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Building a Module

Start/Stop the Odoo server

Odoo uses a client/server architecture in which clients are web browsers accessing the Odoo server via RPC.

Business logic and extension is generally performed on the server side, although supporting client features (e.g. new data representation such as interactive maps) can be added to the client.

In order to start the server, simply invoke the command odoo-bin in the shell, adding the full path to the file if necessary:


The server is stopped by hitting Ctrl-C twice from the terminal, or by killing the corresponding OS process.

Build an Odoo module

Both server and client extensions are packaged as modules which are optionally loaded in a database.

Odoo modules can either add brand new business logic to an Odoo system, or alter and extend existing business logic: a module can be created to add your country's accounting rules to Odoo's generic accounting support, while the next module adds support for real-time visualisation of a bus fleet.

Everything in Odoo thus starts and ends with modules.

Composition of a module

An Odoo module can contain a number of elements:

Business objects
Declared as Python classes, these resources are automatically persisted by Odoo based on their configuration
Data files
XML or CSV files declaring metadata (views or reports), configuration data (modules parameterization), demonstration data and more
Web controllers
Handle requests from web browsers
Static web data
Images, CSS or javascript files used by the web interface or website

Module structure

Each module is a directory within a module directory. Module directories are specified by using the --addons-path option.

An Odoo module is declared by its manifest. See the manifest documentation about it.

A module is also a Python package with a file, containing import instructions for various Python files in the module.

For instance, if the module has a single file might contain:

from . import mymodule

Odoo provides a mechanism to help set up a new module, odoo-bin has a subcommand scaffold to create an empty module:

$ odoo-bin scaffold <module name> <where to put it>

The command creates a subdirectory for your module, and automatically creates a bunch of standard files for a module. Most of them simply contain commented code or XML. The usage of most of those files will be explained along this tutorial.

Object-Relational Mapping

A key component of Odoo is the ORM layer. This layer avoids having to write most SQL by hand and provides extensibility and security services2.

Business objects are declared as Python classes extending Model which integrates them into the automated persistence system.

Models can be configured by setting a number of attributes at their definition. The most important attribute is _name which is required and defines the name for the model in the Odoo system. Here is a minimally complete definition of a model:

from odoo import models
class MinimalModel(models.Model):
    _name = 'test.model'

Model fields

Fields are used to define what the model can store and where. Fields are defined as attributes on the model class:

from odoo import models, fields

class LessMinimalModel(models.Model):
    _name = 'test.model2'

    name = fields.Char()

Common Attributes

Much like the model itself, its fields can be configured, by passing configuration attributes as parameters:

name = field.Char(required=True)

Some attributes are available on all fields, here are the most common ones:

string (unicode, default: field's name)
The label of the field in UI (visible by users).
required (bool, default: False)
If True, the field can not be empty, it must either have a default value or always be given a value when creating a record.
help (unicode, default: '')
Long-form, provides a help tooltip to users in the UI.
index (bool, default: False)
Requests that Odoo create a database index on the column.

Simple fields

There are two broad categories of fields: "simple" fields which are atomic values stored directly in the model's table and "relational" fields linking records (of the same model or of different models).

Example of simple fields are Boolean, Date, Char.

Reserved fields

Odoo creates a few fields in all models1. These fields are managed by the system and shouldn't be written to. They can be read if useful or necessary:

id (Id)
The unique identifier for a record in its model.
create_date (Datetime)
Creation date of the record.
create_uid (Many2one)
User who created the record.
write_date (Datetime)
Last modification date of the record.
write_uid (Many2one)
user who last modified the record.

Special fields

By default, Odoo also requires a name field on all models for various display and search behaviors. The field used for these purposes can be overridden by setting _rec_name.

Data files

Odoo is a highly data driven system. Although behavior is customized using Python code part of a module's value is in the data it sets up when loaded.

Module data is declared via data files, XML files with <record> elements. Each <record> element creates or updates a database record.


