Fixes for Cottontail DB Adapter (#260)

* CottontailSelector.existsEntity() properly handles NOT_FOUND exception. Fixes #255

* Connection output is less verbose. What is logged is logged at DEBUG level now. Addresses #258

* Initialization steps are now wrapped in a try...catch block, which should prevent failing components from killing the CLI. Addresses #257

* More fine-grained try...catch blocks, so that we know exactly, which component failed.

* Removed try...catch around server.start()

Co-authored-by: Ralph Gasser <[email protected]>
Former-commit-id: d9efa6b

cineast-api/src/main/java/org/vitrivr/cineast/api/GRPCEndpoint.java

@@ -18,7 +18,7 @@ public class GRPCEndpoint {
 
   private static final Logger LOGGER = LogManager.getLogger();
 
-  public static void start() {
+  public static void start() throws IOException {
 
     if (!Config.sharedConfig().getApi().getEnableGRPC()) {
       return;
@@ -27,17 +27,12 @@ public static void start() {
     int port = Config.sharedConfig().getApi().getGrpcPort();
 
     LOGGER.info("Starting GRPC Endpoint at port {}", port);
-
     server = ServerBuilder.forPort(port).addService(new CineastQueryService(APIEndpoint.retrievalLogic)) //FIXME this should come from a more reasonable location
         .addService(new CineastExtractionService()).addService(new CineastManagementService()).build();
-
-    try {
-      server.start();
-    } catch (IOException e) {
-    }
-
+    server.start();
   }
 
+
   public static void stop() {
     if (server == null || server.isShutdown()) {
       return;
@@ -51,5 +46,4 @@ public static void stop() {
     }
     server.shutdownNow();
   }
-
 }

cineast-api/src/main/java/org/vitrivr/cineast/api/Main.java

@@ -27,12 +27,26 @@ public static void main(String[] args) {
       }
     }
 
-    /* Start Cineast API endpoint. */
-    APIEndpoint.getInstance().start();
-    GRPCEndpoint.start();
+    /* Start API endpoint. */
+    try {
+      APIEndpoint.getInstance().start();
+    } catch (Throwable e) {
+      System.err.println("Failed to initialize API endpoint due to an exception: " + e.getMessage());
+    }
+
+    /* Start gRPC endpoint. */
+    try {
+      GRPCEndpoint.start();
+    } catch (Throwable e) {
+      System.err.println("Failed to initialize gRPC endpoint due to an exception: " + e.getMessage());
+    }
 
-    /* Initalize Monitoring */
-    PrometheusServer.initialize();
+    /* Initialize Monitoring */
+    try {
+      PrometheusServer.initialize();
+    } catch (Throwable e) {
+      System.err.println("Failed to initialize Monitoring due to an exception: " + e.getMessage());
+    }
 
     /* Start Cineast CLI in interactive mode (blocking). */
     CLI.start(CineastCli.class);

cineast-core/src/main/java/org/vitrivr/cineast/core/db/cottontaildb/CottontailSelector.java

@@ -5,6 +5,7 @@
 import static org.vitrivr.cineast.core.util.CineastConstants.GENERIC_ID_COLUMN_QUALIFIER;
 import static org.vitrivr.cineast.core.util.CineastConstants.KEY_COL_NAME;
 
+import io.grpc.Status.Code;
 import io.grpc.StatusRuntimeException;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -344,8 +345,13 @@ public boolean existsEntity(String name) {
     final AboutEntity about = new AboutEntity(this.cottontail.fqnInput(name));
     try (final TupleIterator results = this.cottontail.client.about(about)) {
       return results.hasNext();
+    } catch (StatusRuntimeException e) {
+      if (e.getStatus().getCode() != Code.NOT_FOUND) {
+        LOGGER.error("Error occurred during query execution in existsEntity(): {}!", e.getMessage());
+      }
+      return false;
     } catch (Exception e) {
-      LOGGER.error("Failed to close TupleIterator!", e);
+      LOGGER.error("Error occurred during query execution in existsEntity(): {}!", e.getMessage());
       return false;
     }
   }

cineast-core/src/main/java/org/vitrivr/cineast/core/db/cottontaildb/CottontailWrapper.java

@@ -65,11 +65,11 @@ private static ManagedChannel createChannel(String host, int port) {
     final NettyChannelBuilder builder = NettyChannelBuilder.forAddress(host, port).usePlaintext();
     final ManagedChannel channel = builder.build();
     Runtime.getRuntime().addShutdownHook(new Thread(() -> {
-      LOGGER.info("Closing connection to Cottontail DB.");
+      LOGGER.debug("Closing connection to Cottontail DB.");
       channel.shutdownNow();
     }));
     watch.stop();
-    LOGGER.info("Connected to Cottontail DB in {} ms at {}:{}", watch.getTime(TimeUnit.MILLISECONDS), host, port);
+    LOGGER.debug("Connected to Cottontail DB in {} ms at {}:{}", watch.getTime(TimeUnit.MILLISECONDS), host, port);
     return channel;
   }
 
@@ -91,11 +91,7 @@ public CottontailWrapper(String host, int port) {
     this.client = new SimpleClient(sharedChannel(host, port));
     boolean pingSuccessful = this.client.ping();
     watch.stop();
-    if (pingSuccessful) {
-      LOGGER.info("Connected to Cottontail in {} ms at {}:{}", watch.getTime(TimeUnit.MILLISECONDS), host, port);
-    } else {
-      LOGGER.warn("Could not connect to Cottontail at {}:{}", host, port);
-    }
+    if (!pingSuccessful) LOGGER.warn("Could not ping Cottontail DB instance at {}:{}", host, port);
   }
 
   /**

cineast-runtime/src/main/java/org/vitrivr/cineast/standalone/Main.java

@@ -20,8 +20,12 @@ public static void main(String[] args) {
       System.exit(1);
     }
 
-    /* Initalize Monitoring */
-    PrometheusServer.initialize();
+    /* Initialize Monitoring */
+    try {
+      PrometheusServer.initialize();
+    } catch (Throwable e) {
+      System.err.println("Failed to initialize Monitoring due to an exception: " + e.getMessage());
+    }
 
     if (args.length == 1) {
       CLI.start(CineastCli.class);