feat(secret): convert a secret to an EnvValue (#1643) (#1647)

# Backport

This will backport the following commits from `k8s-25/main` to `k8s-23/main`:
 - [feat(secret): convert a secret to an `EnvValue` (#1643)](#1643)



### Questions ?
Please refer to the [Backport tool documentation](https://github.com/sqren/backport)

src/secret.ts

@@ -1,6 +1,7 @@
 import { ApiObject } from 'cdk8s';
 import { Construct } from 'constructs';
 import * as base from './base';
+import { EnvValue, EnvValueFromSecretOptions } from './container';
 import * as k8s from './imports/k8s';
 import * as serviceaccount from './service-account';
 
@@ -42,7 +43,12 @@ export interface SecretProps extends CommonSecretProps {
 }
 
 export interface ISecret extends base.IResource {
-
+  /**
+   * Returns EnvValue object from a secret's key.
+   * @param key Secret's key
+   * @param options Additional EnvValue options
+   */
+  envValue(key: string, options?: EnvValueFromSecretOptions): EnvValue;
 }
 
 /**
@@ -91,6 +97,10 @@ class ImportedSecret extends Construct implements ISecret {
     return this.name;
   }
 
+  public envValue(key: string, options?: EnvValueFromSecretOptions): EnvValue {
+    return EnvValue.fromSecretValue({ secret: this, key }, options);
+  }
+
 }
 
 /**
@@ -154,6 +164,10 @@ export class Secret extends base.Resource implements ISecret {
   public getStringData(key: string): string | undefined {
     return this.stringData[key];
   }
+
+  public envValue(key: string, options?: EnvValueFromSecretOptions): EnvValue {
+    return EnvValue.fromSecretValue({ secret: this, key }, options);
+  }
 }
 
 /**

test/container.test.ts

@@ -47,6 +47,36 @@ describe('EnvValue', () => {
     });
   });
 
+  test('Can be created from ISecret.envValue', () => {
+    const chart = Testing.chart();
+
+    const actual = kplus.Secret.fromSecretName(chart, 'Secret', 'Secret').envValue('my-key', { optional: false });
+
+    expect(actual.value).toBeUndefined();
+    expect(actual.valueFrom).toEqual({
+      secretKeyRef: {
+        key: 'my-key',
+        name: 'Secret',
+        optional: false,
+      },
+    });
+  });
+
+  test('Can be created from new secret.envValue', () => {
+    const chart = Testing.chart();
+
+    const actual = new kplus.Secret(chart, 'Secret', { stringData: { 'my-key': 'my-value' } }).envValue('my-key', { optional: true });
+
+    expect(actual.value).toBeUndefined();
+    expect(actual.valueFrom).toEqual({
+      secretKeyRef: {
+        key: 'my-key',
+        name: 'test-secret-c837fa76',
+        optional: true,
+      },
+    });
+  });
+
   test('Cannot be created from missing required process env', () => {
 
     const key = 'cdk8s-plus.tests.container.env.fromProcess';