        <record model="{model name}" id="{record identifier}">
            <field name="{a field name}">{a value}</field>

  • model is the name of the Odoo model for the record.
  • id is an external identifier, it allows referring to the record (without having to know its in-database identifier).
  • <field> elements have a name which is the name of the field in the model (e.g. description). Their body is the field's value.

Data files have to be declared in the manifest file to be loaded, they can be declared in the 'data' list (always loaded) or in the 'demo' list (only loaded in demonstration mode).

Actions and Menus

Actions and menus are regular records in database, usually declared through data files. Actions can be triggered in three ways:

  1. by clicking on menu items (linked to specific actions)
  2. by clicking on buttons in views (if these are connected to actions)
  3. as contextual actions on object

Because menus are somewhat complex to declare there is a <menuitem> shortcut to declare an and connect it to the corresponding action more easily.

<record model="ir.actions.act_window" id="action_list_ideas">
    <field name="name">Ideas</field>
    <field name="res_model">idea.idea</field>
    <field name="view_mode">tree,form</field>
<menuitem id="menu_ideas" parent="menu_root" name="Ideas" sequence="10"

Basic views

Views define the way the records of a model are displayed. Each type of view represents a mode of visualization (a list of records, a graph of their aggregation, …). Views can either be requested generically via their type (e.g. a list of partners) or specifically via their id. For generic requests, the view with the correct type and the lowest priority will be used (so the lowest-priority view of each type is the default view for that type).

View inheritance allows altering views declared elsewhere (adding or removing content).

Generic view declaration

A view is declared as a record of the model ir.ui.view. The view type is implied by the root element of the arch field:

<record model="ir.ui.view" id="view_id">
    <field name="name"></field>
    <field name="model">object_name</field>
    <field name="priority" eval="16"/>
    <field name="arch" type="xml">
        <!-- view content: <form>, <tree>, <graph>, ... -->

Tree views

Tree views, also called list views, display records in a tabular form.

Their root element is <tree>. The simplest form of the tree view simply lists all the fields to display in the table (each field as a column):

<tree string="Idea list">
    <field name="name"/>
    <field name="inventor_id"/>

Form views

Forms are used to create and edit single records.

Their root element is <form>. They are composed of high-level structure elements (groups, notebooks) and interactive elements (buttons and fields):

<form string="Idea form">
    <group colspan="4">
        <group colspan="2" col="2">
            <separator string="General stuff" colspan="2"/>
            <field name="name"/>
            <field name="inventor_id"/>

        <group colspan="2" col="2">
            <separator string="Dates" colspan="2"/>
            <field name="active"/>
            <field name="invent_date" readonly="1"/>

        <notebook colspan="4">
            <page string="Description">
                <field name="description" nolabel="1"/>

        <field name="state"/>

Form views can also use plain HTML for more flexible layouts:

<form string="Idea Form">
        <button string="Confirm" type="object" name="action_confirm"
                states="draft" class="oe_highlight" />
        <button string="Mark as done" type="object" name="action_done"
                states="confirmed" class="oe_highlight"/>
        <button string="Reset to draft" type="object" name="action_draft"
                states="confirmed,done" />
        <field name="state" widget="statusbar"/>
        <div class="oe_title">
            <label for="name" class="oe_edit_only" string="Idea Name" />
            <h1><field name="name" /></h1>
        <separator string="General" colspan="2" />
        <group colspan="2" col="2">
            <field name="description" placeholder="Idea description..." />

Search views

Search views customize the search field associated with the list view (and other aggregated views). Their root element is <search> and they're composed of fields defining which fields can be searched on:

    <field name="name"/>
    <field name="inventor_id"/>

If no search view exists for the model, Odoo generates one which only allows searching on the name field.

Relations between models

A record from a model may be related to a record from another model. For instance, a sale order record is related to a client record that contains the client data; it is also related to its sale order line records.

Relational fields

Relational fields link records, either of the same model (hierarchies) or between different models.

