docs: adding missing step on setting up the custom scaffolder action

Signed-off-by: Tiago Barbosa <tbarbos@hotmail.com>

docs/advanced/create-service-software-template.md

@@ -14,6 +14,54 @@ yarn add --cwd packages/backend @pagerduty/backstage-plugin-backend @pagerduty/b
 
 1. This command adds `@pagerduty/backstage-plugin-backend` and `@pagerduty/backstage-plugin-common` packages to the `packages/backend` folder because it is a backend plugin.
 
+## Adding the custom action to the project
+
+Backstage Scaffolder capabilities can be extended with custom actions that support Software Templates. For that to happen you need to update `packages/backend/src/plugins/scaffolder.ts` and add custom actions.
+
+Now, the list of scaffolder actions cannot be appended so you need re-create it and append your custom action. Otherwise all actions will be replaced just with yours.
+
+```typescript
+// Add imports
+import { createBuiltinActions } from '@backstage/plugin-scaffolder-backend';
+import { ScmIntegrations } from '@backstage/integration';
+import { createPagerDutyServiceAction } from '@pagerduty/backstage-plugin-backend';
+
+export default async function createPlugin(
+ env: PluginEnvironment,
+): Promise<Router> {
+
+ ...
+
+ // Pull integrations
+ const integrations = ScmIntegrations.fromConfig(env.config);
+
+ // Rebuild built-in actions
+ const builtInActions = createBuiltinActions({
+ integrations,
+ catalogClient,
+ config: env.config,
+ reader: env.reader,
+ });
+
+ // Append PagerDuty custom action to the list
+ const actions = [...builtInActions, createPagerDutyServiceAction()];
+
+ // Add new action list to the scaffolder
+ return await createRouter({
+ actions, // this is the only update needed on this list
+ logger: env.logger,
+ config: env.config,
+ database: env.database,
+ reader: env.reader,
+ catalogClient,
+ identity: env.identity,
+ permissions: env.permissions,
+ });
+}
+```
+
+This step registers the custom action with the Scaffolder and allows it to be used in the Software template which you will configure on next step.
+
 ## Adding the custom action to a Software Template
 
 Software Templates can be simple or complex depending on the practices you are trying to standardize across your teams. Here, we provide a simple example of a template that requests basic information for a Backstage service and augments that with information relevant for creating the service in PagerDuty.