fixed server/celery error handlers

goodtablesio/app.py

@@ -1,4 +1,5 @@
 import logging
+import sqlalchemy
 from flask import Flask, render_template
 
 from goodtablesio import settings
@@ -46,7 +47,7 @@ def server_error(err):
     return (render_template('error500.html'), 500)
 
 
-@app.errorhandler(Exception)
+@app.errorhandler(sqlalchemy.exc.SQLAlchemyError)
 def error_handler(err):
     # To prevent session from break because of unhandled error with no rollback
     # https://github.com/frictionlessdata/goodtables.io/issues/97

goodtablesio/blueprints/api.py

@@ -33,6 +33,9 @@ def record_params(setup_state):
 
 @api.app_errorhandler(Exception)
 def handle_api_errors(error):
+    # TODO: this is not really correct way to catch blueprint errors
+    # because flask doesn't support error handlers per blueprint
+    # so this error handler is global for the whole app
     if api.debug:
         raise error
     if not isinstance(error, APIError):

goodtablesio/signals.py

@@ -1,4 +1,5 @@
 import logging
+import sqlalchemy
 from celery import signals
 from goodtablesio.utils.database import create_session
 from goodtablesio.services import database
@@ -21,7 +22,9 @@ def shutdown_worker(**kwargs):
 
 @signals.task_failure.connect
 def task_failure(**kwargs):
-    # To prevent session from break because of unhandled error with no rollback
-    # https://github.com/frictionlessdata/goodtables.io/issues/97
-    log.info('Database session rollback by celery error handler')
-    database['session'].rollback()
+    exception = kwargs['exception']
+    if isinstance(exception, sqlalchemy.exc.SQLAlchemyError):
+        # To prevent session from break because of unhandled error with no rollback
+        # https://github.com/frictionlessdata/goodtables.io/issues/97
+        log.info('Database session rollback by celery error handler')
+        database['session'].rollback()