoiceCounter := invoiceNum + 1
byteOrder.PutUint32(scratch[:], invoiceCounter)
if err := invoiceIndex.Put(numInvoicesKey, scratch[:]); err != nil {
return 0, err
}
// Add the payment hash to the invoice index. This will let us quickly
// identify if we can settle an incoming payment, and also to possibly
// allow a single invoice to have multiple payment installations.
paymentHash := sha256.Sum256(i.Terms.PaymentPreimage[:])
err := invoiceIndex.Put(paymentHash[:], invoiceKey[:])
if err != nil {
return 0, err
}
// Next, we'll obtain the next add invoice index (sequence
// number), so we can properly place this invoice within this
// event stream.
nextAddSeqNo, err := addIndex.NextSequence()
if err != nil {
return 0, err
}
// With the next sequence obtained, we'll updating the event series in
// the add index bucket to map this current add counter to the index of
// this new invoice.
var seqNoBytes [8]byte
byteOrder.PutUint64(seqNoBytes[:], nextAddSeqNo)
if err := addIndex.Put(seqNoBytes[:], invoiceKey[:]); err != nil {
return 0, err
}
i.AddIndex = nextAddSeqNo
// Finally, serialize the invoice itself to be written to the disk.
var buf bytes.Buffer
if err := serializeInvoice(&buf, i); err != nil {
return 0, nil
}
if err := invoices.Put(invoiceKey[:], buf.Bytes()); err != nil {
return 0, err
}
return nextAddSeqNo, nil
}
func serializeInvoice(w io.Writer, i *Invoice) error {
if err := wire.WriteVarBytes(w, 0, i.Memo[:]); err != nil {
return err
}
if err := wire.WriteVarBytes(w, 0, i.Receipt[:]); err != nil {
return err
}
if err := wire.WriteVarBytes(w, 0, i.PaymentRequest[:]); err != nil {
return err
}
birthBytes, err := i.CreationDate.MarshalBinary()
if err != nil {
return err
}
if err := wire.WriteVarBytes(w, 0, birthBytes); err != nil {
return err
}
settleBytes, err := i.SettleDate.MarshalBinary()
if err != nil {
return err
}
if err := wire.WriteVarBytes(w, 0, settleBytes); err != nil {
return err
}
if _, err := w.Write(i.Terms.PaymentPreimage[:]); err != nil {
return err
}
var scratch [8]byte
byteOrder.PutUint64(scratch[:], uint64(i.Terms.Value))
if _, err := w.Write(scratch[:]); err != nil {
return err
}
if err := binary.Write(w, byteOrder, i.Terms.Settled); err != nil {
return err
}
if err := binary.Write(w, byteOrder, i.AddIndex); err != nil {
return err
}
if err := binary.Write(w, byteOrder, i.SettleIndex); err != nil {
return err
}
if err := binary.Write(w, byteOrder, int64(i.AmtPaid)); err != nil {
return err
}
return nil
}
func fetchInvoice(invoiceNum []byte, invoices *bolt.Bucket) (Invoice, error) {
invoiceBytes := invoices.Get(invoiceNum)
if invoiceBytes == nil {
return Invoice{}, ErrInvoiceNotFound
}
invoiceReader := bytes.NewReader(invoiceBytes)
return deserializeInvoice(invoiceReader)
}
func deserializeInvoice(r io.Reader) (Invoice, error) {
var err error
invoice := Invoice{}
// TODO(roasbeef): use read full everywhere
invoice.Memo, err = wire.ReadVarBytes(r, 0, MaxMemoSize, "")
if err != nil {
return invoice, err
}
invoice.Receipt, err = wire.ReadVarBytes(r, 0, MaxReceiptSize, "")
if err != nil {
return invoice, err
}
invoice.PaymentRequest, err = wire.ReadVarBytes(r, 0, MaxPaymentRequestSize, "")
if err != nil {
return invoice, err
}
birthBytes, err := wire.ReadVarBytes(r, 0, 300, "birth")
if err != nil {
return invoice, err
}
if err := invoice.CreationDate.UnmarshalBinary(birthBytes); err != nil {
return invoice, err
}
settledBytes, err := wire.ReadVarBytes(r, 0, 300, "settled")
if err != nil {
return invoice, err
}
if err := invoice.SettleDate.UnmarshalBinary(settledBytes); err != nil {
return invoice, err
}
if _, err := io.ReadFull(r, invoice.Terms.PaymentPreimage[:]); err != nil {
return invoice, err
}
var scratch [8]byte
if _, err := io.ReadFull(r, scratch[:]); err != nil {
return invoice, err
}
invoice.Terms.Value = lnwire.MilliSatoshi(byteOrder.Uint64(scratch[:]))
if err := binary.Read(r, byteOrder, &invoice.Terms.Settled); err != nil {
return invoice, err
}
if err := binary.Read(r, byteOrder, &invoice.AddIndex); err != nil {
return invoice, err
}
if err := binary.Read(r, byteOrder, &invoice.SettleIndex); err != nil {
return invoice, err
}
if err := binary.Read(r, byteOrder, &invoice.AmtPaid); err != nil {
return invoice, err
}
return invoice, nil
}
func settleInvoice(invoices, settleIndex *bolt.Bucket, invoiceNum []byte,
amtPaid lnwire.MilliSatoshi) (*Invoice, error) {
invoice, err := fetchInvoice(invoiceNum, invoices)
if err != nil {
return nil, err
}
// Add idempotency to duplicate settles, return here to avoid
// overwriting the previous info.
if invoice.Terms.Settled {
return &invoice, nil
}
// Now that we know the invoice hasn't already been settled, we'll
// update the settle index so we can place this settle event in the
// proper location within our time series.
nextSettleSeqNo, err := settleIndex.NextSequence()
if err != nil {
return nil, err
}
var seqNoBytes [8]byte
byteOrder.PutUint64(seqNoBytes[:], nextSettleSeqNo)
if err := settleIndex.Put(seqNoBytes[:], invoiceNum); err != nil {
return nil, err
}
invoice.AmtPaid = amtPaid
invoice.Terms.Settled = true
invoice.SettleDate = time.Now()
invoice.SettleIndex = nextSettleSeqNo
var buf bytes.Buffer
if err := serializeInvoice(&buf, &invoice); err != nil {
return nil, err
}
if err := invoices.Put(invoiceNum[:], buf.Bytes()); err != nil {
return nil, err
}
return &invoice, nil
}