wip: diff diagnostic endpoint

internal/dataplane/kong_client.go

@@ -782,6 +782,7 @@ func (c *KongClient) sendToClient(
 	// apply the configuration update in Kong
 	timedCtx, cancel := context.WithTimeout(ctx, c.requestTimeout)
 	defer cancel()
+	// TRR this is the point in kongclient where db events maybe happen, but it's not differentiated by strategy here
 	newConfigSHA, err := sendconfig.PerformUpdate(
 		timedCtx,
 		logger,

internal/dataplane/sendconfig/dbmode.go

@@ -17,6 +17,7 @@ import (
 	"github.com/kong/go-kong/kong"
 
 	"github.com/kong/kubernetes-ingress-controller/v3/internal/dataplane/deckerrors"
+	"github.com/kong/kubernetes-ingress-controller/v3/internal/diagnostics"
 	"github.com/kong/kubernetes-ingress-controller/v3/internal/metrics"
 	"github.com/kong/kubernetes-ingress-controller/v3/internal/util"
 )
@@ -89,7 +90,11 @@ func (s UpdateStrategyDBMode) Update(ctx context.Context, targetContent ContentW
 	}
 
 	ctx, cancel := context.WithCancel(ctx)
-	go s.HandleEvents(ctx, syncer.GetResultChan())
+	// TRR this is where db mode update strat handles events. resultchan is the entityaction channel
+	// TRR targetContent.Hash is the config hash
+	// TRR TODO need to plumb the actual channel from the diag server over here. standin black hole for now
+	diffs := make(chan diagnostics.ConfigDiff, 3)
+	go s.HandleEvents(ctx, syncer.GetResultChan(), diffs, string(targetContent.Hash))
 
 	_, errs, _ := syncer.Solve(ctx, s.concurrency, false, false)
 	cancel()
@@ -115,10 +120,50 @@ func (s UpdateStrategyDBMode) Update(ctx context.Context, targetContent ContentW
 	return nil
 }
 
+// TRR upstream type
+//// EntityAction describes an entity processed by the diff engine and the action taken on it.
+//type EntityAction struct {
+//	// Action is the ReconcileAction taken on the entity.
+//	Action ReconcileAction `json:"action"` // string
+//	// Entity holds the processed entity.
+//	Entity Entity `json:"entity"`
+//	// Diff is diff string describing the modifications made to an entity.
+//	Diff string `json:"-"`
+//	// Error is the error encountered processing and entity, if any.
+//	Error error `json:"error,omitempty"`
+//}
+//
+//// Entity is an entity processed by the diff engine.
+//type Entity struct {
+//	// Name is the name of the entity.
+//	Name string `json:"name"`
+//	// Kind is the type of entity.
+//	Kind string `json:"kind"`
+//	// Old is the original entity in the current state, if any.
+//	Old any `json:"old,omitempty"`
+//	// New is the new entity in the target state, if any.
+//	New any `json:"new,omitempty"`
+//}
+
 // HandleEvents handles logging and error reporting for individual entity change events generated during a sync by
 // looping over an event channel. It terminates when its context dies.
-func (s *UpdateStrategyDBMode) HandleEvents(ctx context.Context, events chan diff.EntityAction) {
+func (s *UpdateStrategyDBMode) HandleEvents(
+	ctx context.Context,
+	events chan diff.EntityAction,
+	diffChan chan diagnostics.ConfigDiff,
+	hash string,
+) {
+	// TRR this is where we get the diff info from deck
 	s.resourceErrorLock.Lock()
+	// TRR TODO this accumulator isn't great since we need to append to the array, which is... probably unsafe? maybe
+	// the for can't actually handle multiple select inbounds at once, but I think it can, and append calls would cause
+	// havoc. can maybe use something from https://pkg.go.dev/sync/atomic to increment a counter, use that as a map key
+	// and then convert the values into a slice for the Done handler. otherwise this would need to send individual
+	// EntityDiffs down a channel to the diag server, which seems less than ideal
+	diff := diagnostics.ConfigDiff{
+		Hash:     hash,
+		Entities: []diagnostics.EntityDiff{},
+	}
 	for {
 		select {
 		case event := <-events:

internal/dataplane/sendconfig/sendconfig.go

@@ -71,6 +71,7 @@ func PerformUpdate(
 	updateStrategy := updateStrategyResolver.ResolveUpdateStrategy(client)
 	logger = logger.WithValues("update_strategy", updateStrategy.Type())
 	timeStart := time.Now()
+	// TRR this is the point in sendconfig where db events maybe happen, but it's not differentiated by strategy here
 	err = updateStrategy.Update(ctx, ContentWithHash{
 		Content: targetContent,
 		Hash:    newSHA,

