Fix for SQLite DB busy error on Azure (#1395)

depending on an environmental variable is used either 
default locking mode or a mode that uses flock syscall

engine/language-server/src/main/scala/org/enso/languageserver/boot/DeploymentType.scala

@@ -0,0 +1,40 @@
+package org.enso.languageserver.boot
+
+/** Signal where the lang. server is deployed.
+  */
+sealed trait DeploymentType
+
+object DeploymentType {
+
+  /** Desktop deployment.
+    */
+  case object Desktop extends DeploymentType
+
+  /** Azure deployment.
+    */
+  case object Azure extends DeploymentType
+
+  /** Determines the current deployment type from environment variables.
+    * @return the current deployment type
+    */
+  def fromEnvironment(): DeploymentType = {
+    if (sys.env.contains(DeploymentTypeVariableName)) {
+      val value = sys.env(DeploymentTypeVariableName)
+      fromString(value)
+    } else {
+      Desktop
+    }
+  }
+
+  /** Determines a current deployment type from a string value.
+    * @return a deployment type
+    */
+  def fromString(value: String): DeploymentType =
+    value.toLowerCase.trim match {
+      case "desktop" | "" => Desktop
+      case "azure"        => Azure
+    }
+
+  private lazy val DeploymentTypeVariableName = "DEPLOYMENT_TYPE"
+
+}

engine/language-server/src/main/scala/org/enso/languageserver/boot/MainModule.scala

@@ -5,6 +5,7 @@ import java.net.URI
 
 import akka.actor.ActorSystem
 import org.enso.jsonrpc.JsonRpcServer
+import org.enso.languageserver.boot.DeploymentType.{Azure, Desktop}
 import org.enso.languageserver.capability.CapabilityRouter
 import org.enso.languageserver.data._
 import org.enso.languageserver.effect.ZioExec
@@ -34,6 +35,7 @@ import org.enso.languageserver.util.binary.BinaryEncoder
 import org.enso.loggingservice.{JavaLoggingLogHandler, LogLevel}
 import org.enso.polyglot.{LanguageInfo, RuntimeOptions, RuntimeServerInfo}
 import org.enso.searcher.sql.{SqlDatabase, SqlSuggestionsRepo, SqlVersionsRepo}
+import org.enso.searcher.sqlite.LockingMode
 import org.enso.text.{ContentBasedVersioning, Sha3_224VersionCalculator}
 import org.graalvm.polyglot.Context
 import org.graalvm.polyglot.io.MessageEndpoint
@@ -84,7 +86,19 @@ class MainModule(serverConfig: LanguageServerConfig, logLevel: LogLevel) {
   log.trace("Created ActorSystem")
 
   val sqlDatabase =
-    SqlDatabase(languageServerConfig.directories.suggestionsDatabaseFile)
+    DeploymentType.fromEnvironment() match {
+      case Desktop =>
+        SqlDatabase(
+          languageServerConfig.directories.suggestionsDatabaseFile.toString
+        )
+
+      case Azure =>
+        SqlDatabase(
+          languageServerConfig.directories.suggestionsDatabaseFile.toString,
+          Some(LockingMode.UnixFlock)
+        )
+    }
+
   val suggestionsRepo = new SqlSuggestionsRepo(sqlDatabase)(system.dispatcher)
   val versionsRepo    = new SqlVersionsRepo(sqlDatabase)(system.dispatcher)
   log.trace("Created SQL Repos")

engine/language-server/src/test/scala/org/enso/languageserver/search/SuggestionsHandlerSpec.scala

@@ -19,11 +19,11 @@ import org.enso.languageserver.session.JsonSession
 import org.enso.languageserver.session.SessionRouter.DeliverToJsonController
 import org.enso.polyglot.data.Tree
 import org.enso.polyglot.runtime.Runtime.Api
-import org.enso.searcher.{FileVersionsRepo, SuggestionsRepo}
 import org.enso.searcher.sql.{SqlDatabase, SqlSuggestionsRepo, SqlVersionsRepo}
+import org.enso.searcher.{FileVersionsRepo, SuggestionsRepo}
 import org.enso.testkit.RetrySpec
-import org.enso.text.{ContentVersion, Sha3_224VersionCalculator}
 import org.enso.text.editing.model.Position
+import org.enso.text.{ContentVersion, Sha3_224VersionCalculator}
 import org.scalatest.BeforeAndAfterAll
 import org.scalatest.matchers.should.Matchers
 import org.scalatest.wordspec.AnyWordSpecLike
@@ -594,10 +594,12 @@ class SuggestionsHandlerSpec
   ): Unit = {
     val testContentRoot = Files.createTempDirectory(null).toRealPath()
     sys.addShutdownHook(FileUtils.deleteQuietly(testContentRoot.toFile))
-    val config          = newConfig(testContentRoot.toFile)
-    val router          = TestProbe("session-router")
-    val connector       = TestProbe("runtime-connector")
-    val sqlDatabase     = SqlDatabase(config.directories.suggestionsDatabaseFile)
+    val config    = newConfig(testContentRoot.toFile)
+    val router    = TestProbe("session-router")
+    val connector = TestProbe("runtime-connector")
+    val sqlDatabase = SqlDatabase(
+      config.directories.suggestionsDatabaseFile.toString
+    )
     val suggestionsRepo = new SqlSuggestionsRepo(sqlDatabase)
     val versionsRepo    = new SqlVersionsRepo(sqlDatabase)
     val handler = newSuggestionsHandler(

engine/language-server/src/test/scala/org/enso/languageserver/websocket/json/BaseServerTest.scala

@@ -81,13 +81,13 @@ class BaseServerTest extends JsonRpcServerTestKit {
       InputRedirectionController.props(stdIn, stdInSink, sessionRouter)
     )
 
