Remove unnecessary content

Signed-off-by: Taras <tarasm@gmail.com>

docs/features/software-templates/writing-templates.md

@@ -581,96 +581,3 @@ output things. You can grab that output using `steps.$stepId.output.$property`.
 You can read more about all the `inputs` and `outputs` defined in the actions in
 code part of the `JSONSchema`, or you can read more about our
 [built in actions](./builtin-actions.md).
-
-## Creating reusable templates
-
-We can use the PlaceholderProcessor to create reusable portions of a template. A placeholder is a property on an entity object that starts with `$`. Backstage has some built in placeholders including `$text`, `$json` and `$yaml`. Each placeholder has a resolver. A resolver is an asyncronous function that receives the value assigned to the placeholder. A resolver is expected to return a promise that resolves to a value. The resolved value will replace the object where the placeholder was defined.
-
-Let's say we want to reuse a portion of the template that asks user to specify a host name and we want to be able to add other fields to that form step.
-
-```yaml
-apiVersion: scaffolder.backstage.io/v1beta3
-kind: Template
-metadata:
-  name: v1beta3-demo
-  title: Microservice example
-  description: scaffolder v1beta3 template demo
-spec:
-  owner: backstage/techdocs-core
-  type: service
-  parameters:
-    - title: Specify a host
-      parameters:
-        name:
-          title: Hostname
-          type: string
-          description: Specify host name
-```
-
-Our placeholder is going to be called `$specifyHostname`. We'd use it like this,
-
-```yaml
-apiVersion: scaffolder.backstage.io/v1beta3
-kind: Template
-metadata:
-  name: v1beta3-demo
-  title: Microservice example
-  description: scaffolder v1beta3 template demo
-spec:
-  owner: backstage/techdocs-core
-  type: service
-  parameters:
-    - $specifyHostname:
-      domainExt:
-        name: Domain extension
-        type: string
-        description: Specify domain extension like .com, .ca, .co.uk or something else.
-```
-
-The result after the placeholder is applied will look like this,
-
-```yaml
-apiVersion: scaffolder.backstage.io/v1beta3
-kind: Template
-metadata:
-  name: v1beta3-demo
-  title: Microservice example
-  description: scaffolder v1beta3 template demo
-spec:
-  owner: backstage/techdocs-core
-  type: service
-  parameters:
-    - title: Specify a host
-      parameters:
-        name:
-          title: Hostname
-          type: string
-          description: Specify host name
-        domainExt:
-          name: Domain extension
-          type: string
-          description: Specify domain extension like .com, .ca, .co.uk or something else.
-```
-
-To implement this, you have to modify the catalog plugin to create a `specifyHostname` resolver. In `/packages/backend/src/plugins/catalog.ts`. Add the following code,
-
-```ts
-const builder = await CatalogBuilder.create(env);
-
-builder.setPlaceholderResolver(
-    'specifyHostname',
-    async specifyHostnameResolver({ value }) => {
-      return {
-        "title": "Specify a host",
-        "parameters": {
-            "name": {
-                "title": "Hostname",
-                "type": "string",
-                "description": "Specify host name"
-            },
-            ...value
-        }
-      }
-    },
-  );`
-```

plugins/catalog-backend/src/modules/core/PlaceholderProcessor.ts

@@ -119,11 +119,6 @@ export class PlaceholderProcessor implements CatalogProcessor {
         return [data, false];
       }
 
-      // if (typeof resolverValue !== 'string') {
-      // treat it as an argument to resolver function
-      // TODO: make this recursive, but it should resolve from bottom up
-      // }
-
       const read = async (url: string): Promise<Buffer> => {
         if (this.options.reader.readUrl) {
           const response = await this.options.reader.readUrl(url);