adding log for api failure and tidy up error type

server/api.go

@@ -35,6 +35,7 @@ func (p *Plugin) MattermostAuthorizationRequired(next http.Handler) http.Handler
 
 func (p *Plugin) HelloWorld(w http.ResponseWriter, r *http.Request) {
 	if _, err := w.Write([]byte("Hello, world!")); err != nil {
+		p.API.LogError("Failed to write response", "error", err)
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 	}
 }

server/command/command.go

@@ -13,7 +13,7 @@ type Handler struct {
 }
 
 type Command interface {
-	Handle(args *model.CommandArgs) (*model.CommandResponse, *model.AppError)
+	Handle(args *model.CommandArgs) (*model.CommandResponse, error)
 	executeHelloCommand(args *model.CommandArgs) *model.CommandResponse
 }
 
@@ -36,7 +36,7 @@ func NewCommandHandler(client *pluginapi.Client) Command {
 }
 
 // ExecuteCommand hook calls this method to execute the commands that were registered in the NewCommandHandler function.
-func (c *Handler) Handle(args *model.CommandArgs) (*model.CommandResponse, *model.AppError) {
+func (c *Handler) Handle(args *model.CommandArgs) (*model.CommandResponse, error) {
 	trigger := strings.TrimPrefix(strings.Fields(args.Command)[0], "/")
 	switch trigger {
 	case helloCommandTrigger:

server/plugin.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"net/http"
 	"sync"
 	"time"
 
@@ -71,7 +72,11 @@ func (p *Plugin) OnDeactivate() error {
 
 // This will execute the commands that were registered in the NewCommandHandler function.
 func (p *Plugin) ExecuteCommand(c *plugin.Context, args *model.CommandArgs) (*model.CommandResponse, *model.AppError) {
-	return p.commandClient.Handle(args)
+	response, err := p.commandClient.Handle(args)
+	if err != nil {
+		return nil, model.NewAppError("ExecuteCommand", "plugin.command.execute_command.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	return response, nil
 }
 
 // See https://developers.mattermost.com/extend/plugins/server/reference/