Import / export of the dashboards. (apache#1197)

* Implement import / export dashboard functionality.

* Address comments from discussion.

* Add function descriptions.

* Minor fixes

* Fix tests for python 3.

* Export datasources.

* Implement tables import.

* Json.loads does not support trailing commas.

* Improve alter_dict func

* Resolve comments.

* Refactor tests

* Move params_dict and alter_params to the ImportMixin

* Fix flask menues.

caravel/__init__.py

@@ -82,6 +82,12 @@ def checkout(dbapi_con, con_record, con_proxy):
 if app.config.get('ENABLE_PROXY_FIX'):
     app.wsgi_app = ProxyFix(app.wsgi_app)
 
+if app.config.get('UPLOAD_FOLDER'):
+    try:
+        os.makedirs(app.config.get('UPLOAD_FOLDER'))
+    except OSError:
+        pass
+
 
 class MyIndexView(IndexView):
     @expose('/')

caravel/data/__init__.py

@@ -1058,7 +1058,7 @@ def load_multiformat_time_series_data():
         'string0': ['%Y-%m-%d %H:%M:%S.%f', None],
         'string3': ['%Y/%m/%d%H:%M:%S.%f', None],
     }
-    for col in obj.table_columns:
+    for col in obj.columns:
         dttm_and_expr = dttm_and_expr_dict[col.column_name]
         col.python_date_format = dttm_and_expr[0]
         col.dbatabase_expr = dttm_and_expr[1]
@@ -1069,7 +1069,7 @@ def load_multiformat_time_series_data():
     tbl = obj
 
     print("Creating some slices")
-    for i, col in enumerate(tbl.table_columns):
+    for i, col in enumerate(tbl.columns):
         slice_data = {
             "granularity_sqla": col.column_name,
             "datasource_id": "8",

caravel/migrations/versions/b46fa1b0b39e_add_params_to_tables.py

@@ -0,0 +1,28 @@
+"""Add json_metadata to the tables table.
+
+Revision ID: b46fa1b0b39e
+Revises: ef8843b41dac
+Create Date: 2016-10-05 11:30:31.748238
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'b46fa1b0b39e'
+down_revision = 'ef8843b41dac'
+
+from alembic import op
+import logging
+import sqlalchemy as sa
+
+
+def upgrade():
+    op.add_column('tables',
+                  sa.Column('params', sa.Text(), nullable=True))
+
+
+def downgrade():
+    try:
+        op.drop_column('tables', 'params')
+    except Exception as e:
+        logging.warning(str(e))
+