Relational field types are:

Many2one(other_model, ondelete='set null')

A simple link to an other object:

One2many(other_model, related_field)

A virtual relationship, inverse of a Many2one. A One2many behaves as a container of records, accessing it results in a (possibly empty) set of records:

for other in foo.other_ids:

Bidirectional multiple relationship, any record on one side can be related to any number of records on the other side. Behaves as a container of records, accessing it also results in a possibly empty set of records:

for other in foo.other_ids:


Model inheritance

Odoo provides two inheritance mechanisms to extend an existing model in a modular way.

The first inheritance mechanism allows a module to modify the behavior of a model defined in another module:

  • add fields to a model,
  • override the definition of fields on a model,
  • add constraints to a model,
  • add methods to a model,
  • override existing methods on a model.

The second inheritance mechanism (delegation) allows to link every record of a model to a record in a parent model, and provides transparent access to the fields of the parent record.

View inheritance

Instead of modifying existing views in place (by overwriting them), Odoo provides view inheritance where children "extension" views are applied on top of root views, and can add or remove content from their parent.

An extension view references its parent using the inherit_id field, and instead of a single view its arch field is composed of any number of xpath elements selecting and altering the content of their parent view:

<!-- improved idea categories list -->
<record id="idea_category_list2" model="ir.ui.view">
    <field name="name">id.category.list2</field>
    <field name="model">idea.category</field>
    <field name="inherit_id" ref="id_category_list"/>
    <field name="arch" type="xml">
        <!-- find field description and add the field
             idea_ids after it -->
        <xpath expr="//field[@name='description']" position="after">
          <field name="idea_ids" string="Number of ideas"/>
An XPath expression selecting a single element in the parent view. Raises an error if it matches no element or more than one

Operation to apply to the matched element:

appends xpath's body at the end of the matched element
replaces the matched element with the xpath's body, replacing any $0 node occurrence in the new body with the original element
inserts the xpath's body as a sibling before the matched element
inserts the xpaths's body as a sibling after the matched element
alters the attributes of the matched element using special attribute elements in the xpath's body


In Odoo, Domains are values that encode conditions on records. A domain is a list of criteria used to select a subset of a model's records. Each criteria is a triple with a field name, an operator and a value.

For instance, when used on the Product model the following domain selects all services with a unit price over 1000:

[('product_type', '=', 'service'), ('unit_price', '>', 1000)]

By default criteria are combined with an implicit AND. The logical operators & (AND), | (OR) and ! (NOT) can be used to explicitly combine criteria. They are used in prefix position (the operator is inserted before its arguments rather than between). For instance to select products "which are services OR have a unit price which is NOT between 1000 and 2000":

    ('product_type', '=', 'service'),
    '!', '&',
        ('unit_price', '>=', 1000),
        ('unit_price', '<', 2000)]

A domain parameter can be added to relational fields to limit valid records for the relation when trying to select records in the client interface.

Computed fields and default values

So far fields have been stored directly in and retrieved directly from the database. Fields can also be computed. In that case, the field's value is not retrieved from the database but computed on-the-fly by calling a method of the model.

To create a computed field, create a field and set its attribute compute to the name of a method. The computation method should simply set the value of the field to compute on every record in self.

import random
from odoo import models, fields, api

class ComputedModel(models.Model):
    _name = 'test.computed'

    name = fields.Char(compute='_compute_name')

    def _compute_name(self):
        for record in self:
   = str(random.randint(1, 1e6))


The value of a computed field usually depends on the values of other fields on the computed record. The ORM expects the developer to specify those dependencies on the compute method with the decorator depends(). The given dependencies are used by the ORM to trigger the recomputation of the field whenever some of its dependencies have been modified:

from odoo import models, fields, api

class ComputedModel(models.Model):
    _name = 'test.computed'

    name = fields.Char(compute='_compute_name')
    value = fields.Integer()

    def _compute_name(self):
        for record in self:
   = "Record with value %s" % record.value

Default values

Any field can be given a default value. In the field definition, add the option default=X where X is either a Python literal value (boolean, integer, float, string), or a function taking a recordset and returning a value:

name = fields.Char(default="Unknown")
user_id = fields.Many2one('res.users', default=lambda self: self.env.user)


The "onchange" mechanism provides a way for the client interface to update a form whenever the user has filled in a value in a field, without saving anything to the database.

