Add a server environment mixin

To automatically convert fields into fields reading values from the
environment. Until now, every module reimplements the same computed
field.

server_environment/__init__.py

@@ -17,4 +17,5 @@
 #    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 ##############################################################################
+from . import models
 from .serv_config import serv_config, setboolean

server_environment/models/__init__.py

@@ -0,0 +1 @@
+from . import server_env_mixin

server_environment/models/server_env_mixin.py

@@ -0,0 +1,112 @@
+# Copyright 2018 Camptocamp (https://www.camptocamp.com).
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+import logging
+
+from odoo import api, models
+from ..serv_config import serv_config
+
+_logger = logging.getLogger(__name__)
+
+
+class ServerEnvMixin(models.AbstractModel):
+    """Mixin to add server environment in existing models
+
+    Usage::
+
+        class StorageBackend(models.Model):
+            _name = "storage.backend"
+            _inherit = ["storage.backend", "server.env.mixin"]
+
+            @property
+            def _server_env_fields(self):
+                return {"directory_path": 'get'}
+
+    With the snippet above, the "storage.backend" model will now use a server
+    environment configuration for the field ``directory_path``.
+
+    Under the hood, this mixin will automatically replaces the original field
+    by a computed field that reads from the configuration files.
+
+    By default, it will look for the configuration in a section named
+    ``[model_name.Record Name]`` where ``model_name`` is the ``_name`` of the
+    model with ``.`` replaced by ``_``. It can be customized by overriding the
+    method :meth:`~server_env_section_name`.
+    """
+    _name = 'server.env.mixin'
+
+    @property
+    def _server_env_fields(self):
+        """Dict of fields to replace by fields computed from env
+
+        To override in models. The dictionary is:
+        {'name_of_the_field': 'name_of_the_configparser_getter'}
+
+        The configparser getter can be one of: get, getbool, getint
+
+        Example::
+
+            @property
+            def _server_env_fields(self):
+                base_fields = super()._server_env_fields
+                sftp_fields = {
+                    "sftp_server": "get",
+                    "sftp_port": "getint",
+                    "sftp_login": "get",
+                    "sftp_password": "get",
+                }
+                sftp_fields.update(base_fields)
+                return sftp_fields
+        """
+        return {}
+
+    @api.multi
+    def _server_env_section_name(self):
+        """Name of the section in the configuration files
+
+        Can be customized in your model
+        """
+        self.ensure_one()
+        return ".".join(
+            (self._name.replace(".", "_"), self.name)
+        )
+
+    @api.multi
+    def _server_env_read_from_config(self, section_name, field_name,
+                                     config_getter):
+        self.ensure_one()
+        try:
+            getter = getattr(serv_config, config_getter)
+            value = getter(section_name, field_name)
+        except:
+            _logger.exception(
+                "error trying to read field %s in section %s",
+                field_name,
+                section_name,
+            )
+            return False
+        return value
+
+    @api.multi
+    def _compute_server_env(self):
+        for record in self:
+            for field_name, getter_name in self._server_env_fields.items():
+                section_name = self._server_env_section_name()
+                value = self._server_env_read_from_config(
+                    section_name, field_name, getter_name
+                )
+                record[field_name] = value
+
+    def _server_env_transform_field_to_read_from_env(self, field):
+        """Transform the original field in a computed field"""
+        field.compute = '_compute_server_env'
+        field.store = False
+        field.copy = False
+        field.sparse = None
+
+    @api.model
+    def _setup_base(self):
+        super()._setup_base()
+        for fieldname in self._server_env_fields:
+            field = self._fields[fieldname]
+            self._server_env_transform_field_to_read_from_env(field)