Db reset command (#730)

Drop the sys database

src/dbos-runtime/cli.ts

@@ -13,6 +13,7 @@ import { cancelWorkflow, getWorkflow, listWorkflows, reattemptWorkflow } from ".
 import { GetWorkflowsInput, StatusString } from "..";
 import { exit } from "node:process";
 import { runCommand } from "./commands";
+import { reset} from "./reset";
 
 const program = new Command();
 
@@ -118,6 +119,17 @@ program
   .description("Perform a database migration")
   .action(async () => { await runAndLog(migrate); });
 
+program
+  .command('reset')
+  .description("reset the system database")
+  .option('-y, --yes', 'Skip confirmation prompt', false)
+  .action(async (options: {yes: boolean}) => { 
+    const logger = new GlobalLogger();
+    const _ = parseConfigFile(); // Validate config file
+    const configFile = loadConfigFile(dbosConfigFilePath);
+    await reset(configFile, logger, options.yes);
+  });
+
 program
   .command('rollback')
   .action(async () => { await runAndLog(rollbackMigration); });

src/dbos-runtime/reset.ts

@@ -0,0 +1,51 @@
+import { GlobalLogger } from "../telemetry/logs";
+import { ConfigFile, constructPoolConfig } from "./config";
+import { PoolConfig, Client } from "pg";
+import { confirm } from '@inquirer/prompts';
+
+export async function reset(configFile: ConfigFile, logger: GlobalLogger, cnf: boolean) {
+
+  if (cnf) {
+    const userConfirmed = await confirm({
+      message:
+        'This command resets your DBOS system database, deleting metadata about past workflows and steps. Are you sure you want to proceed?',
+      default: false, // Default value for confirmation
+    });
+
+    if (!userConfirmed) {
+      console.log('Operation cancelled.');
+      process.exit(0); // Exit the process if the user cancels
+    }
+  }
+
+  const userPoolConfig: PoolConfig = constructPoolConfig(configFile)
+
+  const sysDbName = configFile.database.sys_db_name ?? `${userPoolConfig.database}_dbos_sys`;
+
+  logger.info(`Resetting ${sysDbName} if it exists`);
+
+  const pgClient  = new Client({
+    user: userPoolConfig.user,
+    host: userPoolConfig.host,
+    database: "postgres", // Connect to the default PostgreSQL database
+    password: userPoolConfig.password,
+    port: userPoolConfig.port,
+  });
+
+  await pgClient.connect();
+
+  console.log("Terminating connections to system database");
+
+
+  await pgClient.query(`SELECT pg_terminate_backend(pg_stat_activity.pid)
+                FROM pg_stat_activity
+                WHERE pg_stat_activity.datname = $1
+                AND pid <> pg_backend_pid()`, [sysDbName]);
+
+
+  await pgClient.query(`DROP DATABASE IF EXISTS ${sysDbName};`);        
+
+  await pgClient.end();
+
+  return 0;
+}