+  val zioExec = ZioExec(zio.Runtime.default)
+  val sqlDatabase =
+    SqlDatabase(config.directories.suggestionsDatabaseFile.toString)
+  val suggestionsRepo = new SqlSuggestionsRepo(sqlDatabase)(system.dispatcher)
+  val versionsRepo    = new SqlVersionsRepo(sqlDatabase)(system.dispatcher)
+
   override def clientControllerFactory: ClientControllerFactory = {
-
-    val zioExec         = ZioExec(zio.Runtime.default)
-    val sqlDatabase     = SqlDatabase(config.directories.suggestionsDatabaseFile)
-    val suggestionsRepo = new SqlSuggestionsRepo(sqlDatabase)(system.dispatcher)
-    val versionsRepo    = new SqlVersionsRepo(sqlDatabase)(system.dispatcher)
-
     val fileManager =
       system.actorOf(FileManager.props(config, new FileSystem, zioExec))
     val bufferRegistry =

lib/scala/searcher/src/main/resources/reference.conf

@@ -4,6 +4,7 @@ searcher {
     driver = "org.sqlite.JDBC"
     connectionPool = disabled
     properties.journal_mode = "wal"
+    properties.locking_mode = "EXCLUSIVE"
     numThreads = 1
   }
 }

lib/scala/searcher/src/main/scala/org/enso/searcher/sql/SqlDatabase.scala

@@ -1,9 +1,8 @@
 package org.enso.searcher.sql
 
-import java.io.File
-
 import com.typesafe.config.{Config, ConfigFactory}
 import org.enso.searcher.Database
+import org.enso.searcher.sqlite.LockingMode
 import slick.dbio.DBIO
 import slick.jdbc.SQLiteProfile
 import slick.jdbc.SQLiteProfile.api._
@@ -43,24 +42,31 @@ object SqlDatabase {
     * @param filename the database file path
     * @return new sql database instance
     */
-  def apply(filename: File): SqlDatabase =
-    apply(filename.toString)
-
-  /** Create [[SqlDatabase]] instance.
-    *
-    * @param filename the database file path
-    * @return new sql database instance
-    */
-  def apply(filename: String): SqlDatabase = {
+  def apply(
+    filename: String,
+    maybeLockingMode: Option[LockingMode] = None
+  ): SqlDatabase = {
     val config = ConfigFactory
-      .parseString(s"""$configPath.url = "${jdbcUrl(filename)}"""")
+      .parseString(
+        s"""$configPath.url = "${jdbcUrl(filename, maybeLockingMode)}""""
+      )
       .withFallback(ConfigFactory.load())
     new SqlDatabase(Some(config))
   }
 
   /** Create JDBC URL from the file path. */
-  private def jdbcUrl(filename: String): String =
-    s"jdbc:sqlite:${escapePath(filename)}"
+  private def jdbcUrl(
+    filename: String,
+    maybeLockingMode: Option[LockingMode]
+  ): String = {
+    maybeLockingMode match {
+      case None =>
+        s"jdbc:sqlite:${escapePath(filename)}"
+
+      case Some(lockingMode) =>
+        s"jdbc:sqlite:file:${escapePath(filename)}?vfs=${lockingMode.name}"
+    }
+  }
 
   /** Escape Windows path. */
   private def escapePath(path: String): String =

lib/scala/searcher/src/main/scala/org/enso/searcher/sqlite/LockingMode.scala

@@ -0,0 +1,24 @@
+package org.enso.searcher.sqlite
+
+/** A mode used to handle file locking in SQLite */
+case class LockingMode private (name: String)
+
+object LockingMode {
+
+  /** Default mode that uses POSIX advisory locks.
+    */
+  val UnixPosix = LockingMode("unix")
+
+  /** It obtains and holds an exclusive lock on database files,
+    * preventing other processes from accessing the database.
+    * It uses the `flock` system call.
+    */
+  val UnixFlock = LockingMode("unix-excl")
+
+  /** It uses dot-file locking rather than POSIX advisory locks. */
+  val UnixDotFile = LockingMode("unix-dotfile")
+
+  /** All file locking operations are no-ops. */
+  val UnixNone = LockingMode("unix-none")
+
+}

tools/ci/docker/Dockerfile

@@ -11,9 +11,9 @@ ADD runtime.jar /opt/enso/runtime.jar
 RUN chown -hR enso:enso /opt/enso
 RUN chmod -R u=rX,g=rX /opt/enso
 
-RUN mkdir -p /home/enso/workspace
-RUN chown -hR enso:enso /home/enso/workspace
-RUN chmod -R u=rwX,g=rwX /home/enso/workspace
+RUN mkdir -p /volumes
+RUN chown -hR enso:enso /volumes
+RUN chmod -R u=rwX,g=rwX /volumes
 
 USER enso:enso
 
@@ -24,7 +24,6 @@ ENTRYPOINT ["java", "-jar",  "-Dtruffle.class.path.append=runtime.jar", "-Dpolyg
 EXPOSE 30001
 EXPOSE 30002
 
-VOLUME /home/enso/workspace
-
-CMD ["--server", "--rpc-port", "30001", "--data-port", "30002", "--root-id", "00000000-0000-0000-0000-000000000001", "--path", "/home/enso/workspace", "--interface", "0.0.0.0"]
+VOLUME /volumes/workspace
 
+CMD ["--server", "--daemon", "--rpc-port", "30001", "--data-port", "30002", "--root-id", "00000000-0000-0000-0000-000000000001", "--path", "/volumes/workspace", "--interface", "0.0.0.0", "--log-level", "INFO"]