From 10222f98da0ff56ed247566b85509f72af5fd1a2 Mon Sep 17 00:00:00 2001
From: Max Altgelt <max.altgelt@nextron-systems.com>
Date: Tue, 19 Aug 2025 16:16:20 +0200
Subject: [PATCH] feat: skip specific values in context

---
 textlog.go             | 49 ++++++++++++++++++++++++------------------
 thorlog/v3/event.go    | 13 +++++++++++
 thorlog/v3/registry.go |  4 ++--
 3 files changed, 43 insertions(+), 23 deletions(-)

diff --git a/textlog.go b/textlog.go
index 3024c65..cc22125 100644
--- a/textlog.go
+++ b/textlog.go
@@ -30,6 +30,9 @@ type TextlogValuePair struct {
 type TextlogFormatter struct {
 	// FormatValue is a function that formats a single value into a string. If it is nil, fmt.Sprint is used.
 	FormatValue func(data any, modifiers []string) string
+	// Omit is a function that determines whether a field should be omitted from the log entry.
+	// If it is nil, no fields are omitted.
+	Omit func(modifiers []string, value any) bool
 }
 
 func (t TextlogFormatter) format(data any, modifiers []string) string {
@@ -114,30 +117,34 @@ func (t TextlogFormatter) toEntry(object reflect.Value) TextlogEntry {
 			if logfield == "-" {
 				continue
 			}
-			if typeField.Anonymous || textlogTag != "" || slices.Contains(tagModifiers, modifierExplicit) {
-				if slices.Contains(tagModifiers, modifierOmitempty) && isZero(field) {
-					continue
-				}
-				if typeField.Anonymous || slices.Contains(tagModifiers, modifierExpand) {
-					// Use the tag as a prefix for the subfields
-					subentry := t.toEntry(field)
-					for _, subentryValue := range subentry {
-						details = append(details, TextlogValuePair{
-							Key:   ConcatTextLabels(logfield, subentryValue.Key),
-							Value: subentryValue.Value,
-						})
-					}
-				} else {
-					// Add the field as a single value
-					key := logfield
-					if field.Kind() == reflect.Ptr {
-						field = field.Elem()
-					}
+			if !typeField.Anonymous && textlogTag == "" && !slices.Contains(tagModifiers, modifierExplicit) {
+				continue
+			}
+			if slices.Contains(tagModifiers, modifierOmitempty) && isZero(field) {
+				continue
+			}
+			if t.Omit != nil && t.Omit(tagModifiers, field.Interface()) {
+				continue
+			}
+			if typeField.Anonymous || slices.Contains(tagModifiers, modifierExpand) {
+				// Use the tag as a prefix for the subfields
+				subentry := t.toEntry(field)
+				for _, subentryValue := range subentry {
 					details = append(details, TextlogValuePair{
-						Key:   key,
-						Value: t.format(field.Interface(), tagModifiers),
+						Key:   ConcatTextLabels(logfield, subentryValue.Key),
+						Value: subentryValue.Value,
 					})
 				}
+			} else {
+				// Add the field as a single value
+				key := logfield
+				if field.Kind() == reflect.Ptr {
+					field = field.Elem()
+				}
+				details = append(details, TextlogValuePair{
+					Key:   key,
+					Value: t.format(field.Interface(), tagModifiers),
+				})
 			}
 		}
 		return details
diff --git a/thorlog/v3/event.go b/thorlog/v3/event.go
index 314457c..e0eaa7d 100644
--- a/thorlog/v3/event.go
+++ b/thorlog/v3/event.go
@@ -11,6 +11,7 @@ import (
 	"github.com/NextronSystems/jsonlog"
 	"github.com/NextronSystems/jsonlog/jsonpointer"
 	"github.com/NextronSystems/jsonlog/thorlog/common"
+	"golang.org/x/exp/slices"
 )
 
 type Finding struct {
@@ -116,6 +117,8 @@ func (c *ContextObject) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
+const omitInContext = "omitincontext"
+
 func (c Context) MarshalTextLog(t jsonlog.TextlogFormatter) jsonlog.TextlogEntry {
 	var elementsByRelation [][]ContextObject
 	for _, element := range c {
@@ -131,6 +134,16 @@ func (c Context) MarshalTextLog(t jsonlog.TextlogFormatter) jsonlog.TextlogEntry
 			elementsByRelation = append(elementsByRelation, []ContextObject{element})
 		}
 	}
+	oldOmit := t.Omit
+	t.Omit = func(modifiers []string, value any) bool {
+		if slices.Contains(modifiers, omitInContext) {
+			return true // Omit fields that are marked with "omitincontext"
+		}
+		if oldOmit != nil {
+			return oldOmit(modifiers, value) // Call the original omit function if it exists
+		}
+		return false // Default behavior is to not omit any fields
+	}
 
 	var result jsonlog.TextlogEntry
 	for _, group := range elementsByRelation {
diff --git a/thorlog/v3/registry.go b/thorlog/v3/registry.go
index 8eefc1f..55297a5 100644
--- a/thorlog/v3/registry.go
+++ b/thorlog/v3/registry.go
@@ -11,7 +11,7 @@ type RegistryValue struct {
 
 	Key         string    `json:"key" textlog:"key"`
 	Modified    time.Time `json:"modified" textlog:"modified"`
-	ParsedValue string    `json:"value" textlog:"value"`
+	ParsedValue string    `json:"value" textlog:"value,omitincontext"`
 	Size        uint64    `json:"size" textlog:"size"`
 }
 
@@ -33,7 +33,7 @@ type RegistryKey struct {
 	jsonlog.ObjectHeader
 	Key             string    `json:"key" textlog:"key"`
 	Modified        time.Time `json:"modified" textlog:"modified"`
-	FormattedValues string    `json:"values" textlog:"values"`
+	FormattedValues string    `json:"values" textlog:"values,omitincontext"`
 }
 
 func (RegistryKey) reportable() {}