#57: Improved error message when migration command fails.

Makefile

@@ -14,8 +14,9 @@ help:
 
 clean:
 	@echo "Cleaning..."
-	@git clean -df > /dev/null
 	@rm -rf build dist src/simple_db_migrate.egg-info simple_db_migrate.egg-info *.pyc **/*.pyc *~ *.migration *.foo
+	# removing test temp files
+	@rm -rf `date +%Y`*
 
 compile: clean
 	@echo "Compiling source code..."

src/core/exceptions.py

@@ -0,0 +1,13 @@
+class MigrationException(Exception):
+    def __init__(self, msg=None, sql=None):
+        self.msg = msg
+        if not msg:
+            self.msg = 'error executing migration'
+        self.sql = sql
+
+    def __str__(self):
+        if self.sql:
+            self.details = '[ERROR DETAILS] SQL command was:\n%s' % self.sql
+            return '%s\n\n%s' % (self.msg, self.details)
+
+        return self.msg

src/mysql.py

@@ -3,6 +3,7 @@
 
 import MySQLdb
 
+from core.exceptions import MigrationException
 from helpers import Utils
 
 class MySQL(object):
@@ -32,20 +33,22 @@ def __mysql_connect(self, connect_using_db_name=True):
                 conn.select_db(self.__mysql_db)
             return conn
         except Exception, e:
-            raise Exception("could not connect to database (%s)" % e)
+            raise Exception("could not connect to database: %s" % e)
 
     def __execute(self, sql):
         db = self.__mysql_connect()        
         cursor = db.cursor()
         cursor._defer_warnings = True
+        curr_statement = None
         try:
             for statement in self._parse_sql_statements(sql):
+                curr_statement = statement
                 cursor.execute(statement.encode("utf-8"))
             cursor.close()        
             db.commit()
             db.close()
         except Exception, e:
-            raise Exception("error executing migration (%s)" % e)
+            raise MigrationException("error executing migration: %s" % e, curr_statement)
 
     def __change_db_version(self, version, up=True):
         if up: