feat(core): allow overriding ORM config path via --config (#3924)

Allows to override the config path via `--config` option:

```sh
$ npx mikro-orm debug --config ./my-config.ts
```

This option will be respected also when you run your app, not just when
you use the CLI.

docs/docs/installation.md

@@ -188,13 +188,21 @@ For CLI to be able to access our database, we will need to create `mikro-orm.con
 
 TypeScript is also supported, just enable `useTsNode` flag in our `package.json` file. By default, when `useTsNode` is not enabled, CLI will ignore `.ts` files, so if you want to out-out of this behaviour, enable the `alwaysAllowTs` option. This would be useful if you want to use MikroORM with [Bun](https://bun.sh), which has TypeScript support out of the box. There we can also set up array of possible paths to `mikro-orm.config` file, as well as use different file name. The `package.json` file can be located in the current working directory, or in one of its parent folders.
 
-We can use these environment variables to override CLI settings:
+You can use these environment variables to override the CLI settings:
 
 - `MIKRO_ORM_CLI`: the path to ORM config file
 - `MIKRO_ORM_CLI_USE_TS_NODE`: register ts-node
 - `MIKRO_ORM_CLI_TS_CONFIG_PATH`: path to the tsconfig.json (for ts-node)
 - `MIKRO_ORM_CLI_ALWAYS_ALLOW_TS`: enable `.ts` files to use without ts-node
 
+Alternatively, you can also specify the config path via `--config` option:
+
+```sh
+$ npx mikro-orm debug --config ./my-config.ts
+```
+
+This option will be respected also when you run your app, not just when you use the CLI.
+
 > Do not forget to install `ts-node` when enabling `useTsNode` flag.
 
 > The `useTsNode` is used only when executing the CLI, it is not respected when running our app.

packages/cli/src/CLIConfigurator.ts

@@ -36,6 +36,10 @@ export class CLIConfigurator {
       .version(version)
       .usage('Usage: $0 <command> [options]')
       .example('$0 schema:update --run', 'Runs schema synchronization')
+      .option('config', {
+        type: 'string',
+        desc: `Set path to the ORM configuration file`,
+      })
       .alias('v', 'version')
       .alias('h', 'help')
       .command(new ClearCacheCommand())

packages/core/src/utils/ConfigurationLoader.ts

@@ -86,6 +86,12 @@ export class ConfigurationLoader {
   }
 
   static async getConfigPaths(): Promise<string[]> {
+    const options = Utils.parseArgs();
+
+    if (options.config) {
+      return [options.config];
+    }
+
     const paths: string[] = [];
     const settings = await ConfigurationLoader.getSettings();
 

packages/core/src/utils/Utils.ts

@@ -1167,4 +1167,25 @@ export class Utils {
     return str.replace(/^(?:\.\.\/|\.\/)+/, '/');
   }
 
+  /**
+   * simple process.argv parser, supports only properties with long names, prefixed with `--`
+   */
+  static parseArgs<T extends Dictionary = Dictionary>(): T {
+    let lastKey: string | undefined;
+
+    return process.argv.slice(2).reduce((args, arg) => {
+      if (arg.includes('=')) {
+        const [key, value] = arg.split('=');
+        args[key.substring(2)] = value;
+      } else if (lastKey) {
+        args[lastKey] = arg;
+        lastKey = undefined;
+      } else if (arg.startsWith('--')) {
+        lastKey = arg.substring(2);
+      }
+
+      return args;
+    }, {} as Dictionary) as T;
+  }
+
 }

tests/features/cli/CLIHelper.test.ts

@@ -438,6 +438,13 @@ Maybe you want to check, or regenerate your yarn.lock or package-lock.json file?
   });
 
   test('getConfigPaths', async () => {
+    (global as any).process.argv = ['node', 'start.js', '--config', './override1/orm-config.ts'];
+    await expect(CLIHelper.getConfigPaths()).resolves.toEqual(['./override1/orm-config.ts']);
+    (global as any).process.argv = ['node', 'start.js', '--config=./override2/orm-config.ts'];
+    await expect(CLIHelper.getConfigPaths()).resolves.toEqual(['./override2/orm-config.ts']);
+    (global as any).process.argv = ['npx', 'mikro-orm', 'debug', '--config', './override3/orm-config.ts'];
+    await expect(CLIHelper.getConfigPaths()).resolves.toEqual(['./override3/orm-config.ts']);
+    (global as any).process.argv = ['node', 'start.js'];
     (global as any).process.env.MIKRO_ORM_CLI = './override/orm-config.ts';
     await expect(CLIHelper.getConfigPaths()).resolves.toEqual(['./override/orm-config.ts', './src/mikro-orm.config.ts', './mikro-orm.config.ts', './src/mikro-orm.config.js', './mikro-orm.config.js']);
     delete (global as any).process.env.MIKRO_ORM_CLI;