/
change_log.go
381 lines (356 loc) · 10.5 KB
/
change_log.go
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package proxy
import (
"fmt"
"time"
"errors"
"github.com/dgate-io/dgate/pkg/spec"
"github.com/dgate-io/dgate/pkg/util/sliceutil"
"github.com/dgraph-io/badger/v4"
"github.com/mitchellh/mapstructure"
"github.com/rs/zerolog"
)
// processChangeLog - processes a change log and applies the change to the proxy state
func (ps *ProxyState) processChangeLog(
cl *spec.ChangeLog, apply, store bool,
) (err error) {
// TODO: add revert cl function to check if storage fails or something
if !cl.Cmd.IsNoop() {
switch cl.Cmd.Resource() {
case spec.Namespaces:
var item spec.Namespace
item, err = decode[spec.Namespace](cl.Item)
if err == nil {
ps.logger.Trace().Msgf("Processing namespace: %s", item.Name)
err = ps.processNamespace(&item, cl)
}
case spec.Services:
var item spec.Service
item, err = decode[spec.Service](cl.Item)
if err == nil {
ps.logger.Trace().Msgf("Processing service: %s", item.Name)
err = ps.processService(&item, cl)
}
case spec.Routes:
var item spec.Route
item, err = decode[spec.Route](cl.Item)
if err == nil {
ps.logger.Trace().Msgf("Processing route: %s", item.Name)
err = ps.processRoute(&item, cl)
}
case spec.Modules:
var item spec.Module
item, err = decode[spec.Module](cl.Item)
if err == nil {
ps.logger.Trace().Msgf("Processing module: %s", item.Name)
err = ps.processModule(&item, cl)
}
case spec.Domains:
var item spec.Domain
item, err = decode[spec.Domain](cl.Item)
if err == nil {
ps.logger.Trace().Msgf("Processing domain: %s", item.Name)
err = ps.processDomain(&item, cl)
}
case spec.Collections:
var item spec.Collection
item, err = decode[spec.Collection](cl.Item)
if err == nil {
ps.logger.Trace().Msgf("Processing domain: %s", item.Name)
err = ps.processCollection(&item, cl)
}
case spec.Documents:
var item spec.Document
item, err = decode[spec.Document](cl.Item)
if err == nil {
ps.logger.Trace().Msgf("Processing domain: %s", item.ID)
err = ps.processDocument(&item, cl)
}
default:
err = fmt.Errorf("unknown command: %s", cl.Cmd)
}
if err != nil {
ps.logger.Err(err).Msg("error processing change log")
return
}
}
if apply && (cl.Cmd.Resource().IsRelatedTo(spec.Routes) || cl.Cmd.IsNoop()) {
ps.logger.Trace().Msgf("Registering change log: %s", cl.Cmd)
errChan := ps.applyChange(cl)
select {
case err = <-errChan:
break
case <-time.After(time.Second * 15):
err = errors.New("timeout applying change log")
}
if err != nil {
ps.logger.Err(err).Msg("Error registering change log")
return
}
}
if store {
err = ps.store.StoreChangeLog(cl)
if err != nil {
// TODO: Add config option to panic on persistent storage errors
// TODO: maybe revert change here or add to some in-memory queue for changes?
ps.logger.Err(err).Msg("Error storing change log")
return
}
}
changeHash, err := HashAny[*spec.ChangeLog](ps.changeHash, cl)
if err != nil {
if !ps.config.Debug {
return err
}
ps.logger.Error().Err(err).
