dev: add command to list extensions

This commit adds the `extension:list` command for listing extensions.
This command is itself defined in an extension. To make this possible,
an event called 'create.commands' is emitted form CommandService with
the event object holding a function that can be used to add commands.

extensions/extension-util.js

@@ -0,0 +1,32 @@
+//@extension name extension
+const { Context } = extension.import('core');
+
+// The 'create.commands' event is fired by CommandService
+extension.on('create.commands', event => {
+
+    // Add command to list available extensions
+    event.createCommand('list', {
+        description: 'list available extensions',
+        handler: async (_, console) => {
+
+            // Get extnsion information from context
+            const extensionInfos = Context.get('extensionInfo');
+
+            // Iterate over extension infos
+            for ( const info of Object.values(extensionInfos) ) {
+
+                // Construct a string
+                const moduleType = info.type === 'module'
+                    ? '\x1B[32;1m(ESM)\x1B[0m'
+                    : '\x1B[33;1m(CJS)\x1B[0m';
+                let str = `- ${info.name} ${moduleType}`;
+                if ( info.priority !== 0 ) {
+                    str += ` (priority ${info.priority})`;
+                }
+
+                // Print a string
+                console.log(str);
+            }
+        },
+    });
+});

src/backend/src/ExtensionService.js

@@ -95,19 +95,19 @@ class ExtensionService extends BaseService {
         svc_event.on_all(async (key, data, meta = {}) => {
             meta.from_outside_of_extension = true;
 
-            const promises = [];
-            
-            // push event to the extension's event bus
-            promises.push(
-                this.state.extension.emit(key, data, meta));
-
-            // legacy: older extensions prefix "core." to events from Puter
-            promises.push(
-                this.state.extension.emit(`core.${key}`, data, meta));
-                
-            // future: going to remove 'boot.' prefix from lifecycle events
-
-            await Promise.all(promises);
+            await Context.sub({
+                extension_name: this.state.extension.name,
+            }).arun(async () => {
+                const promises = [
+                    // push event to the extension's event bus
+                    this.state.extension.emit(key, data, meta),
+                    // legacy: older extensions prefix "core." to events from Puter
+                    this.state.extension.emit(`core.${key}`, data, meta),
+                ];
+                // await this.state.extension.emit(key, data, meta);
+                await Promise.all(promises);
+            });
+            // await Promise.all(promises);
         });
 
         // Propagate all events from extension to Puter's event bus

src/backend/src/Kernel.js

@@ -51,6 +51,7 @@ class Kernel extends AdvancedBase {
 
         this.entry_path = entry_path;
         this.extensionExports = {};
+        this.extensionInfo = {};
         this.registry = {};
         
         this.runtimeModuleRegistry = new RuntimeModuleRegistry();
@@ -126,6 +127,7 @@ class Kernel extends AdvancedBase {
             config,
             logger: this.bootLogger,
             extensionExports: this.extensionExports,
+            extensionInfo: this.extensionInfo,
             registry: this.registry,
             args,
             ['runtime-modules']: this.runtimeModuleRegistry,
@@ -447,6 +449,11 @@ class Kernel extends AdvancedBase {
         
         const extension_name = exportObject?.name ?? packageJSON.name;
         this.extensionExports[extension_name] = exportObject;
+        this.extensionInfo[extension_name] = {
+            name: extension_name,
+            priority: mod_entry.priority,
+            type: packageJSON?.type ?? 'commonjs',
+        };
         mod.extension.registry = this.registry;
         mod.extension.name = extension_name;
         

src/backend/src/services/CommandService.js

@@ -17,6 +17,7 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
+const { Context } = require("../util/context");
 const BaseService = require("./BaseService");
 
 
@@ -100,6 +101,30 @@ class CommandService extends BaseService {
             }
         }));
     }
+    
+    async ['__on_boot.consolidation'] () {
+        const svc_event = this.services.get('event');
+        const svc_command = this;
+        const event = {
+            createCommand (name, command) {
+                const serviceName = Context.get('extension_name') ?? '%missing%';
+                const commandSpec = typeof command === 'function'
+                    ? { handler: command }
+                    : command;
+                if ( typeof commandSpec !== 'object' ) {
+                    throw new Error('command must be either a function or an object');
+                }
+                if ( ! (typeof command.handler === 'function') ) {
+                    throw new Error('command should have a handler function');
+                }
+                svc_command.registerCommands(serviceName, [{
+                    id: name,
+                    ...commandSpec,
+                }]);
+            },
+        };
+        svc_event.emit('create.commands', event);
+    }
 
     registerCommands(serviceName, commands) {
         if ( ! this.log ) process.exit(1);