Support get_type_description service via parameter

Author: minggangw

lib/type_description_service.js

@@ -18,6 +18,12 @@ const loader = require('./interface_loader.js');
 const rclnodejs = require('bindings')('rclnodejs');
 const Service = require('./service.js');
 
+const {
+  ParameterType,
+  Parameter,
+  ParameterDescriptor,
+} = require('../lib/parameter.js');
+
 // This class is used to create a TypeDescriptionService which can be used to
 // retrieve information about types used by the node’s publishers, subscribers,
 // services or actions.
@@ -32,10 +38,30 @@ class TypeDescriptionService {
       'type_description_interfaces/srv/GetTypeDescription'
     );
     this._typeDescriptionService = null;
+
+    this._enabled = false;
+    const startTypeDescriptionServiceParam = 'start_type_description_service';
+    if (!node.hasParameter(startTypeDescriptionServiceParam)) {
+      node.declareParameter(
+        new Parameter(
+          startTypeDescriptionServiceParam,
+          ParameterType.PARAMETER_BOOL,
+          true
+        ),
+        new ParameterDescriptor(
+          startTypeDescriptionServiceParam,
+          ParameterType.PARAMETER_BOOL,
+          'If enabled, start the ~/get_type_description service.',
+          true
+        )
+      );
+    }
+    const param = node.getParameter(startTypeDescriptionServiceParam);
+    this._enabled = param.value;
   }
 
   start() {
-    if (this._typeDescriptionService) {
+    if (!this._enabled || this._typeDescriptionService) {
       return;
     }
 

test/test-type-description-service.js

@@ -19,6 +19,7 @@ const assertUtils = require('./utils.js');
 const DistroUtils = require('../lib/distro.js');
 const rclnodejs = require('../index.js');
 const TypeDescriptionService = require('../lib/type_description_service.js');
+const { exec } = require('child_process');
 
 describe('type description service test suite', function () {
   this.timeout(60 * 1000);
@@ -73,4 +74,22 @@ describe('type description service test suite', function () {
       done();
     });
   });
+
+  it('Test type description service configured by parameter', function (done) {
+    exec(
+      'ros2 param list /test_type_description_service',
+      (error, stdout, stderr) => {
+        if (error || stderr) {
+          done(
+            new Error(
+              'Test type description service configured by parameter failed.'
+            )
+          );
+        }
+        if (stdout.includes('start_type_description_service')) {
+          done();
+        }
+      }
+    );
+  });
 });