add kafka producer, move configs to separate package

src/main/kotlin/com/example/demo/config/AppConfig.kt

@@ -0,0 +1,39 @@
+package com.example.demo.config
+
+import com.example.demo.provider.CityRepository
+import com.example.demo.provider.MockedShopProvider
+import com.example.demo.provider.ProductRepository
+import com.example.demo.provider.ShopProvider
+import com.example.demo.services.CityService
+import com.example.demo.services.CityServiceImpl
+import com.example.demo.services.ProductService
+import com.example.demo.services.ProductServiceImpl
+import com.example.demo.services.kafka.Producer
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.beans.factory.annotation.Value
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+
+@Configuration
+class AppConfig(
+    @Value("\${kafka.producer.product.default-sync-topic}")
+    private val defaultProductSyncTopic: String
+) {
+    @Bean
+    fun shopProvider(): ShopProvider{
+        return MockedShopProvider()
+    }
+
+    @Bean
+    fun productService(
+        @Autowired productRepository: ProductRepository,
+        @Autowired producer: Producer,
+    ): ProductService = ProductServiceImpl(
+        defaultProductSyncTopic,
+        productRepository,
+        producer,
+    )
+
+    @Bean
+    fun cityService(@Autowired cityRepository: CityRepository): CityService = CityServiceImpl(cityRepository)
+}

src/main/kotlin/com/example/demo/config/ProducerConfig.kt

@@ -0,0 +1,40 @@
+package com.example.demo.config
+
+import com.example.demo.services.kafka.Producer
+import com.example.demo.services.kafka.ProducerImpl
+import com.example.demo.services.kafka.dto.serializer.ProductSerializer
+import org.apache.kafka.clients.producer.ProducerConfig
+import org.apache.kafka.common.serialization.StringSerializer
+import org.springframework.beans.factory.annotation.Value
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+import org.springframework.kafka.core.DefaultKafkaProducerFactory
+import org.springframework.kafka.core.KafkaTemplate
+import org.springframework.kafka.core.ProducerFactory
+
+@Configuration
+class ProducerConfig(
+    @Value("\${kafka.bootstrap-servers}")
+    val servers: String
+) {
+    @Bean
+    fun producerFactory(): ProducerFactory<String, Any> {
+        val configProps: MutableMap<String, Any> = HashMap()
+
+        configProps[ProducerConfig.BOOTSTRAP_SERVERS_CONFIG] = servers
+        configProps[ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG] = StringSerializer::class.java
+        configProps[ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG] = ProductSerializer::class.java
+
+        return DefaultKafkaProducerFactory(configProps)
+    }
+
+    @Bean
+    fun kafkaTemplate(): KafkaTemplate<String, Any> = KafkaTemplate(
+        producerFactory(),
+    )
+
+    @Bean
+    fun producer(): Producer = ProducerImpl(
+        kafkaTemplate(),
+    )
+}