Added KERNEL PANIC message when commands crash unexpectedly, so I can take a look at it later, and it doesn't break the command

Signed-off-by: Louis Vallat <louis@louis-vallat.xyz>

src/main/java/xyz/vallat/louis/MoviesQuoteBot.java

@@ -11,7 +11,7 @@ public class MoviesQuoteBot {
     public static final String PREFIX = "!";
     public static final String NAME = "Movies Quote Bot";
     public static final String DESCRIPTION = "I may know some quotes from some movies.";
-    public static final String VERSION = "0.3.4-SNAPSHOT";
+    public static final String VERSION = "0.3.5-SNAPSHOT";
     private static final Logger logger = LoggerFactory.getLogger(MoviesQuoteBot.class.getCanonicalName());
 
     public static void main(String[] args) {

src/main/java/xyz/vallat/louis/commands/Command.java

@@ -6,6 +6,7 @@ import discord4j.core.object.reaction.ReactionEmoji;
 import discord4j.core.spec.EmbedCreateSpec;
 import discord4j.rest.util.Color;
 import org.apache.commons.cli.Options;
+import org.apache.commons.lang3.RandomStringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import reactor.core.publisher.Mono;
@@ -14,6 +15,7 @@ import xyz.vallat.louis.omdb.objects.Movie;
 import xyz.vallat.louis.subtitles.OpenSubtitles;
 
 import java.io.IOException;
+import java.time.Instant;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Function;
@@ -22,8 +24,9 @@ import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 public abstract class Command {
+
     protected static final ReactionEmoji WAITING = ReactionEmoji.unicode("⌛");
-    private static final Logger logger = LoggerFactory.getLogger(ListLang.class.getCanonicalName());
+    private static final Logger logger = LoggerFactory.getLogger(Command.class.getCanonicalName());
     protected final String name;
     protected final String description;
     protected final String usage;
@@ -81,6 +84,19 @@ public abstract class Command {
                 .then();
     }
 
+    protected Mono<Void> fatalError(MessageCreateEvent event, Throwable throwable) {
+        return event.getMessage().getChannel().flatMap(
+                channel -> channel.createEmbed(embed -> {
+                    event.getMessage().removeSelfReaction(WAITING);
+                    String errorCode = RandomStringUtils.random(8, true, true);
+                    logger.error("KERNEL PANIC: {}", errorCode, throwable);
+                    embed.setTitle("KERNEL PANIC").setColor(Color.RED)
+                            .setDescription("A fatal and unhandled error has been encountered. " +
+                                    "Please transfer this message to my administrator.")
+                            .addField("IDENTIFIER", errorCode, false).setTimestamp(Instant.now());
+                })).then();
+    }
+
     protected void createEmbedListLang(String arg, EmbedCreateSpec embed, boolean isId) {
         try {
             Movie movie = OMDBClient.getMovie(arg, isId);

src/main/java/xyz/vallat/louis/commands/Download.java

@@ -69,7 +69,8 @@ public class Download extends Command {
                                 }
                                 embed.setTimestamp(Instant.now());
                             }
-                    ))).then(event.getMessage().removeSelfReaction(WAITING)).then();
+                    ))).then(event.getMessage().removeSelfReaction(WAITING)).then()
+                    .onErrorResume(throwable -> fatalError(event, throwable));
         } catch (ParseException e) {
             logger.debug("Parsing error: {}", e.getMessage());
             return parsingError(event);

src/main/java/xyz/vallat/louis/commands/Help.java

@@ -22,7 +22,7 @@ public class Help extends Command {
                         embed.addField(command.getName(),
                                 command.getDescription() + " Usage: " + command.getUsage() + ".", false);
                 }
-        )).then();
+        )).then().onErrorResume(throwable -> fatalError(event, throwable));
     }
 }
 

src/main/java/xyz/vallat/louis/commands/ListLang.java

@@ -46,7 +46,8 @@ public class ListLang extends Command {
                                     embed.setDescription("I cannot search for subtitle languages right now. Sorry.");
                                 }
                                 embed.setTimestamp(Instant.now());
-                            })))).then(event.getMessage().removeSelfReaction(WAITING)).then();
+                            })))).then(event.getMessage().removeSelfReaction(WAITING)).then()
+                    .onErrorResume(throwable -> fatalError(event, throwable));
         } catch (ParseException e) {
             logger.debug("Parsing error: {}", e.getMessage());
             return parsingError(event);

src/main/java/xyz/vallat/louis/commands/Ping.java

@@ -13,6 +13,6 @@ public class Ping extends Command {
     public Mono<Void> execute(MessageCreateEvent event) {
         return event.getMessage().getChannel()
                 .flatMap(channel -> channel.createMessage("Pong!"))
-                .then();
+                .then().onErrorResume(throwable -> fatalError(event, throwable));
     }
 }

src/main/java/xyz/vallat/louis/commands/Quote.java

@@ -61,7 +61,7 @@ public class Quote extends Command {
                     }
                 }
                 embed.setTimestamp(Instant.now());
-            })).then();
+            })).then().onErrorResume(throwable -> fatalError(event, throwable));
         } catch (ParseException e) {
             logger.debug("Parsing error: {}", e.getMessage());
             return parsingError(event);

src/main/java/xyz/vallat/louis/commands/Version.java

@@ -45,7 +45,7 @@ public class Version extends Command {
                                 }
                         )
                 )
-                .then();
+                .then().onErrorResume(throwable -> fatalError(event, throwable));
     }
 
 }

src/main/java/xyz/vallat/louis/omdb/OMDBClient.java

@@ -1,6 +1,5 @@
 package xyz.vallat.louis.omdb;
 
-import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
 import org.slf4j.Logger;
@@ -17,8 +16,6 @@ import java.net.http.HttpClient;
 import java.net.http.HttpRequest;
 import java.net.http.HttpResponse;
 import java.nio.charset.StandardCharsets;
-import java.util.ArrayList;
-import java.util.List;
 
 public final class OMDBClient {