API Docs: Custom steps documentation

docs/content/guides/bolt-basics.md

@@ -31,19 +31,20 @@ Here is the list of the available methods to dispatch events.
 
 |Method|Constraints (value: type)|Description|
 |-|-|-|
-|`app.event`|event type: `Class\<Event\>`|[Events API](/guides/events-api): Responds to any kinds of bot/user events you subscribe.|
-|`app.message`|keyword: `String` \| `Pattern`|[Events API](/guides/events-api): Responds to messages posted by a user only when the text in messages matches the given keyword or regular expressions.|
-|`app.command`|command name: `String` \| `Pattern`|[Slash Commands](/guides/slash-commands): Responds to slash command invocations in the workspace.|
+|`app.attachmentAction`|callback_id: `String` \| `Pattern`|Legacy Messaging: Responds to user actions in attachments. These events can be triggered in only messages.|
 |`app.blockAction`|action_id: `String` \| `Pattern`|[Interactive Components](/guides/interactive-components): Responds to user actions (e.g., click a button, choose an item from select menus, radio buttons, etc.) in `blocks`. These events can be triggered in all the surfaces (messages, modals, and Home tabs).|
 |`app.blockSuggestion`|action_id: `String` \| `Pattern`|[Interactive Components](/guides/interactive-components): Responds to user actions to input a keyword (the length needs to be the `min_query_length` or longer) in select menus (external data source).|
-|`app.viewSubmission`|callback_id: `String` \| `Pattern`|[Modals](/guides/modals): Responds to data submissions in modals.|
-|`app.viewClosed`|callback_id: `String` \| `Pattern`|[Modals](/guides/modals): Responds to the events where users close modals by clicking Cancel buttons. The `notify_on_close` has to be `true` when opening/pushing the modal.|
-|`app.globalShortcut`|callback_id: `String` \| `Pattern`|[Shortcuts](/guides/shortcuts): Responds to global shortcut invocations.|
-|`app.messageShortcut`|callback_id: `String` \| `Pattern`|[Shortcuts](/guides/shortcuts): Responds to shortcut invocations in message menus.|
+|`app.command`|command name: `String` \| `Pattern`|[Slash Commands](/guides/slash-commands): Responds to slash command invocations in the workspace.|
+|`app.dialogCancellation`|callback_id `String` \| `Pattern`|Dialogs: Responds to the events where users close dialogs by clicking Cancel buttons.|
 |`app.dialogSubmission`|callback_id: `String` \| `Pattern`|Dialogs: Responds to data submissions in dialogs.|
 |`app.dialogSuggestion`|callback_id: `String` \| `Pattern`|Dialogs: Responds to requests to load options for `"external"` typed select menus in dialogs.|
-|`app.dialogCancellation`|callback_id `String` \| `Pattern`|Dialogs: Responds to the events where users close dialogs by clicking Cancel buttons.|
-|`app.attachmentAction`|callback_id: `String` \| `Pattern`|Legacy Messaging: Responds to user actions in attachments. These events can be triggered in only messages.|
+|`app.event`|event type: `Class\<Event\>`|[Events API](/guides/events-api): Responds to any kinds of bot/user events you subscribe.|
+| `app.function` | callback_id: `String` \| `Pattern` | [Custom steps](/guides/custom-steps): Defines a function that can be used as a custom step in [Workflow Builder](https://slack.com/help/articles/360035692513-Guide-to-Slack-Workflow-Builder).
+|`app.globalShortcut`|callback_id: `String` \| `Pattern`|[Shortcuts](/guides/shortcuts): Responds to global shortcut invocations.|
+|`app.message`|keyword: `String` \| `Pattern`|[Events API](/guides/events-api): Responds to messages posted by a user only when the text in messages matches the given keyword or regular expressions.|
+|`app.messageShortcut`|callback_id: `String` \| `Pattern`|[Shortcuts](/guides/shortcuts): Responds to shortcut invocations in message menus.|
+|`app.viewClosed`|callback_id: `String` \| `Pattern`|[Modals](/guides/modals): Responds to the events where users close modals by clicking Cancel buttons. The `notify_on_close` has to be `true` when opening/pushing the modal.|
+|`app.viewSubmission`|callback_id: `String` \| `Pattern`|[Modals](/guides/modals): Responds to data submissions in modals.|
 
 ---
 ## Development Guides by Feature

docs/content/guides/custom-steps.md

@@ -0,0 +1,77 @@
+---
+title: Custom Steps
+lang: en
+---
+
+Your app can use the `function()` method to listen to incoming [custom step requests](https://docs.slack.dev/workflows/workflow-steps). Custom steps are used in Workflow Builder to build workflows. The method requires a step `callback_id` of type `string`. This `callback_id` must also be defined in your [Function](https://docs.slack.dev/reference/app-manifest#functions) definition. Custom steps must be finalized using the `complete()` or `fail()` listener arguments to notify Slack that your app has processed the request.
+
+* `complete()` requires one argument: an `outputs` object. It ends your custom step successfully and provides an object containing the outputs of your custom step as per its definition.
+* `fail()` requires one argument: `error` of type `string`. It ends your custom step unsuccessfully and provides a message containing information regarding why your custom step failed.
+
+You can reference your custom step's inputs using the `getInputs()` method shown below.
+
+```java
+app.function("sample_function", (req, ctx) -> {
+  app.executorService().submit(() -> {
+    try {
+      String userId = req.getEvent().getInputs().get("user_id").asString();
+      ChatPostMessageResponse response = ctx.client().chatPostMessage(r -> r
+        .channel(userId) // sending a DM
+        .text("Hi! Thank you for submitting the request! We'll let you know once the processing completes.")
+      );
+      Map<String, Object> outputs = new HashMap<String, Object>();
+      outputs.put("channel_id", response.getChannel());
+      outputs.put("ts", response.getTs());
+      ctx.complete(outputs);
+    } catch (Exception e) {
+      ctx.logger.error(e.getMessage(), e);
+      try {
+        ctx.fail("Failed to handle 'sample_function' custom step execution (error: " + e.getMessage() + ")");
+      } catch (Exception ex) {
+        ctx.logger.error(e.getMessage(), e);
+      }
+    }
+  });
+  return ctx.ack();
+});
+```
+
+The corresponding function definition section of the app manifest for the preceding function might look like this:
+
+```json
+...
+"functions": {
+    "sample_function": {
+        "title": "Send a request",
+        "description": "Send some request to the backend",
+        "input_parameters": {
+            "user_id": {
+                "type": "slack#/types/user_id",
+                "title": "User",
+                "description": "Who to send it",
+                "is_required": true,
+                "hint": "Select a user in the workspace",
+                "name": "user_id"
+            }
+        },
+        "output_parameters": {
+            "channel_id": {
+                "type": "slack#/types/channel_id",
+                "title": "DM ID",
+                "description": "The DM ID",
+                "is_required": true,
+                "name": "channel_id"
+            },
+            "ts": {
+                "type": "string",
+                "title": "Message timestamp",
+                "description": "Sent message timestamp",
+                "is_required": true,
+                "name": "ts"
+            }
+        }
+    }
+}
+```
+
+Once your custom step is defined in your app's manifest and implemented in code, it is discoverable in Workflow Builder when you **Add Step** and search for the title of your step or name of your app.

docs/sidebars.js

@@ -36,6 +36,7 @@ const sidebars = {
 					items: ['guides/interactive-components', 'guides/modals', 'guides/app-home',],
 				},  
         'guides/ai-apps',
+        'guides/custom-steps',
         'guides/shortcuts',
         'guides/slash-commands',
         {