feat: Add functions.completeError and functions.completeSuccess (#1328)

Completion of #1301

- Adds the new complete functions for the Function Execution Event
- Adds the context version of those methods

---
> this PR to handle event
[function_executed](https://api.slack.com/events/function_executed) and
response the function with
[functions.completeSuccess](https://api.slack.com/methods/functions.completeSuccess)
and
[functions.completeError](https://api.slack.com/methods/functions.completeError)

---------

Co-authored-by: Yoga Setiawan <yogainformatika@gmail.com>

examples/function/function.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"fmt"
+	"github.com/slack-go/slack"
+	"github.com/slack-go/slack/slackevents"
+	"github.com/slack-go/slack/socketmode"
+	"os"
+)
+
+func main() {
+	api := slack.New(
+		os.Getenv("SLACK_BOT_TOKEN"),
+		slack.OptionDebug(true),
+		slack.OptionAppLevelToken(os.Getenv("SLACK_APP_TOKEN")),
+	)
+	client := socketmode.New(api, socketmode.OptionDebug(true))
+
+	go func() {
+		for evt := range client.Events {
+			switch evt.Type {
+			case socketmode.EventTypeEventsAPI:
+				eventsAPIEvent, ok := evt.Data.(slackevents.EventsAPIEvent)
+				if !ok {
+					fmt.Printf("Ignored %+v\n", evt)
+					continue
+				}
+
+				fmt.Printf("Event received: %+v\n", eventsAPIEvent)
+				client.Ack(*evt.Request)
+
+				switch eventsAPIEvent.Type {
+				case slackevents.CallbackEvent:
+					innerEvent := eventsAPIEvent.InnerEvent
+					switch ev := innerEvent.Data.(type) {
+					case *slackevents.FunctionExecutedEvent:
+						callbackID := ev.Function.CallbackID
+						if callbackID == "sample_function" {
+							userId := ev.Inputs["user_id"]
+							payload := map[string]string{
+								"user_id": userId,
+							}
+
+							err := api.FunctionCompleteSuccess(ev.FunctionExecutionID, slack.FunctionCompleteSuccessRequestOptionOutput(payload))
+							if err != nil {
+								fmt.Printf("failed posting message: %v \n", err)
+							}
+						}
+					}
+				default:
+					client.Debugf("unsupported Events API event received\n")
+				}
+
+			default:
+				fmt.Fprintf(os.Stderr, "Unexpected event type received: %s\n", evt.Type)
+			}
+		}
+	}()
+	client.Run()
+}

examples/function/manifest.json

@@ -0,0 +1,56 @@
+{
+  "display_information": {
+    "name": "Function Example"
+  },
+  "features": {
+    "app_home": {
+      "home_tab_enabled": false,
+      "messages_tab_enabled": true,
+      "messages_tab_read_only_enabled": true
+    },
+    "bot_user": {
+      "display_name": "Function Example",
+      "always_online": true
+    }
+  },
+  "oauth_config": {
+    "scopes": {
+      "bot": [
+        "chat:write"
+      ]
+    }
+  },
+  "settings": {
+    "interactivity": {
+      "is_enabled": true
+    },
+    "org_deploy_enabled": true,
+    "socket_mode_enabled": true,
+    "token_rotation_enabled": false
+  },
+  "functions": {
+    "sample_function": {
+      "title": "Sample function",
+      "description": "Runs sample function",
+      "input_parameters": {
+        "user_id": {
+          "type": "slack#/types/user_id",
+          "title": "User",
+          "description": "Message recipient",
+          "is_required": true,
+          "hint": "Select a user in the workspace",
+          "name": "user_id"
+        }
+      },
+      "output_parameters": {
+        "user_id": {
+          "type": "slack#/types/user_id",
+          "title": "User",
+          "description": "User that completed the function",
+          "is_required": true,
+          "name": "user_id"
+        }
+      }
+    }
+  }
+}

