feat(placeholders): be able to use environment variables

apps/generator-cli/src/README.md

@@ -175,6 +175,7 @@ is automatically used to generate your code. 🎉
 | relDir       | directory name of file relative to the glob provided          | docs                                                  |
 | relPath      | file name and extension of file relative to the glob provided | docs/auth.yaml                                        |
 | ext          | just file extension                                           | yaml                                                  |
+| env.<name>   | environment variable (use ${env.name} syntax)                 |                                                       |
 
 ### Using custom / private maven registry 
 
@@ -196,6 +197,18 @@ If you're using a private maven registry you can configure the `downloadUrl` and
 
 If the `version` property param is set it is not necessary to configure the `queryUrl`.
 
+`queryUrl` and `downloadUrl` can use the following placeholders:
+
+| placeholder | description                                        |
+|-------------|----------------------------------------------------|
+| groupId     | maven groupId where '.' has been replace with /    |
+| artifactId  | maven artifactId where '.' has been replace with / |
+| versionName | maven version (only for downloadUrl)               |
+| group.id    | maven groupId                                      |
+| artifact.id | maven artifactId                                   |
+| env.<name>  | environment variable name                          |
+
+
 ### Use locally built JAR
 In order to use a locally built jar of the generator CLI, you can copy the jar from your local build (i.e. if you were to `build` the [OpenAPITools/openapi-generator](https://github.com/OpenAPITools/openapi-generator) repository it would be in `~/openapi-generator/modules/openapi-generator-cli/target/openapi-generator-cli.jar`) into `./node_modules/@openapitools/openapi-generator-cli/versions/` and change the `version` in the `openapitools.json` file to the base name of the jar file.
 E.g.:

apps/generator-cli/src/app/services/config.service.spec.ts

@@ -90,6 +90,41 @@ describe('ConfigService', () => {
           );
         });
       });
+
+      describe('the config has values having placeholders', () => {
+        beforeEach(() => {
+          fs.readJSONSync.mockReturnValue({
+            $schema: 'foo.json',
+            spaces: 4,
+            'generator-cli': {
+              version: '1.2.3',
+              repository: {
+                queryUrl: 'https://${env.__unit_test_username}:${env.__unit_test_password}@server/api',
+                downloadUrl: 'https://${env.__unit_test_non_matching}@server/api'
+              }
+            },
+          });
+          process.env['__unit_test_username'] = 'myusername';
+          process.env['__unit_test_password'] = 'mypassword';
+        });
+
+        afterEach(() => {
+          delete process.env['__unit_test_username'];
+          delete process.env['__unit_test_password'];
+        })
+
+        it('verify placeholder replaced with env vars', () => {
+          const value = fixture.get('generator-cli.repository.queryUrl');
+
+          expect(value).toEqual('https://myusername:mypassword@server/api');
+        });
+
+        it('verify placeholders not matching env vars are not replaced', () => {
+          const value = fixture.get('generator-cli.repository.downloadUrl');
+
+          expect(value).toEqual('https://${env.__unit_test_non_matching}@server/api');
+        });
+      });
     });
 
     describe('has()', () => {

apps/generator-cli/src/app/services/config.service.ts

@@ -60,14 +60,43 @@ export class ConfigService {
   private read() {
     fs.ensureFileSync(this.configFile)
 
-    return merge(
+    const config = merge(
       this.defaultConfig,
       fs.readJSONSync(this.configFile, {throws: false, encoding: 'utf8'}),
     )
+
+    return this.replacePlaceholders(config)
   }
 
   private write(config) {
     fs.writeJSONSync(this.configFile, config, {encoding: 'utf8', spaces: config.spaces || 2})
   }
 
+  private replacePlaceholders(config: any): any {
+    const envVariables = Object.fromEntries(
+      Object.entries(process.env).map(([key, value]) => [`env.${key}`, value])
+    );
+    const placeholders = {
+      ...envVariables
+    };
+    const replacePlaceholderInString = (str: string): string => {
+      return str.replace(/\${(.*?)}/g, (match, p1) => {
+          const key = p1.trim();
+          return placeholders[key] !== undefined ? placeholders[key] : match;
+      });
+    };
+    const traverseAndReplace = (obj: any): any => {
+        if (typeof obj === 'string') {
+            return replacePlaceholderInString(obj);
+        } else if (Array.isArray(obj)) {
+            return obj.map(item => traverseAndReplace(item));
+        } else if (obj !== null && typeof obj === 'object') {
+            return Object.fromEntries(
+                Object.entries(obj).map(([key, value]) => [key, traverseAndReplace(value)])
+            );
+        }
+        return obj; // Return the value as is if it's not a string, array, or object
+    };
+    return traverseAndReplace(config);
+  }
 }