Added migration commands.

src/main/java/com/javadiscord/javabot/data/MigrationUtils.java

@@ -0,0 +1,27 @@
+package com.javadiscord.javabot.data;
+
+import com.javadiscord.javabot.data.commands.MigrationsListSubcommand;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.file.FileSystemNotFoundException;
+import java.nio.file.FileSystems;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.HashMap;
+
+public class MigrationUtils {
+	public static Path getMigrationsDirectory() throws URISyntaxException, IOException {
+		var resource = MigrationsListSubcommand.class.getResource("/migrations/");
+		if (resource == null) throw new IOException("Missing resource /migrations/");
+		var uri = resource.toURI();
+		Path dirPath;
+		try {
+			dirPath =  Paths.get(uri);
+		} catch (FileSystemNotFoundException e) {
+			var env = new HashMap<String, String>();
+			dirPath = FileSystems.newFileSystem(uri, env).getPath("/migrations/");
+		}
+		return dirPath;
+	}
+}

src/main/java/com/javadiscord/javabot/data/commands/DbAdminCommandHandler.java

@@ -5,5 +5,7 @@
 public class DbAdminCommandHandler extends DelegatingCommandHandler {
 	public DbAdminCommandHandler() {
 		this.addSubcommand("export-schema", new ExportSchemaSubcommand());
+		this.addSubcommand("migrations-list", new MigrationsListSubcommand());
+		this.addSubcommand("migrate", new MigrateSubcommand());
 	}
 }

src/main/java/com/javadiscord/javabot/data/commands/MigrateSubcommand.java

@@ -0,0 +1,72 @@
+package com.javadiscord.javabot.data.commands;
+
+import com.javadiscord.javabot.Bot;
+import com.javadiscord.javabot.commands.Responses;
+import com.javadiscord.javabot.commands.SlashCommandHandler;
+import com.javadiscord.javabot.data.MigrationUtils;
+import net.dv8tion.jda.api.events.interaction.SlashCommandEvent;
+import net.dv8tion.jda.api.requests.restaction.interactions.ReplyAction;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.sql.SQLException;
+import java.util.Objects;
+
+/**
+ * This subcommand is responsible for executing SQL migrations on the bot's
+ * schema.
+ * <p>
+ *     It uses the given name (adding .sql if it's not already there) to look
+ *     for a matching file in the /migrations/ resource directory. Once it's
+ *     found the file, it will split it up into a list of statements by the ';'
+ *     character, and then proceed to execute each statement.
+ * </p>
+ */
+public class MigrateSubcommand implements SlashCommandHandler {
+	@Override
+	public ReplyAction handle(SlashCommandEvent event) {
+		String migrationName = Objects.requireNonNull(event.getOption("name")).getAsString();
+		if (!migrationName.endsWith(".sql")) {
+			migrationName = migrationName + ".sql";
+		}
+		try {
+			Path migrationsDir = MigrationUtils.getMigrationsDirectory();
+			Path migrationFile = migrationsDir.resolve(migrationName);
+			if (Files.notExists(migrationFile)) {
+				return Responses.warning(event, "The specified migration `" + migrationName + "` does not exist.");
+			}
+			String sql = Files.readString(migrationFile);
+			String[] statements = sql.split("\\s*;\\s*");
+			if (statements.length == 0) {
+				return Responses.warning(event, "The migration `" + migrationName + "` does not contain any statements. Please remove or edit it before running again.");
+			}
+			Bot.asyncPool.submit(() -> {
+				try (var con = Bot.dataSource.getConnection()) {
+					for (int i = 0; i < statements.length; i++) {
+						if (statements[i].isBlank()) {
+							event.getChannel().sendMessage("Skipping statement " + i + "; it is blank.").complete();
+							continue;
+						}
+						try (var stmt = con.createStatement()){
+							int rowsUpdated = stmt.executeUpdate(statements[i]);
+							event.getChannel().sendMessageFormat(
+									"Executed statement %d of %d:\n```\n%s\n```\nRows Updated: `%d`", i, statements.length, statements[i], rowsUpdated
+							).complete();
+						} catch (SQLException e) {
+							e.printStackTrace();
+							event.getChannel().sendMessage("Error while executing statement " + i + ": " + e.getMessage()).queue();
+							return;
+						}
+					}
+				} catch (SQLException e) {
+					event.getChannel().sendMessage("Could not obtain a connection to the database.").queue();
+				}
+			});
+			return Responses.info(event, "Migration Started", "Execution of the migration `" + migrationName + "` has been started. " + statements.length + " statements will be executed.");
+		} catch (IOException | URISyntaxException e) {
+			return Responses.error(event, e.getMessage());
+		}
+	}
+}

src/main/java/com/javadiscord/javabot/data/commands/MigrationsListSubcommand.java

@@ -0,0 +1,49 @@
+package com.javadiscord.javabot.data.commands;
+
+import com.javadiscord.javabot.commands.Responses;
+import com.javadiscord.javabot.commands.SlashCommandHandler;
+import com.javadiscord.javabot.data.MigrationUtils;
+import net.dv8tion.jda.api.EmbedBuilder;
+import net.dv8tion.jda.api.events.interaction.SlashCommandEvent;
+import net.dv8tion.jda.api.requests.restaction.interactions.ReplyAction;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.file.Files;
+import java.util.stream.Collectors;
+
+/**
+ * This subcommand shows a list of all available migrations, and a short preview
+ * of their source code.
+ */
+public class MigrationsListSubcommand implements SlashCommandHandler {
+	@Override
+	public ReplyAction handle(SlashCommandEvent event) {
+		try (var s = Files.list(MigrationUtils.getMigrationsDirectory())) {
+			EmbedBuilder embedBuilder = new EmbedBuilder()
+					.setTitle("List of Runnable Migrations");
+			var paths = s.filter(path -> path.getFileName().toString().endsWith(".sql")).collect(Collectors.toList());
+			if (paths.isEmpty()) {
+				embedBuilder.setDescription("There are no migrations to run. Please add them to the `/migrations/` resource directory.");
+				return event.replyEmbeds(embedBuilder.build());
+			}
+			paths.forEach(path -> {
+				StringBuilder sb = new StringBuilder(150);
+				sb.append("```sql\n");
+				try {
+					String sql = Files.readString(path);
+					sb.append(sql, 0, Math.min(sql.length(), 100));
+					if (sql.length() > 100) sb.append("...");
+				} catch (IOException e) {
+					e.printStackTrace();
+					sb.append("Error: Could not read SQL: ").append(e.getMessage());
+				}
+				sb.append("\n```");
+				embedBuilder.addField(path.getFileName().toString(), sb.toString(), false);
+			});
+			return event.replyEmbeds(embedBuilder.build());
+		} catch (IOException | URISyntaxException e) {
+			return Responses.error(event, e.getMessage());
+		}
+	}
+}

src/main/resources/commands.yaml

@@ -630,4 +630,13 @@
         - name: include-data
           description: Should data be included in the export?
           required: true
-          type: BOOLEAN
+          type: BOOLEAN
+    - name: migrations-list
+      description: Show a list of all database migrations that can be run.
+    - name: migrate
+      description: Run a database migration.
+      options:
+        - name: name
+          description: The name of the migration to run.
+          required: true
+          type: STRING

src/main/resources/migrations/test.sql

@@ -0,0 +1,4 @@
+// Updates Andrew's account to have the specified number of credits.
+UPDATE ECONOMY_ACCOUNT
+SET BALANCE = 420
+WHERE USER_ID = 235439851263098880;