fix: regenerate vector config on app lifecycle changes

The generated vector config is a snapshot of the app list and their sink properties, but it was only ever written by `logs:set` and `logs:vector-start`. Renaming an app left a source filtering on a label no container carries and gave the new name no source at all, so the app kept a sink with nothing feeding it. Cloning produced the same result for the clone, and destroying an app left its source and sink behind, the latter still pointing at an endpoint decommissioned along with the app. The global relabel transform embeds app names directly in generated VRL, so a rename also left behind a branch naming an app that no longer existed. Every case was silent, and the only repair was an operator running `logs:vector-start`. The `post-app-clone-setup`, `post-app-rename-setup` and `post-delete` triggers now rewrite the config, warning rather than failing so that a config write cannot abort the app operation whose state it is derived from.

Closes #8918.

plugins/logs/functions.go

@@ -538,6 +538,17 @@ func vectorScopes() []vectorAppSinks {
 	})
 }
 
+// regenerateVectorConfig rewrites the generated vector config so that it matches
+// the current set of apps and their properties. App lifecycle triggers call this
+// instead of writeVectorConfig because the config is derived state: failing to
+// rewrite it should not abort the app operation that changed the state it is
+// derived from.
+func regenerateVectorConfig() {
+	if err := writeVectorConfig(); err != nil {
+		common.LogWarn(fmt.Sprintf("Unable to write updated vector config: %s", err.Error()))
+	}
+}
+
 func writeVectorConfig() error {
 	data, err := buildVectorConfig(vectorScopes())
 	if err != nil {

plugins/logs/functions_test.go

@@ -2,6 +2,7 @@ package logs
 
 import (
 	"encoding/json"
+	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -291,6 +292,10 @@ func setupScopesTest(t *testing.T, apps []string) {
 		t.Fatalf("PropertySetup: %v", err)
 	}
 
+	if err := common.CreateDataDirectory("logs"); err != nil {
+		t.Fatalf("CreateDataDirectory: %v", err)
+	}
+
 	for _, appName := range apps {
 		if err := os.MkdirAll(filepath.Join(os.Getenv("DOKKU_ROOT"), appName), 0755); err != nil {
 			t.Fatalf("MkdirAll %s: %v", appName, err)
@@ -298,6 +303,141 @@ func setupScopesTest(t *testing.T, apps []string) {
 	}
 }
 
+// setLogsProperty sets a logs property for the given scope and regenerates the
+// config, standing in for the logs:set command
+func setLogsProperty(t *testing.T, appName string, property string, value string) {
+	t.Helper()
+
+	if err := common.PropertyWrite("logs", appName, property, value); err != nil {
+		t.Fatalf("PropertyWrite %s %s: %v", appName, property, err)
+	}
+
+	if err := writeVectorConfig(); err != nil {
+		t.Fatalf("writeVectorConfig: %v", err)
+	}
+}
+
+// readVectorConfig decodes the generated config from disk
+func readVectorConfig(t *testing.T) map[string]interface{} {
+	t.Helper()
+
+	b, err := os.ReadFile(filepath.Join(common.GetDataDirectory("logs"), "vector.json"))
+	if err != nil {
+		t.Fatalf("ReadFile vector.json: %v", err)
+	}
+
+	var decoded map[string]interface{}
+	if err := json.Unmarshal(b, &decoded); err != nil {
+		t.Fatalf("Unmarshal vector.json: %v", err)
+	}
+
+	return decoded
+}
+
+// assertComponents checks whether an app has a source and a sink in the config
+func assertComponents(t *testing.T, decoded map[string]interface{}, appName string, want bool) {
+	t.Helper()
+
+	components := map[string]string{
+		"sources": fmt.Sprintf("docker-source:%s", appName),
+		"sinks":   fmt.Sprintf("docker-sink:%s", appName),
+	}
+
+	for section, id := range components {
+		group, ok := lookup(t, decoded, section).(map[string]interface{})
+		if !ok {
+			t.Fatalf("%s is not a map", section)
+		}
+
+		if _, ok := group[id]; ok != want {
+			t.Errorf("%s[%q] exists = %v, want %v", section, id, ok, want)
+		}
+	}
+}
+
+// TestTriggerPostDeleteRewritesVectorConfig covers a destroyed app leaving its
+// source and sink behind forever. post-delete fires before the app root is
+// removed, so the app is still listed by UnfilteredDokkuApps at this point and
+// only drops out because its properties are destroyed first.
+func TestTriggerPostDeleteRewritesVectorConfig(t *testing.T) {
+	setupScopesTest(t, []string{"appa", "appb"})
+	setLogsProperty(t, "appa", "vector-sink", "console://?encoding[codec]=json")
+	setLogsProperty(t, "appb", "vector-sink", "console://?encoding[codec]=json")
+
+	assertComponents(t, readVectorConfig(t), "appa", true)
+
+	if err := TriggerPostDelete("appa"); err != nil {
+		t.Fatalf("TriggerPostDelete: %v", err)
+	}
+
+	decoded := readVectorConfig(t)
+	assertComponents(t, decoded, "appa", false)
+	assertComponents(t, decoded, "appb", true)
+}
+
+// TestTriggerPostAppRenameSetupRewritesVectorConfig covers the rename case: the
+// sink property follows the app, so without a regeneration the surviving source
+// filters on a label no container carries and the new name has no source at all.
+func TestTriggerPostAppRenameSetupRewritesVectorConfig(t *testing.T) {
+	setupScopesTest(t, []string{"appa", "appa-renamed"})
+	setLogsProperty(t, "appa", "vector-sink", "console://?encoding[codec]=json")
+
+	if err := TriggerPostAppRenameSetup("appa", "appa-renamed"); err != nil {
+		t.Fatalf("TriggerPostAppRenameSetup: %v", err)
+	}
+
+	decoded := readVectorConfig(t)
+	assertComponents(t, decoded, "appa", false)
+	assertComponents(t, decoded, "appa-renamed", true)
+
+	labels := lookup(t, decoded, "sources", "docker-source:appa-renamed", "include_labels")
+	if got := labels.([]interface{})[0]; got != "com.dokku.app-name=appa-renamed" {
+		t.Errorf("include_labels[0] = %v, want com.dokku.app-name=appa-renamed", got)
+	}
+}
+
+// TestTriggerPostAppCloneSetupRewritesVectorConfig covers the clone case, where
+// the clone inherits a sink but would otherwise have no source feeding it.
+func TestTriggerPostAppCloneSetupRewritesVectorConfig(t *testing.T) {
+	setupScopesTest(t, []string{"appa", "appa-clone"})
+	setLogsProperty(t, "appa", "vector-sink", "console://?encoding[codec]=json")
+
+	if err := TriggerPostAppCloneSetup("appa", "appa-clone"); err != nil {
+		t.Fatalf("TriggerPostAppCloneSetup: %v", err)
+	}
+
+	decoded := readVectorConfig(t)
+	assertComponents(t, decoded, "appa", true)
+	assertComponents(t, decoded, "appa-clone", true)
+}
+
+// TestTriggerPostAppRenameSetupRewritesGlobalRelabel pins the generated VRL,
+// which embeds app names directly as branches of the global relabel transform.
+// A rename leaves a branch naming an app that no longer exists, so the renamed
+// app ships under the global alias rather than its own.
+func TestTriggerPostAppRenameSetupRewritesGlobalRelabel(t *testing.T) {
+	setupScopesTest(t, []string{"appa", "appa-renamed"})
+	setLogsProperty(t, "--global", "vector-sink", "console://?encoding[codec]=json")
+	setLogsProperty(t, "appa", "app-label-alias", "app_name")
+
+	source := lookup(t, readVectorConfig(t), "transforms", "docker-global-relabel", "source").(string)
+	if !strings.Contains(source, `app == "appa"`) {
+		t.Fatalf("relabel source %q missing the pre-rename branch", source)
+	}
+
+	if err := TriggerPostAppRenameSetup("appa", "appa-renamed"); err != nil {
+		t.Fatalf("TriggerPostAppRenameSetup: %v", err)
+	}
+
+	source = lookup(t, readVectorConfig(t), "transforms", "docker-global-relabel", "source").(string)
+	if strings.Contains(source, `app == "appa"`) {
+		t.Errorf("relabel source %q still names the old app", source)
+	}
+	if !strings.Contains(source, `app == "appa-renamed"`) {
+		t.Errorf("relabel source %q missing the renamed app", source)
+	}
+}
+
 func scopeByID(t *testing.T, scopes []vectorAppSinks, sourceID string) vectorAppSinks {
 	t.Helper()
 

