feat(ec2): add support for environment files and variables in systemd

packages/aws-cdk-lib/aws-ec2/lib/cfn-init-elements.ts

@@ -835,6 +835,10 @@ export class InitService extends InitElement {
       throw new Error(`SystemD executables must use an absolute path, got '${options.command}'`);
     }
 
+    if (options.environmentFiles?.some(file => !file.startsWith('/'))) {
+      throw new Error('SystemD environment files must use absolute paths');
+    }
+
     const lines = [
       '[Unit]',
       ...(options.description ? [`Description=${options.description}`] : []),
@@ -845,6 +849,17 @@ export class InitService extends InitElement {
       ...(options.user ? [`User=${options.user}`] : []),
       ...(options.group ? [`Group=${options.user}`] : []),
       ...(options.keepRunning ?? true ? ['Restart=always'] : []),
+      ...(
+        options.environmentFiles
+          ? options.environmentFiles.map(file => `EnvironmentFile=${file}`)
+          : []
+      ),
+      ...(
+        options.environmentVariables
+          ? Object.entries(options.environmentVariables)
+            .map(([key, value]) => `Environment="${key}=${value}"`)
+          : []
+      ),
       '[Install]',
       'WantedBy=multi-user.target',
     ];
@@ -1108,4 +1123,18 @@ export interface SystemdConfigFileOptions {
    * @default true
    */
   readonly afterNetwork?: boolean;
-}
+
+  /**
+   * Include environment variables when process is running
+   *
+   * @default - No environment variables set
+   */
+  readonly environmentVariables?: Record<string, string>;
+
+  /**
+   * Include file to load environment variables from when process is running
+   *
+   * @default - No environment files
+   */
+  readonly environmentFiles?: string[];
+}

packages/aws-cdk-lib/aws-ec2/test/cfn-init-element.test.ts

@@ -727,6 +727,35 @@ describe('InitService', () => {
     expect(capture).toContain('Group=ec2-user');
     expect(capture).toContain('Description=my service');
   });
+
+  test('can create systemd file with environment variables', () => {
+    // WHEN
+    const file = ec2.InitService.systemdConfigFile('myserver', {
+      command: '/start/my/service',
+      cwd: '/my/dir',
+      user: 'ec2-user',
+      group: 'ec2-user',
+      description: 'my service',
+      environmentFiles: ['/files/one', '/files/two'],
+      environmentVariables: {
+        HELLO: 'WORLD',
+      },
+    });
+
+    // THEN
+    const bindOptions = defaultOptions(InitPlatform.LINUX);
+    const rendered = file._bind(bindOptions).config;
+    expect(rendered).toEqual({
+      '/etc/systemd/system/myserver.service': expect.objectContaining({
+        content: expect.any(String),
+      }),
+    });
+
+    const capture = rendered['/etc/systemd/system/myserver.service'].content;
+    expect(capture).toContain('EnvironmentFile=/files/one');
+    expect(capture).toContain('EnvironmentFile=/files/two');
+    expect(capture).toContain('Environment="HELLO=WORLD"');
+  });
 });
 
 describe('InitSource', () => {