Adding extra options to deeper configure sqlalchemy

caravel/migrations/versions/867bf4f117f9_adding_extra_field_to_database_model.py

@@ -0,0 +1,22 @@
+"""Adding extra field to Database model
+
+Revision ID: 867bf4f117f9
+Revises: fee7b758c130
+Create Date: 2016-04-03 15:23:20.280841
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '867bf4f117f9'
+down_revision = 'fee7b758c130'
+
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    op.add_column('dbs', sa.Column('extra', sa.Text(), nullable=True))
+
+
+def downgrade():
+    op.drop_column('dbs', 'extra')

caravel/models.py

@@ -9,6 +9,7 @@
 from six import string_types
 import sqlparse
 import requests
+import textwrap
 
 from dateutil.parser import parse
 from flask import flash, request, g
@@ -292,12 +293,20 @@ class Database(Model, AuditMixinNullable):
     sqlalchemy_uri = Column(String(1024))
     password = Column(EncryptedType(String(1024), config.get('SECRET_KEY')))
     cache_timeout = Column(Integer)
+    extra = Column(Text, default=textwrap.dedent("""\
+    {
+        "metadata_params": {},
+        "engine_params": {},
+    }
+    """))
 
     def __repr__(self):
         return self.database_name
 
     def get_sqla_engine(self):
-        return create_engine(self.sqlalchemy_uri_decrypted)
+        extra = self.get_extra()
+        params = extra.get('engine_params', {})
+        return create_engine(self.sqlalchemy_uri_decrypted, **params)
 
     def safe_sqlalchemy_uri(self):
         return self.sqlalchemy_uri
@@ -336,8 +345,18 @@ def grains(self):
     def grains_dict(self):
         return {grain.name: grain for grain in self.grains()}
 
+    def get_extra(self):
+        extra = {}
+        if self.extra:
+            try:
+                extra = json.loads(self.extra)
+            except Exception as e:
+                logging.error(e)
+        return extra
+
     def get_table(self, table_name):
-        meta = MetaData()
+        extra = self.get_extra()
+        meta = MetaData(**extra.get('metadata_params', {}))
         return Table(
             table_name, meta,
             autoload=True,

caravel/utils.py

@@ -10,6 +10,7 @@
 from sqlalchemy.types import TypeDecorator, TEXT
 from markdown import markdown as md
 import parsedatetime
+from flask import Markup
 from flask_appbuilder.security.sqla import models as ab_models
 
 
@@ -241,13 +242,16 @@ def json_iso_dttm_ser(obj):
     return obj
 
 
-def markdown(s):
+def markdown(s, markup_wrap=False):
     s = s or ''
-    return md(s, [
+    s = md(s, [
         'markdown.extensions.tables',
         'markdown.extensions.fenced_code',
         'markdown.extensions.codehilite',
     ])
+    if markup_wrap:
+        s = Markup(s)
+    return s
 
 
 def readfile(filepath):

caravel/views.py

@@ -117,7 +117,8 @@ class DatabaseView(CaravelModelView, DeleteMixin):  # noqa
     datamodel = SQLAInterface(models.Database)
     list_columns = ['database_name', 'sql_link', 'created_by_', 'changed_on']
     order_columns = utils.list_minus(list_columns, ['created_by_'])
-    add_columns = ['database_name', 'sqlalchemy_uri', 'cache_timeout']
+    add_columns = [
+        'database_name', 'sqlalchemy_uri', 'cache_timeout', 'extra']
     search_exclude_columns = ('password',)
     edit_columns = add_columns
     add_template = "caravel/models/database/add.html"
@@ -127,7 +128,16 @@ class DatabaseView(CaravelModelView, DeleteMixin):  # noqa
         'sqlalchemy_uri': (
             "Refer to the SqlAlchemy docs for more information on how "
             "to structure your URI here: "
-            "http://docs.sqlalchemy.org/en/rel_1_0/core/engines.html")
+            "http://docs.sqlalchemy.org/en/rel_1_0/core/engines.html"),
+        'extra': utils.markdown(
+            "JSON string containing extra configuration elements. "
+            "The ``engine_params`` object gets unpacked into the "
+            "[sqlalchemy.create_engine]"
+            "(http://docs.sqlalchemy.org/en/latest/core/engines.html#"
+            "sqlalchemy.create_engine) call, while the ``metadata_params`` "
+            "gets unpacked into the [sqlalchemy.MetaData]"
+            "(http://docs.sqlalchemy.org/en/rel_1_0/core/metadata.html"
+            "#sqlalchemy.schema.MetaData) call. ", True),
     }
 
     def pre_add(self, db):