feat(cli): support loading auth-token from env var

Support loading the auth token and Mermaid Chart base URL from
environment variables using `MERMAID_CHART_AUTH_TOKEN` and
`MERMAID_CHART_BASE_URL`.

The order of priority is:
  1. CLI --options
  2. Environment variables
  3. Config file
  4. Default values

Author: aloisklink

packages/cli/src/commander.test.ts

@@ -1,4 +1,4 @@
-import { beforeAll, beforeEach, describe, expect, vi, it, type Mock } from 'vitest';
+import { afterEach, beforeAll, beforeEach, describe, expect, vi, it, type Mock } from 'vitest';
 import { createCommanderCommand } from './commander.js';
 import { copyFile, mkdir, readFile, rm } from 'node:fs/promises';
 import type { Command, CommanderError, OutputConfiguration } from '@commander-js/extra-typings';
@@ -106,6 +106,10 @@ describe('--version', () => {
 });
 
 describe('whoami', () => {
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
   it('should error if --config file does not exist', async () => {
     const { program } = mockedProgram();
 
@@ -136,11 +140,13 @@ describe('whoami', () => {
     ).rejects.toThrowError('Invalid access token.');
   });
 
-  it('--auth-token should override config file', async () => {
+  it('--auth-token should override config file and environment variables', async () => {
     const { program } = mockedProgram();
 
     const myCliAuthToken = 'my-cli-auth-token';
 
+    vi.stubEnv('MERMAID_CHART_AUTH_TOKEN', 'my-env-auth-token');
+
     await program.parseAsync(
       ['--config', CONFIG_AUTHED, '--auth-token', myCliAuthToken, 'whoami'],
       { from: 'user' },
@@ -157,6 +163,21 @@ describe('whoami', () => {
 
     expect(consoleLogSpy).toBeCalledWith(mockedMCUser.emailAddress);
   });
+
+  it('should support loading auth from environment variables', async () => {
+    const { program } = mockedProgram();
+
+    const authToken = 'my-api-key-from-env-var';
+    vi.stubEnv('MERMAID_CHART_AUTH_TOKEN', authToken);
+    vi.stubEnv('MERMAID_CHART_BASE_URL', 'https://test.mermaidchart.invalid');
+
+    const consoleLogSpy = vi.spyOn(global.console, 'log');
+    await program.parseAsync(['--config', CONFIG_AUTHED, 'whoami'], { from: 'user' });
+
+    // environment variables should override config file
+    expect(vi.mocked(MermaidChart.prototype.setAccessToken)).toHaveBeenCalledWith(authToken);
+    expect(consoleLogSpy).toBeCalledWith(mockedMCUser.emailAddress);
+  });
 });
 
 describe('login', () => {

packages/cli/src/commander.ts

@@ -296,12 +296,15 @@ export function createCommanderCommand() {
       defaultConfigPath(),
     )
     .addOption(
-      new Option(
-        '--base-url <base_url>',
-        'The base URL of the Mermaid Chart instance to use.',
-      ).default('https://mermaidchart.com'),
+      new Option('--base-url <base_url>', 'The base URL of the Mermaid Chart instance to use.')
+        .default('https://mermaidchart.com')
+        .env('MERMAID_CHART_BASE_URL'),
+    )
+    .addOption(
+      new Option('--auth-token <auth_token>', 'The Mermaid Chart API token to use.').env(
+        'MERMAID_CHART_AUTH_TOKEN',
+      ),
     )
-    .addOption(new Option('--auth-token <auth_token>', 'The Mermaid Chart API token to use.'))
     .hook('preSubcommand', async (command, actionCommand) => {
       const configPath = command.getOptionValue('config');
       /**