added admin endpoint to regenerate missing thumbnails

fix admin endpoint to regenerate thumbnails which would block instead of returning. Added task management with single capacity, so subsequent calls will be dropped if a task is running
more logs with book url for errors
expose configuration for number of threads for the parsing executor
add single capacity task executor for periodic scans, so subsequent scans will be skipped if one is already running

komga/src/main/kotlin/org/gotson/komga/domain/persistence/BookRepository.kt

@@ -14,4 +14,5 @@ interface BookRepository : JpaRepository<Book, Long> {
   fun findByUrl(url: URL): Book?
   fun findAllByMetadataStatus(status: Status): List<Book>
   fun findAllByMetadataStatusAndSerieId(status: Status, serieId: Long, pageable: Pageable): Page<Book>
+  fun findAllByMetadataThumbnailIsNull(): List<Book>
 }

komga/src/main/kotlin/org/gotson/komga/domain/service/BookManager.kt

@@ -29,10 +29,10 @@ class BookManager(
       try {
         book.metadata = bookParser.parse(book)
       } catch (ex: UnsupportedMediaTypeException) {
-        logger.info(ex) { "Unsupported media type: ${ex.mediaType}" }
+        logger.info(ex) { "Unsupported media type: ${ex.mediaType}. Book: ${book.url}" }
         book.metadata = BookMetadata(status = Status.UNSUPPORTED, mediaType = ex.mediaType)
       } catch (ex: Exception) {
-        logger.error(ex) { "Error while parsing" }
+        logger.error(ex) { "Error while parsing. Book: ${book.url}" }
         book.metadata = BookMetadata(status = Status.ERROR)
       }
       bookRepository.save(book)

komga/src/main/kotlin/org/gotson/komga/domain/service/BookParser.kt

@@ -55,7 +55,7 @@ class BookParser(
     logger.info { "Regenerate thumbnail for book: ${book.url}" }
 
     if (book.metadata.status != Status.READY) {
-      logger.warn { "Book metadata is not ready, cannot generate thumbnail" }
+      logger.warn { "Book metadata is not ready, cannot generate thumbnail. Book: ${book.url}" }
       throw MetadataNotReadyException()
     }
 

komga/src/main/kotlin/org/gotson/komga/domain/service/LibraryManager.kt

@@ -2,11 +2,13 @@ package org.gotson.komga.domain.service
 
 import mu.KotlinLogging
 import org.apache.commons.lang3.time.DurationFormatUtils
+import org.gotson.komga.domain.model.Book
 import org.gotson.komga.domain.model.Library
 import org.gotson.komga.domain.model.Status
 import org.gotson.komga.domain.persistence.BookRepository
 import org.gotson.komga.domain.persistence.SerieRepository
 import org.springframework.data.auditing.AuditingHandler
+import org.springframework.scheduling.annotation.Async
 import org.springframework.stereotype.Service
 import org.springframework.transaction.annotation.Transactional
 import kotlin.system.measureTimeMillis
@@ -95,14 +97,31 @@ class LibraryManager(
     }
   }
 
-  @Synchronized
+  @Async("periodicScanTaskExecutor")
+  fun scanAndParse(library: Library) {
+    logger.info { "Starting periodic library scan" }
+    scanRootFolder(library)
+
+    logger.info { "Starting periodic book parsing" }
+    parseUnparsedBooks()
+  }
+
+  @Async("regenerateThumbnailsTaskExecutor")
   fun regenerateAllThumbnails() {
     logger.info { "Regenerate thumbnail for all books" }
-    val booksToProcess = bookRepository.findAll()
+    generateThumbnails(bookRepository.findAll())
+  }
 
+  @Async("regenerateThumbnailsTaskExecutor")
+  fun regenerateMissingThumbnails() {
+    logger.info { "Regenerate missing thumbnails" }
+    generateThumbnails(bookRepository.findAllByMetadataThumbnailIsNull())
+  }
+
+  private fun generateThumbnails(books: List<Book>) {
     var sumOfTasksTime = 0L
     measureTimeMillis {
-      sumOfTasksTime = booksToProcess
+      sumOfTasksTime = books
           .map { bookManager.regenerateThumbnailAndPersist(it) }
           .map {
             try {
@@ -113,7 +132,7 @@ class LibraryManager(
           }
           .sum()
     }.also {
-      logger.info { "Generated ${booksToProcess.size} thumbnails in ${DurationFormatUtils.formatDurationHMS(it)} (virtual: ${DurationFormatUtils.formatDurationHMS(sumOfTasksTime)})" }
+      logger.info { "Generated ${books.size} thumbnails in ${DurationFormatUtils.formatDurationHMS(it)} (virtual: ${DurationFormatUtils.formatDurationHMS(sumOfTasksTime)})" }
     }
   }
 }

komga/src/main/kotlin/org/gotson/komga/infrastructure/async/AsyncConfiguration.kt

@@ -1,5 +1,6 @@
 package org.gotson.komga.infrastructure.async
 
+import org.gotson.komga.infrastructure.configuration.KomgaProperties
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
 import org.springframework.scheduling.annotation.EnableAsync
@@ -8,11 +9,29 @@ import java.util.concurrent.Executor
 
 @Configuration
 @EnableAsync
-class AsyncConfiguration {
+class AsyncConfiguration(
+    private val komgaProperties: KomgaProperties
+) {
 