function_execute.go

@@ -0,0 +1,93 @@
+package slack
+
+import (
+	"context"
+	"encoding/json"
+)
+
+type (
+	FunctionCompleteSuccessRequest struct {
+		FunctionExecutionID string            `json:"function_execution_id"`
+		Outputs             map[string]string `json:"outputs"`
+	}
+
+	FunctionCompleteErrorRequest struct {
+		FunctionExecutionID string `json:"function_execution_id"`
+		Error               string `json:"error"`
+	}
+)
+
+type FunctionCompleteSuccessRequestOption func(opt *FunctionCompleteSuccessRequest) error
+
+func FunctionCompleteSuccessRequestOptionOutput(outputs map[string]string) FunctionCompleteSuccessRequestOption {
+	return func(opt *FunctionCompleteSuccessRequest) error {
+		if len(outputs) > 0 {
+			opt.Outputs = outputs
+		}
+		return nil
+	}
+}
+
+// FunctionCompleteSuccess indicates function is completed
+func (api *Client) FunctionCompleteSuccess(functionExecutionId string, options ...FunctionCompleteSuccessRequestOption) error {
+	return api.FunctionCompleteSuccessContext(context.Background(), functionExecutionId, options...)
+}
+
+// FunctionCompleteSuccess indicates function is completed
+func (api *Client) FunctionCompleteSuccessContext(ctx context.Context, functionExecutionId string, options ...FunctionCompleteSuccessRequestOption) error {
+	// More information: https://api.slack.com/methods/functions.completeSuccess
+	r := &FunctionCompleteSuccessRequest{
+		FunctionExecutionID: functionExecutionId,
+	}
+	for _, option := range options {
+		option(r)
+	}
+
+	endpoint := api.endpoint + "functions.completeSuccess"
+	jsonData, err := json.Marshal(r)
+	if err != nil {
+		return err
+	}
+
+	response := &SlackResponse{}
+	if err := postJSON(ctx, api.httpclient, endpoint, api.token, jsonData, response, api); err != nil {
+		return err
+	}
+
+	if !response.Ok {
+		return response.Err()
+	}
+
+	return nil
+}
+
+// FunctionCompleteError indicates function is completed with error
+func (api *Client) FunctionCompleteError(functionExecutionID string, errorMessage string) error {
+	return api.FunctionCompleteErrorContext(context.Background(), functionExecutionID, errorMessage)
+}
+
+// FunctionCompleteErrorContext indicates function is completed with error
+func (api *Client) FunctionCompleteErrorContext(ctx context.Context, functionExecutionID string, errorMessage string) error {
+	// More information: https://api.slack.com/methods/functions.completeError
+	r := FunctionCompleteErrorRequest{
+		FunctionExecutionID: functionExecutionID,
+	}
+	r.Error = errorMessage
+
+	endpoint := api.endpoint + "functions.completeError"
+	jsonData, err := json.Marshal(r)
+	if err != nil {
+		return err
+	}
+
+	response := &SlackResponse{}
+	if err := postJSON(ctx, api.httpclient, endpoint, api.token, jsonData, response, api); err != nil {
+		return err
+	}
+
+	if !response.Ok {
+		return response.Err()
+	}
+
+	return nil
+}

function_execute_test.go

@@ -0,0 +1,80 @@
+package slack
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+	"net/http"
+	"testing"
+)
+
+func postHandler(t *testing.T) func(rw http.ResponseWriter, r *http.Request) {
+	return func(rw http.ResponseWriter, r *http.Request) {
+		body, err := io.ReadAll(r.Body)
+		defer r.Body.Close()
+		if err != nil {
+			t.Error(err)
+			return
+		}
+
+		var req FunctionCompleteSuccessRequest
+		err = json.Unmarshal(body, &req)
+		if err != nil {
+			t.Error(err)
+			return
+		}
+
+		switch req.FunctionExecutionID {
+		case "function-success":
+			postSuccess(rw, r)
+		case "function-failure":
+			postFailure(rw, r)
+		}
+	}
+}
+
+func postSuccess(rw http.ResponseWriter, r *http.Request) {
+	rw.Header().Set("Content-Type", "application/json")
+	response := []byte(`{
+    "ok": true
+	}`)
+	rw.Write(response)
+}
+
+func postFailure(rw http.ResponseWriter, r *http.Request) {
+	rw.Header().Set("Content-Type", "application/json")
+	response := []byte(`{
+			"ok": false,
+			"error": "function_execution_not_found"
+	}`)
+	rw.Write(response)
+	rw.WriteHeader(500)
+}
+
+func TestFunctionComplete(t *testing.T) {
+	http.HandleFunc("/functions.completeSuccess", postHandler(t))
+
+	once.Do(startServer)
+
+	api := New("testing-token", OptionAPIURL("http://"+serverAddr+"/"))
+
+	err := api.FunctionCompleteSuccess("function-success")
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = api.FunctionCompleteSuccess("function-failure")
+	if err == nil {
+		t.Fail()
+	}
+
+	err = api.FunctionCompleteSuccessContext(context.Background(), "function-success")
+	if err != nil {
+		t.Error(err)
+	}
+
+	err = api.FunctionCompleteSuccessContext(context.Background(), "function-failure")
+	if err == nil {
+		t.Fail()
+	}
+}