internal/diagnostics/diff.go

@@ -0,0 +1,93 @@
+package diagnostics
+
+// TRR TODO this holds guts for diff endpoints. need to reorg the types.go into something that splits out the
+// subcomponents into separate files and move the base stuff into server.go probably.
+// the /config/{successful|failed} API endpoint structure isn't great for anything other than "current failure, last
+// succeeded" state (which is something we still care about). simplest option to handle the diffs within that landscape
+// is to have /config/{successful|failed}/diff, but that's a bit stuck on associating the correct one via the hashes.
+// we do now _have_ the hashes, but getting the config and diff separate and linking them together after in the
+// success/fail structure is maybe a bit wonky. a chronological sequence where the latest maybe has a failure attempt
+// attached is maybe simpler, but doesn't _quite_ solve the binding problem--would need to convert the hashes into
+// counters somehow
+
+// TRR upstream type
+//// EntityAction describes an entity processed by the diff engine and the action taken on it.
+//type EntityAction struct {
+//	// Action is the ReconcileAction taken on the entity.
+//	Action ReconcileAction `json:"action"` // string
+//	// Entity holds the processed entity.
+//	Entity Entity `json:"entity"`
+//	// Diff is diff string describing the modifications made to an entity.
+//	Diff string `json:"-"`
+//	// Error is the error encountered processing and entity, if any.
+//	Error error `json:"error,omitempty"`
+//}
+//
+//// Entity is an entity processed by the diff engine.
+//type Entity struct {
+//	// Name is the name of the entity.
+//	Name string `json:"name"`
+//	// Kind is the type of entity.
+//	Kind string `json:"kind"`
+//	// Old is the original entity in the current state, if any.
+//	Old any `json:"old,omitempty"`
+//	// New is the new entity in the target state, if any.
+//	New any `json:"new,omitempty"`
+//}
+
+type sourceResource struct {
+	Name             string
+	Namespace        string
+	GroupVersionKind string
+	UID              string
+}
+
+type generatedEntity struct {
+	// Name is the name of the entity.
+	Name string `json:"name"`
+	// Kind is the type of entity.
+	Kind string `json:"kind"`
+}
+
+type ConfigDiff struct {
+	Hash     string       `json:"hash"`
+	Entities []EntityDiff `json:"entities"`
+}
+
+type EntityDiff struct {
+	Source    sourceResource  `json:"kubernetesResource"`
+	Generated generatedEntity `json:"kongEntity"`
+	Action    string          `json:"action"`
+	Diff      string          `json:"diff,omitempty"`
+}
+
+// TRR TODO this is stolen from the error event builder, which parses regurgitated entity tags into k8s parents.
+// we want the same here, minus the additional error info. could probably make it a function in
+// internal/util/k8s.go along with sourceResource, but for now it's just sitting here for reference.
+// the end function probably won't keep the GVK entries separate? dunno--we want that for the event builder, but for
+// the diag server we just want to get the string version. can probably use the upstream GVK type in the generic
+// function and call its String().
+
+//func parseTags([]string) {
+//	for _, tag := range raw.Tags {
+//		if strings.HasPrefix(tag, util.K8sNameTagPrefix) {
+//			re.Name = strings.TrimPrefix(tag, util.K8sNameTagPrefix)
+//		}
+//		if strings.HasPrefix(tag, util.K8sNamespaceTagPrefix) {
+//			re.Namespace = strings.TrimPrefix(tag, util.K8sNamespaceTagPrefix)
+//		}
+//		if strings.HasPrefix(tag, util.K8sKindTagPrefix) {
+//			gvk.Kind = strings.TrimPrefix(tag, util.K8sKindTagPrefix)
+//		}
+//		if strings.HasPrefix(tag, util.K8sVersionTagPrefix) {
+//			gvk.Version = strings.TrimPrefix(tag, util.K8sVersionTagPrefix)
+//		}
+//		// this will not set anything for core resources
+//		if strings.HasPrefix(tag, util.K8sGroupTagPrefix) {
+//			gvk.Group = strings.TrimPrefix(tag, util.K8sGroupTagPrefix)
+//		}
+//		if strings.HasPrefix(tag, util.K8sUIDTagPrefix) {
+//			re.UID = strings.TrimPrefix(tag, util.K8sUIDTagPrefix)
+//		}
+//	}
+//}

internal/diagnostics/server.go

@@ -66,6 +66,7 @@ func NewServer(logger logr.Logger, cfg ServerConfig) Server {
 		s.configDumps = ConfigDumpDiagnostic{
 			DumpsIncludeSensitive: cfg.DumpSensitiveConfig,
 			Configs:               make(chan ConfigDump, diagnosticConfigBufferDepth),
+			Diffs:                 make(chan ConfigDiff, diagnosticConfigBufferDepth),
 		}
 	}
 

internal/diagnostics/types.go

@@ -44,6 +44,8 @@ type ConfigDumpDiagnostic struct {
 	DumpsIncludeSensitive bool
 	// Configs is the channel that receives configuration blobs from the configuration update strategy implementation.
 	Configs chan ConfigDump
+	// Diffs is the channel that receives diff info in DB mode.
+	Diffs chan ConfigDiff
 }
 
 // AffectedObject is a Kubernetes object associated with diagnostic information.