-  @Bean
+  @Bean("parseBookTaskExecutor")
   fun parseBookTaskExecutor(): Executor =
       ThreadPoolTaskExecutor().apply {
-        corePoolSize = 2
+        corePoolSize = komgaProperties.threads.parse
+      }
+
+  @Bean("periodicScanTaskExecutor")
+  fun periodicScanTaskExecutor(): Executor =
+      ThreadPoolTaskExecutor().apply {
+        corePoolSize = 1
+        maxPoolSize = 1
+        setQueueCapacity(0)
+      }
+
+  @Bean("regenerateThumbnailsTaskExecutor")
+  fun regenerateThumbnailsTaskExecutor(): Executor =
+      ThreadPoolTaskExecutor().apply {
+        corePoolSize = 1
+        maxPoolSize = 1
+        setQueueCapacity(0)
       }
 }

komga/src/main/kotlin/org/gotson/komga/infrastructure/configuration/KomgaProperties.kt

@@ -2,13 +2,27 @@ package org.gotson.komga.infrastructure.configuration
 
 import org.springframework.boot.context.properties.ConfigurationProperties
 import org.springframework.stereotype.Component
+import org.springframework.validation.annotation.Validated
+import javax.validation.constraints.Min
+import javax.validation.constraints.NotBlank
 
 @Component
 @ConfigurationProperties(prefix = "komga")
+@Validated
 class KomgaProperties {
   var rootFolder: String = ""
   var rootFolderScanCron: String = ""
-  var userPassword: String = "user"
-  var adminPassword: String = "admin"
-}
 
+  @NotBlank
+  var userPassword: String = "user"
+
+  @NotBlank
+  var adminPassword: String = "admin"
+
+  var threads = Threads()
+
+  class Threads {
+    @Min(1)
+    var parse: Int = 2
+  }
+}

komga/src/main/kotlin/org/gotson/komga/interfaces/scheduler/RootScannerController.kt

@@ -9,6 +9,7 @@ import org.springframework.context.annotation.Profile
 import org.springframework.context.event.EventListener
 import org.springframework.scheduling.annotation.Scheduled
 import org.springframework.stereotype.Controller
+import java.util.concurrent.RejectedExecutionException
 
 private val logger = KotlinLogging.logger {}
 
@@ -21,12 +22,11 @@ class RootScannerController(
 
   @EventListener(ApplicationReadyEvent::class)
   @Scheduled(cron = "#{@komgaProperties.rootFolderScanCron ?: '-'}")
-  @Synchronized
   fun scanRootFolder() {
-    logger.info { "Starting periodic library scan" }
-    libraryManager.scanRootFolder(Library("default", komgaProperties.rootFolder))
-
-    logger.info { "Starting periodic book parsing" }
-    libraryManager.parseUnparsedBooks()
+    try {
+      libraryManager.scanAndParse(Library("default", komgaProperties.rootFolder))
+    } catch (e: RejectedExecutionException) {
+      logger.warn { "Another scan is already running, skipping" }
+    }
   }
 }

komga/src/main/kotlin/org/gotson/komga/interfaces/web/AdminController.kt

@@ -1,5 +1,6 @@
 package org.gotson.komga.interfaces.web
 
+import mu.KotlinLogging
 import org.gotson.komga.domain.service.LibraryManager
 import org.springframework.http.HttpStatus
 import org.springframework.security.access.prepost.PreAuthorize
@@ -7,6 +8,10 @@ import org.springframework.web.bind.annotation.PostMapping
 import org.springframework.web.bind.annotation.RequestMapping
 import org.springframework.web.bind.annotation.ResponseStatus
 import org.springframework.web.bind.annotation.RestController
+import org.springframework.web.server.ResponseStatusException
+import java.util.concurrent.RejectedExecutionException
+
+private val logger = KotlinLogging.logger {}
 
 @RestController
 @RequestMapping("api/v1/admin")
@@ -15,9 +20,23 @@ class AdminController(
     private val libraryManager: LibraryManager
 ) {
 
-  @PostMapping("rpc/thumbnails/regenerateall")
+  @PostMapping("rpc/thumbnails/regenerate/all")
   @ResponseStatus(HttpStatus.ACCEPTED)
   fun regenerateAllThumbnails() {
-    libraryManager.regenerateAllThumbnails()
+    try {
+      libraryManager.regenerateAllThumbnails()
+    } catch (e: RejectedExecutionException) {
+      throw ResponseStatusException(HttpStatus.SERVICE_UNAVAILABLE, "Thumbnail regeneration task is already running")
+    }
+  }
+
+  @PostMapping("rpc/thumbnails/regenerate/missing")
+  @ResponseStatus(HttpStatus.ACCEPTED)
+  fun regenerateMissingThumbnails() {
+    try {
+      libraryManager.regenerateMissingThumbnails()
+    } catch (e: RejectedExecutionException) {
+      throw ResponseStatusException(HttpStatus.SERVICE_UNAVAILABLE, "Thumbnail regeneration task is already running")
+    }
   }
 }

komga/src/main/resources/application-dev.yml

@@ -1,7 +1,9 @@
 #logging.level.org.springframework.security.web.FilterChainProxy: DEBUG
 komga:
-  root-folder: D:\\files
-#  root-folder-scan-cron: "*/10 * * * * ?"
+  root-folder: D:\\files\\issues
+  threads:
+    parse: 1
+#  root-folder-scan-cron: "*/5 * * * * ?"
 spring:
   profiles:
     include: flyway