[FEAT] implemented 3 different kinds of scheduling

 - immediate
 - threaded
 - managed with Celery
(see `gargantext.util.schedule`)

gargantext/models/nodes.py

 from gargantext.util.db import *
 from gargantext.util.files import upload
-from gargantext.util import workflow
 from gargantext.constants import *
 
 from datetime import datetime
@@ -71,5 +70,4 @@ class Node(Base):
         })
         session.add(corpus)
         session.commit()
-        workflow.parse(corpus)
         return corpus

gargantext/util/schedule.py

+"""This module defines three distinct decorators for scheduling.
+"""
+
+def scheduled_now(func):
+    """Provides a decorator to execute the task right away.
+    Mostly useful for debugging purpose.
+    """
+    return func
+
+
+import threading
+def scheduled_thread(func):
+    """Provides a decorator to schedule a task as a new thread.
+    Problem: a shutdown may lose the task forever...
+    """
+    def go(*args, **kwargs):
+        thread = threading.Thread(target=func, args=args, kwargs=kwargs)
+        thread.start()
+    return go
+
+
+
+from celery import shared_task
+def scheduled_celery(func):
+    """Provides a decorator to schedule a task with Celery.
+    """
+    @shared_task
+    def _func(*args, **kwargs):
+        func(*args, **kwargs)
+    def go(*args, **kwargs):
+        _func.apply_async(args=args, kwargs=kwargs)
+    return go
+
+
+# scheduled = scheduled_now
+# scheduled = scheduled_thread
+scheduled = scheduled_celery

gargantext/util/workflow.py

-from celery import shared_task
+from gargantext.util.db import *
+from gargantext.models import *
+from gargantext.util.schedule import scheduled
+
 from time import sleep
 
 
-@shared_task
-def _parse(corpus_id):
-    print('ABOUT TO PARSE CORPUS #%d' % corpus_id)
+@scheduled
+def parse(corpus_id):
+    print('CORPUS #%d...' % (corpus_id, ))
+    corpus = session.query(Node).filter(Node.id == corpus_id).first()
     sleep(2)
-    print('PARSED CORPUS #%d' % corpus_id)
-
-
-def parse(corpus):
-    print('ABOUT TO PLAN PARSING')
-    _parse.apply_async((corpus.id,),)
-    print('PLANNED PARSING')
+    if corpus is None:
+        print('NO SUCH CORPUS: #%d' % corpus_id)
+        return
+    print('CORPUS #%d: %s' % (corpus_id, corpus, ))

gargantext/views/pages/projects.py

+from gargantext.util import workflow
 from gargantext.util.http import *
 from gargantext.util.db import *
 from gargantext.util.db_cache import cache
@@ -85,6 +86,7 @@ def project(request, project_id):
             resource_type = request.POST['type'],
             resource_upload = request.FILES['file'],
         )
+        workflow.parse(corpus.id)
 
     # corpora within this project
     corpora = project.children('CORPUS').all()