From 433fc57882dab892b4c06addfd4f6b9c8656dd61 Mon Sep 17 00:00:00 2001
From: Konstanty Karagiorgis <konstanty.karagiorgis@gmail.com>
Date: Wed, 4 Dec 2024 23:44:33 +0100
Subject: [PATCH] #85 Long service names are now truncated

---
 pkg/k8s/exposer.go      | 34 ++++++++++++++++++++++++++++++++--
 pkg/k8s/exposer_test.go | 12 ++++++++++++
 pkg/k8s/services.go     |  8 +++++---
 3 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/pkg/k8s/exposer.go b/pkg/k8s/exposer.go
index 4ff04db..fc705c3 100644
--- a/pkg/k8s/exposer.go
+++ b/pkg/k8s/exposer.go
@@ -2,6 +2,8 @@
 package k8s
 
 import (
+	"crypto/sha256"
+	"encoding/hex"
 	"fmt"
 	"strconv"
 	"strings"
@@ -46,7 +48,7 @@ func (exp *k8sResourceExposer) Add(app apps.App) (apps.App, error) {
 	if childFactoryErr != nil {
 		return apps.App{}, childFactoryErr
 	}
-	entityName := fmt.Sprintf("%s-%s", app.Peer, app.Name)
+	entityName := capName(fmt.Sprintf("%s-%s", app.Peer, app.Name))
 	for _, managedResource := range exp.managedResources {
 		addErr := managedResource.Add(k8sResourceMetadata{
 			entityName:      entityName,
@@ -65,7 +67,7 @@ func (exp *k8sResourceExposer) Withdraw(app apps.App) error {
 	if clientSetErr != nil {
 		return clientSetErr
 	}
-	entityName := fmt.Sprintf("%s-%s", app.Peer, app.Name)
+	entityName := capName(fmt.Sprintf("%s-%s", app.Peer, app.Name))
 	for i := range exp.managedResources {
 		managedResource := exp.managedResources[len(exp.managedResources)-1-i]
 		removeErr := managedResource.Remove(entityName, clientset)
@@ -129,3 +131,31 @@ func extractPortFromAddr(address string) (int, error) {
 	parts := strings.Split(address, ":")
 	return strconv.Atoi(parts[1])
 }
+
+func capName(name string) string {
+	if len(name) <= 63 {
+		return name
+	}
+
+	// Calculate hash of the full name
+	hasher := sha256.New()
+	hasher.Write([]byte(name))
+	hash := hex.EncodeToString(hasher.Sum(nil))[:8] // Take first 8 chars of hash
+
+	// We need 9 chars for "-" + hash
+	// So we can search up to position 54 (63 - 9 = 54)
+	searchStart := 32
+	searchEnd := 54
+
+	substring := name[searchStart:searchEnd]
+	hyphenIndex := strings.LastIndex(substring, "-")
+
+	if hyphenIndex != -1 {
+		// Found hyphen in the search range
+		actualIndex := searchStart + hyphenIndex
+		return name[:actualIndex] + "-" + hash
+	}
+
+	// No suitable hyphen found, cut at position 54
+	return name[:54] + "-" + hash
+}
diff --git a/pkg/k8s/exposer_test.go b/pkg/k8s/exposer_test.go
index a017c5e..e9141cd 100644
--- a/pkg/k8s/exposer_test.go
+++ b/pkg/k8s/exposer_test.go
@@ -149,3 +149,15 @@ func TestExposerWithdrawAll(t *testing.T) {
 	assert.Equal(t, 0, rsc2.removeAllCalled)
 	assert.Equal(t, 1, rsc1.removeAllCalled)
 }
+
+func TestCapName(t *testing.T) {
+	assert.Equal(t, "", capName(""))
+	assert.Equal(t, "foo-bar-baz", capName("foo-bar-baz"))
+	assert.Equal(
+		t,
+		"alpha-beta-gamma-delta-epsilon-zeta-eta-iota-kappa-76198ab9",
+		capName(
+			"alpha-beta-gamma-delta-epsilon-zeta-eta-iota-kappa-lambda-mi-ni-xi-omikron-pi-rho-sigma",
+		),
+	)
+}
diff --git a/pkg/k8s/services.go b/pkg/k8s/services.go
index 7eab548..012870f 100644
--- a/pkg/k8s/services.go
+++ b/pkg/k8s/services.go
@@ -58,11 +58,13 @@ func (m *managedK8sService) Add(metadata k8sResourceMetadata, clientset *kuberne
 
 func (m *managedK8sService) Remove(entityName string, clientset *kubernetes.Clientset) error {
 	servicesClient := clientset.CoreV1().Services(m.namespace)
-	deleteErr := servicesClient.Delete(context.Background(), entityName, metav1.DeleteOptions{})
+	deleteErr := servicesClient.Delete(context.Background(), capName(
+		entityName,
+	), metav1.DeleteOptions{})
 	if deleteErr != nil {
-		return fmt.Errorf("Could not delete service %s: %v", entityName, deleteErr)
+		return fmt.Errorf("Could not delete service %s: %v", capName(entityName), deleteErr)
 	}
-	logrus.Infof("Deleted service %s", entityName)
+	logrus.Infof("Deleted service %s", capName(entityName))
 	return nil
 }