perf: reuse singleton ObjectMapper for Redis pub/sub serialization

Constructing a new ObjectMapper on every publish is expensive and was on
the websocket and batch-job hot paths. Inject the shared singleton instead,
matching how RedisPubSubReceiver already consumes it.

Author: bdshadow

backend/api/src/main/kotlin/io/tolgee/websocket/RedisWebsocketEventPublisher.kt

@@ -1,16 +1,17 @@
 package io.tolgee.websocket
 
 import org.springframework.data.redis.core.StringRedisTemplate
-import tools.jackson.module.kotlin.jacksonObjectMapper
+import tools.jackson.databind.ObjectMapper
 
 class RedisWebsocketEventPublisher(
   private val redisTemplate: StringRedisTemplate,
+  private val objectMapper: ObjectMapper,
 ) : WebsocketEventPublisher {
   override operator fun invoke(
     destination: String,
     message: WebsocketEvent,
   ) {
-    val messageString = jacksonObjectMapper().writeValueAsString(RedisWebsocketEventWrapper(destination, message))
+    val messageString = objectMapper.writeValueAsString(RedisWebsocketEventWrapper(destination, message))
     redisTemplate.convertAndSend(
       "websocket",
       messageString,

backend/api/src/main/kotlin/io/tolgee/websocket/WebsocketPublisherConfiguration.kt

@@ -6,6 +6,7 @@ import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
 import org.springframework.data.redis.core.StringRedisTemplate
 import org.springframework.messaging.simp.SimpMessagingTemplate
+import tools.jackson.databind.ObjectMapper
 
 @Configuration
 class WebsocketPublisherConfiguration(
@@ -15,7 +16,10 @@ class WebsocketPublisherConfiguration(
   @Bean
   fun websocketEventPublisher(): WebsocketEventPublisher {
     if (websocketProperties.useRedis) {
-      return RedisWebsocketEventPublisher(applicationContext.getBean(StringRedisTemplate::class.java))
+      return RedisWebsocketEventPublisher(
+        applicationContext.getBean(StringRedisTemplate::class.java),
+        applicationContext.getBean(ObjectMapper::class.java),
+      )
     }
     return SimpleWebsocketEventPublisher(applicationContext.getBean(SimpMessagingTemplate::class.java))
   }

backend/data/src/main/kotlin/io/tolgee/batch/BatchJobCancellationManager.kt

@@ -20,7 +20,7 @@ import org.springframework.data.redis.core.StringRedisTemplate
 import org.springframework.stereotype.Component
 import org.springframework.transaction.PlatformTransactionManager
 import org.springframework.transaction.annotation.Transactional
-import tools.jackson.module.kotlin.jacksonObjectMapper
+import tools.jackson.databind.ObjectMapper
 
 @Component
 class BatchJobCancellationManager(
@@ -36,6 +36,7 @@ class BatchJobCancellationManager(
   private val batchJobChunkExecutionQueue: BatchJobChunkExecutionQueue,
   private val concurrentExecutionLauncher: BatchJobConcurrentLauncher,
   private val batchProperties: io.tolgee.configuration.tolgee.BatchProperties,
+  private val objectMapper: ObjectMapper,
 ) : Logging {
   @Transactional
   fun cancel(id: Long) {
@@ -63,7 +64,7 @@ class BatchJobCancellationManager(
     if (usingRedisProvider.areWeUsingRedis) {
       redisTemplate.convertAndSend(
         RedisPubSubReceiverConfiguration.JOB_CANCEL_TOPIC,
-        jacksonObjectMapper().writeValueAsString(id),
+        objectMapper.writeValueAsString(id),
       )
     }
     cancelLocalJob(id)

backend/data/src/main/kotlin/io/tolgee/batch/BatchJobChunkExecutionQueue.kt

@@ -23,7 +23,7 @@ import org.springframework.data.redis.core.StringRedisTemplate
 import org.springframework.scheduling.annotation.Scheduled
 import org.springframework.stereotype.Component
 import org.springframework.transaction.annotation.Transactional
-import tools.jackson.module.kotlin.jacksonObjectMapper
+import tools.jackson.databind.ObjectMapper
 import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.ConcurrentLinkedDeque
 import java.util.concurrent.atomic.AtomicInteger
@@ -35,6 +35,7 @@ class BatchJobChunkExecutionQueue(
   @Lazy
   private val redisTemplate: StringRedisTemplate,
   private val metrics: Metrics,
+  private val objectMapper: ObjectMapper,
 ) : Logging,
   InitializingBean {
   companion object {
@@ -222,7 +223,7 @@ class BatchJobChunkExecutionQueue(
         val event = JobQueueItemsEvent(batch, QueueEventType.ADD)
         redisTemplate.convertAndSend(
           RedisPubSubReceiverConfiguration.JOB_QUEUE_TOPIC,
-          jacksonObjectMapper().writeValueAsString(event),
+          objectMapper.writeValueAsString(event),
         )
       }
       return

backend/data/src/test/kotlin/io/tolgee/batch/BatchJobChunkExecutionQueuePerformanceTest.kt

@@ -14,6 +14,7 @@ import org.junit.jupiter.api.Timeout.ThreadMode.SEPARATE_THREAD
 import org.mockito.kotlin.mock
 import org.slf4j.LoggerFactory
 import org.springframework.data.redis.core.StringRedisTemplate
+import tools.jackson.module.kotlin.jacksonObjectMapper
 import java.util.concurrent.TimeUnit
 import kotlin.time.measureTime
 
@@ -39,6 +40,7 @@ class BatchJobChunkExecutionQueuePerformanceTest {
         usingRedisProvider = mock<UsingRedisProvider>(),
         redisTemplate = mock<StringRedisTemplate>(),
         metrics = Metrics(SimpleMeterRegistry()),
+        objectMapper = jacksonObjectMapper(),
       )
     // The internal structures live in the companion object (static), clear between tests
     executionQueue.clear()

backend/data/src/test/kotlin/io/tolgee/batch/BatchJobChunkExecutionQueueTest.kt

@@ -13,6 +13,7 @@ import org.junit.jupiter.api.BeforeEach
 import org.junit.jupiter.api.Test
 import org.mockito.kotlin.mock
 import org.springframework.data.redis.core.StringRedisTemplate
+import tools.jackson.module.kotlin.jacksonObjectMapper
 import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.CountDownLatch
 import java.util.concurrent.Executors
@@ -31,6 +32,7 @@ class BatchJobChunkExecutionQueueTest {
         usingRedisProvider = mock<UsingRedisProvider>(),
         redisTemplate = mock<StringRedisTemplate>(),
         metrics = Metrics(SimpleMeterRegistry()),
+        objectMapper = jacksonObjectMapper(),
       )
     queue.clear()
   }