Msg("error updating change log hash")
} else {
ps.changeHash = changeHash
}
return nil
}
func decode[T any](input any) (T, error) {
var output T
cfg := &mapstructure.DecoderConfig{
Metadata: nil,
Result: &output,
TagName: "json",
DecodeHook: mapstructure.ComposeDecodeHookFunc(
mapstructure.StringToTimeHookFunc(time.RFC3339),
mapstructure.StringToTimeDurationHookFunc(),
),
}
if dec, err := mapstructure.NewDecoder(cfg); err != nil {
return output, err
} else if err = dec.Decode(input); err != nil {
return output, err
}
return output, nil
}
func (ps *ProxyState) processNamespace(ns *spec.Namespace, cl *spec.ChangeLog) error {
switch cl.Cmd.Action() {
case spec.Add:
ps.rm.AddNamespace(ns)
return nil
case spec.Delete:
return ps.rm.RemoveNamespace(ns.Name)
default:
return fmt.Errorf("unknown command: %s", cl.Cmd)
}
}
func (ps *ProxyState) processService(svc *spec.Service, cl *spec.ChangeLog) (err error) {
if svc.NamespaceName == "" {
svc.NamespaceName = cl.Namespace
}
switch cl.Cmd.Action() {
case spec.Add:
_, err = ps.rm.AddService(svc)
case spec.Delete:
_, err = ps.rm.AddService(svc)
default:
err = fmt.Errorf("unknown command: %s", cl.Cmd)
}
return err
}
func (ps *ProxyState) processRoute(rt *spec.Route, cl *spec.ChangeLog) (err error) {
if rt.NamespaceName == "" {
rt.NamespaceName = cl.Namespace
}
switch cl.Cmd.Action() {
case spec.Add:
_, err = ps.rm.AddRoute(rt)
case spec.Delete:
_, err = ps.rm.AddRoute(rt)
default:
err = fmt.Errorf("unknown command: %s", cl.Cmd)
}
return err
}
func (ps *ProxyState) processModule(mod *spec.Module, cl *spec.ChangeLog) (err error) {
if mod.NamespaceName == "" {
mod.NamespaceName = cl.Namespace
}
switch cl.Cmd.Action() {
case spec.Add:
_, err = ps.rm.AddModule(mod)
case spec.Delete:
_, err = ps.rm.AddModule(mod)
default:
err = fmt.Errorf("unknown command: %s", cl.Cmd)
}
return err
}
func (ps *ProxyState) processDomain(dom *spec.Domain, cl *spec.ChangeLog) (err error) {
if dom.NamespaceName == "" {
dom.NamespaceName = cl.Namespace
}
switch cl.Cmd.Action() {
case spec.Add:
_, err = ps.rm.AddDomain(dom)
case spec.Delete:
_, err = ps.rm.AddDomain(dom)
default:
err = fmt.Errorf("unknown command: %s", cl.Cmd)
}
return err
}
func (ps *ProxyState) processCollection(col *spec.Collection, cl *spec.ChangeLog) (err error) {
if col.NamespaceName == "" {
col.NamespaceName = cl.Namespace
}
switch cl.Cmd.Action() {
case spec.Add:
_, err = ps.rm.AddCollection(col)
case spec.Delete:
_, err = ps.rm.AddCollection(col)
default:
err = fmt.Errorf("unknown command: %s", cl.Cmd)
}
return err
}
func (ps *ProxyState) processDocument(doc *spec.Document, cl *spec.ChangeLog) (err error) {
if doc.NamespaceName == "" {
doc.NamespaceName = cl.Namespace
}
switch cl.Cmd.Action() {
case spec.Add:
err = ps.store.StoreDocument(doc)
case spec.Delete:
err = ps.store.DeleteDocument(doc)
default:
err = fmt.Errorf("unknown command: %s", cl.Cmd)
}
return err
}
// applyChange - apply a change to the proxy state, returns a channel that will receive an error when the state has been updated
func (ps *ProxyState) applyChange(changeLog *spec.ChangeLog) <-chan error {
done := make(chan error, 1)
if changeLog == nil {
changeLog = &spec.ChangeLog{
Cmd: spec.NoopCommand,
}
}
changeLog.SetErrorChan(done)
ps.changeChan <- changeLog
return done
}
func (ps *ProxyState) rollbackChange(changeLog *spec.ChangeLog) {
if changeLog == nil {
return
}
ps.changeChan <- changeLog
}
func (ps *ProxyState) restoreFromChangeLogs() error {
// restore state change logs
logs, err := ps.store.FetchChangeLogs()
if err != nil {
if err == badger.ErrKeyNotFound {
ps.logger.Debug().Msg("no state change logs found in storage")
} else {
return errors.New("failed to get state change logs from storage: " + err.Error())
}
} else {
ps.logger.Info().Msg(fmt.Sprintf("restoring %d state change logs from storage", len(logs)))
// we might need to sort the change logs by timestamp
for i, cl := range logs {
ps.logger.Trace().
