Add rerun command snippet in "show error" modal (#3117)

* add re-run command snippet to show error modal

To facilitate quick re-run of failed tasks this commit adds a text
snippet to the "Show error" modal in the task visualiser. The scheduler
api call was modified to include the extra information needed to create
call command.

* use JSON.stringify and remove `=` in cmd string

* ensure all underscores are replaced with hyphens

luigi/scheduler.py

@@ -1560,7 +1560,9 @@ def re_enable_task(self, task_id):
     def fetch_error(self, task_id, **kwargs):
         if self._state.has_task(task_id):
             task = self._state.get_task(task_id)
-            return {"taskId": task_id, "error": task.expl, 'displayName': task.pretty_id}
+            return {"taskId": task_id, "error": task.expl, 'displayName':
+                    task.pretty_id, 'taskParams': task.params, 'taskModule':
+                    task.module, 'taskFamily': task.family}
         else:
             return {"taskId": task_id, "error": ""}
 

luigi/static/visualiser/index.html

@@ -54,6 +54,8 @@ <h4 class="modal-title" id="myModalLabel">Traceback for {{displayName}}</h4>
               </div>
               <div class="modal-body">
                 <pre class="pre-scrollable">{{error}}</pre>
+                Command to re-run:
+                <pre class="pre-scrollable">luigi --module {{taskModule}} {{taskFamily}} {{taskParams}}</pre>
               </div>
               <div class="modal-footer">
                 <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>

luigi/static/visualiser/js/visualiserApp.js

@@ -325,6 +325,9 @@ function visualiserApp(luigi) {
 
     function showErrorTrace(data) {
         data.error = decodeError(data.error);
+        if (data.taskParams) {
+          data.taskParams = Object.entries(data.taskParams).map(([k,v]) => `--${k.replace(/_/g, '-')} ${JSON.stringify(v)}`).join(" ");
+        }
         $("#errorModal").empty().append(renderTemplate("errorTemplate", data));
         $("#errorModal").modal({});
     }