[IMP] Make possible to make sql queries on an external database

sql_request_abstract/__init__.py

@@ -1 +1,2 @@
 from . import models
+from . import sql_db

sql_request_abstract/models/sql_request_mixin.py

@@ -12,8 +12,10 @@ from io import BytesIO
 from psycopg2 import ProgrammingError
 from psycopg2.sql import SQL
 
-from odoo import _, api, fields, models
-from odoo.exceptions import UserError
+from odoo import _, api, fields, models, tools
+from odoo.exceptions import UserError, ValidationError
+
+from ..sql_db import get_external_cursor
 
 logger = logging.getLogger(__name__)
 
@@ -96,6 +98,26 @@ class SQLRequestMixin(models.AbstractModel):
         column2="user_id",
         default=_default_user_ids,
     )
+    use_external_database = fields.Boolean(
+        help=(
+            "If filled, the query will be executed against an external "
+            "database, configured in Odoo main configuration file. "
+        )
+    )
+
+    @api.constrains("use_external_database")
+    def check_external_config(self):
+        external_db_records = self.filtered(lambda rec: rec.use_external_database)
+        if external_db_records:
+            external_db_name = tools.config.get("external_db_name")
+            if not external_db_name:
+                raise ValidationError(
+                    _(
+                        "You can't use an external database as there are no such "
+                        "configuration about this. Please contact your Odoo administrator"
+                        " to solve this issue."
+                    )
+                )
 
     has_group_changed = fields.Boolean(
         copy=False,
@@ -202,42 +224,54 @@ class SQLRequestMixin(models.AbstractModel):
         else:
             raise UserError(_("Unimplemented mode : '%s'") % mode)
 
+        query_cr = self._get_cr_for_query()
+
         if rollback:
-            rollback_name = self._create_savepoint()
+            rollback_name = self._create_savepoint(query_cr)
         try:
             if mode == "stdout":
                 output = BytesIO()
-                self.env.cr.copy_expert(query, output)
+                query_cr.copy_expert(query, output)
                 res = base64.b64encode(output.getvalue())
                 output.close()
             else:
-                self.env.cr.execute(query)
+                query_cr.execute(query)
                 if mode == "fetchall":
-                    res = self.env.cr.fetchall()
+                    res = query_cr.fetchall()
                     if header:
                         colnames = [desc[0] for desc in self.env.cr.description]
                         res.insert(0, colnames)
                 elif mode == "fetchone":
-                    res = self.env.cr.fetchone()
+                    res = query_cr.fetchone()
         finally:
-            self._rollback_savepoint(rollback_name)
+            self._rollback_savepoint(rollback_name, query_cr)
 
         return res
 
     # Private Section
+    def _get_cr_for_query(self):
+        self.ensure_one()
+        if self.use_external_database:
+            return get_external_cursor()
+        else:
+            return self.env.cr
+
     @api.model
-    def _create_savepoint(self):
+    def _create_savepoint(self, cr):
         rollback_name = "{}_{}".format(self._name.replace(".", "_"), uuid.uuid1().hex)
         # pylint: disable=sql-injection
         req = "SAVEPOINT %s" % (rollback_name)
-        self.env.cr.execute(req)
+        cr.execute(req)
         return rollback_name
 
     @api.model
-    def _rollback_savepoint(self, rollback_name):
+    def _rollback_savepoint(self, rollback_name, cr):
         # pylint: disable=sql-injection
         req = "ROLLBACK TO SAVEPOINT %s" % (rollback_name)
-        self.env.cr.execute(req)
+        cr.execute(req)
+        # close external database cursor
+        if self.env.cr != cr:
+            cr.close()
 
     @api.model
     def _check_materialized_view_available(self):

sql_request_abstract/readme/CONFIGURE.rst

@@ -0,0 +1,6 @@
+To configure the use of an external database, you need to edit the main configuration file of your instance and add the external database configuration with following keys :
+* external_db_user
+* external_db_password
+* external_db_name
+* external_db_host
+* external_db_port

sql_request_abstract/sql_db.py

@@ -0,0 +1,22 @@
+# License LGPL-3.0 or later (http://www.gnu.org/licenses/lgpl.html).
+
+from odoo import tools
+from odoo.sql_db import Connection, ConnectionPool, _Pool  # noqa
+
+
+def connection_info_for_external_database():
+    db_name = tools.config.get("external_db_name")
+    connection_info = {"database": db_name}
+    for p in ("host", "port", "user", "password"):
+        cfg = tools.config.get("external_db_" + p)
+        if cfg:
+            connection_info[p] = cfg
+    return db_name, connection_info
+
+
+def get_external_cursor():
+    global _Pool
+    if _Pool is None:
+        _Pool = ConnectionPool(int(tools.config["db_maxconn"]))
+    db, info = connection_info_for_external_database()
+    return Connection(_Pool, db, info).cursor()