Interface("changeLog: "+cl.Name, cl).Msgf("restoring change log index: %d", i)
lastIteration := i == len(logs)-1
err = ps.processChangeLog(cl, lastIteration, false)
if err != nil {
return err
}
}
// TODO: change to configurable variable
if len(logs) > 1 {
removed, err := ps.compactChangeLogs(logs)
if err != nil {
ps.logger.Error().Err(err).Msg("failed to compact state change logs")
return err
}
if removed > 0 {
ps.logger.Info().Msgf("compacted change logs by removing %d out of %d logs", removed, len(logs))
}
}
}
return nil
}
func (ps *ProxyState) compactChangeLogs(logs []*spec.ChangeLog) (int, error) {
removeList := compactChangeLogsRemoveList(&ps.logger, sliceutil.SliceCopy(logs))
removed, err := ps.store.DeleteChangeLogs(removeList)
if err != nil {
return removed, err
}
return removed, nil
}
/*
compactChangeLogsRemoveList - compacts a list of change logs by removing redundant logs
TODO: perhaps add flag for compacting change logs on startup (mark as experimental)
compaction rules:
- if an add command is followed by a delete command with matching keys, remove both commands
- if an add command is followed by another add command with matching keys, remove the first add command
*/
func compactChangeLogsRemoveList(logger *zerolog.Logger, logs []*spec.ChangeLog) []*spec.ChangeLog {
removeList := make([]*spec.ChangeLog, 0)
iterations := 0
START:
var prevLog *spec.ChangeLog
// TODO: this can be extended by separating the logs into namespace groups and then compacting each group
for i := 0; i < len(logs); i++ {
iterations++
curLog := logs[i]
if prevLog != nil {
if prevLog.Cmd.IsNoop() {
removeList = append(removeList, prevLog)
logs = append(logs[:i-1], logs[i:]...)
goto START
}
commonResource := prevLog.Cmd.Resource() == curLog.Cmd.Resource()
if prevLog.Cmd.Action() == spec.Add && curLog.Cmd.Action() == spec.Delete && commonResource {
// Rule 1: if an add command is followed by a delete command with matching keys, remove both commands
if prevLog.Name == curLog.Name && prevLog.Namespace == curLog.Namespace {
removeList = append(removeList, prevLog, curLog)
logs = append(logs[:i-1], logs[i+1:]...)
goto START
}
}
commonAction := prevLog.Cmd.Action() == curLog.Cmd.Action()
if prevLog.Cmd.Action() == spec.Add && commonAction && commonResource {
// Rule 2: if an add command is followed by another add command with matching keys, remove the first add command
if prevLog.Name == curLog.Name && prevLog.Namespace == curLog.Namespace {
removeList = append(removeList, prevLog)
logs = append(logs[:i-1], logs[i:]...)
goto START
}
}
}
prevLog = curLog
}
if logger != nil {
logger.Debug().Msgf("compacted change logs in %d iterations", iterations)
}
// remove duplicates from list
removeList = sliceutil.SliceUnique(removeList, func(cl *spec.ChangeLog) string { return cl.ID })
return removeList
}
// Function to check if there is a delete command between two logs with matching keys
// func hasDeleteBetween(logs []*spec.ChangeLog, start, end *spec.ChangeLog) bool {
// startIndex := -1
// endIndex := -1
// for i, log := range logs {
// if log.ID == start.ID {
// startIndex = i
// }
// if log.ID == end.ID {
// endIndex = i
// }
// }
// if startIndex == -1 || endIndex == -1 {
// return false
// }
// for i := startIndex + 1; i < endIndex; i++ {
// if logs[i].Cmd.IsDeleteCommand() {
// return true
// }
// }
// return false
// }