zitadel/internal/eventstore/read_model.go
Silvan b522588d98
fix(eventstore): precise decimal (#8527)
# Which Problems Are Solved

Float64 which was used for the event.Position field is [not precise in
go and gets rounded](https://github.com/golang/go/issues/47300). This
can lead to unprecies position tracking of events and therefore
projections especially on cockcoachdb as the position used there is a
big number.

example of a unprecies position:
exact: 1725257931223002628
float64: 1725257931223002624.000000

# How the Problems Are Solved

The float64 was replaced by
[github.com/jackc/pgx-shopspring-decimal](https://github.com/jackc/pgx-shopspring-decimal).

# Additional Changes

Correct behaviour of makefile for load tests.
Rename `latestSequence`-queries to `latestPosition`
2024-09-06 12:19:19 +03:00

56 lines
1.6 KiB
Go

package eventstore
import (
"time"
"github.com/shopspring/decimal"
)
// ReadModel is the minimum representation of a read model.
// It implements a basic reducer
// it might be saved in a database or in memory
type ReadModel struct {
AggregateID string `json:"-"`
ProcessedSequence uint64 `json:"-"`
CreationDate time.Time `json:"-"`
ChangeDate time.Time `json:"-"`
Events []Event `json:"-"`
ResourceOwner string `json:"-"`
InstanceID string `json:"-"`
Position decimal.Decimal `json:"-"`
}
// AppendEvents adds all the events to the read model.
// The function doesn't compute the new state of the read model
func (rm *ReadModel) AppendEvents(events ...Event) {
rm.Events = append(rm.Events, events...)
}
// Reduce is the basic implementation of reducer
// If this function is extended the extending function should be the last step
func (rm *ReadModel) Reduce() error {
if len(rm.Events) == 0 {
return nil
}
if rm.AggregateID == "" {
rm.AggregateID = rm.Events[0].Aggregate().ID
}
if rm.ResourceOwner == "" {
rm.ResourceOwner = rm.Events[0].Aggregate().ResourceOwner
}
if rm.InstanceID == "" {
rm.InstanceID = rm.Events[0].Aggregate().InstanceID
}
if rm.CreationDate.IsZero() {
rm.CreationDate = rm.Events[0].CreatedAt()
}
rm.ChangeDate = rm.Events[len(rm.Events)-1].CreatedAt()
rm.ProcessedSequence = rm.Events[len(rm.Events)-1].Sequence()
rm.Position = rm.Events[len(rm.Events)-1].Position()
// all events processed and not needed anymore
rm.Events = rm.Events[0:0]
return nil
}