plugins/logs/triggers.go

@@ -106,14 +106,20 @@ func TriggerLogsGetProperty(appName string, key string) error {
 	return nil
 }
 
-// TriggerPostAppCloneSetup creates new logs files
+// TriggerPostAppCloneSetup creates new logs files and regenerates the vector
+// config so that the clone gets a source of its own for the sink it inherited
 func TriggerPostAppCloneSetup(oldAppName string, newAppName string) error {
 	err := common.PropertyClone("logs", oldAppName, newAppName)
 	if err != nil {
 		return err
 	}
 
-	return common.CloneAppData("logs", oldAppName, newAppName)
+	if err := common.CloneAppData("logs", oldAppName, newAppName); err != nil {
+		return err
+	}
+
+	regenerateVectorConfig()
+	return nil
 }
 
 // TriggerPostAppRename removes the old app data
@@ -121,7 +127,9 @@ func TriggerPostAppRename(oldAppName string, newAppName string) error {
 	return common.MigrateAppDataDirectory("logs", oldAppName, newAppName)
 }
 
-// TriggerPostAppRenameSetup renames logs files
+// TriggerPostAppRenameSetup renames logs files and regenerates the vector config.
+// Both app roots exist at this point, but the old app no longer has any logs
+// properties, so it drops out of the generated config.
 func TriggerPostAppRenameSetup(oldAppName string, newAppName string) error {
 	if err := common.PropertyClone("logs", oldAppName, newAppName); err != nil {
 		return err
@@ -131,7 +139,12 @@ func TriggerPostAppRenameSetup(oldAppName string, newAppName string) error {
 		return err
 	}
 
-	return common.CloneAppData("logs", oldAppName, newAppName)
+	if err := common.CloneAppData("logs", oldAppName, newAppName); err != nil {
+		return err
+	}
+
+	regenerateVectorConfig()
+	return nil
 }
 
 // TriggerPostCreate ensures apps have the correct data directory structure
@@ -139,11 +152,16 @@ func TriggerPostCreate(appName string) error {
 	return common.CreateAppDataDirectory("logs", appName)
 }
 
-// TriggerPostDelete destroys the logs property for a given app container
+// TriggerPostDelete destroys the logs property for a given app container and
+// regenerates the vector config. The regeneration runs after the properties are
+// destroyed so that the app drops out of the config even though its app root is
+// only removed later in the destroy flow.
 func TriggerPostDelete(appName string) error {
 	dataErr := common.RemoveAppDataDirectory("logs", appName)
 	propertyErr := common.PropertyDestroy("logs", appName)
 
+	regenerateVectorConfig()
+
 	if dataErr != nil {
 		return dataErr
 	}