For instance, suppose a model has three fields amount, unit_price and price, and you want to update the price on the form when any of the other fields is modified. To achieve this, define a method where self represents the record in the form view, and decorate it with onchange() to specify on which field it has to be triggered. Any change you make on self will be reflected on the form.

<!-- content of form view -->
<field name="amount"/>
<field name="unit_price"/>
<field name="price" readonly="1"/>
# onchange handler
@api.onchange('amount', 'unit_price')
def _onchange_price(self):
    # set auto-changing field
    self.price = self.amount * self.unit_price
    # Can optionally return a warning and domains
    return {
        'warning': {
            'title': "Something bad happened",
            'message': "It was very bad indeed",

For computed fields, valued onchange behavior is built-in as can be seen by playing with the Session form: change the number of seats or participants, and the taken_seats progressbar is automatically updated.

Model constraints

Odoo provides two ways to set up automatically verified invariants: Python constraints and SQL constraints.

A Python constraint is defined as a method decorated with constrains(), and invoked on a recordset. The decorator specifies which fields are involved in the constraint, so that the constraint is automatically evaluated when one of them is modified. The method is expected to raise an exception if its invariant is not satisfied:

from odoo.exceptions import ValidationError

def _check_something(self):
    for record in self:
        if record.age > 20:
            raise ValidationError("Your record is too old: %s" % record.age)
    # all records passed the test, don't return anything

SQL constraints are defined through the model attribute _sql_constraints. The latter is assigned to a list of triples of strings (name, sql_definition, message), where name is a valid SQL constraint name, sql_definition is a table_constraint expression, and message is the error message.

Advanced Views

Tree views

Tree views can take supplementary attributes to further customize their behavior:


allow changing the style of a row's text based on the corresponding record's attributes.

Values are Python expressions. For each record, the expression is evaluated with the record's attributes as context values and if true, the corresponding style is applied to the row. Other context values are uid (the id of the current user) and current_date (the current date as a string of the form yyyy-MM-dd).

{$name} can be bf (font-weight: bold), it (font-style: italic), or any bootstrap contextual color (danger, info, muted, primary, success or warning).

<tree string="Idea Categories" decoration-info="state=='draft'"
    <field name="name"/>
    <field name="state"/>
Either "top" or "bottom". Makes the tree view editable in-place (rather than having to go through the form view), the value is the position where new rows appear.


Displays records as calendar events. Their root element is <calendar> and their most common attributes are:

The name of the field used for color segmentation. Colors are automatically distributed to events, but events in the same color segment (records which have the same value for their @color field) will be given the same color.
record's field holding the start date/time for the event
date_stop (optional)
record's field holding the end date/time for the event

field (to define the label for each calendar event)

<calendar string="Ideas" date_start="invent_date" color="inventor_id">
    <field name="name"/>

Search views

Search view <field> elements can have a @filter_domain that overrides the domain generated for searching on the given field. In the given domain, self represents the value entered by the user. In the example below, it is used to search on both fields name and description.

Search views can also contain <filter> elements, which act as toggles for predefined searches. Filters must have one of the following attributes:

add the given domain to the current search
add some context to the current search; use the key group_by to group results on the given field name
<search string="Ideas">
    <field name="name"/>
    <field name="description" string="Name and description"
           filter_domain="['|', ('name', 'ilike', self), ('description', 'ilike', self)]"/>
    <field name="inventor_id"/>
    <field name="country_id" widget="selection"/>

    <filter name="my_ideas" string="My Ideas"
            domain="[('inventor_id', '=', uid)]"/>
    <group string="Group By">
        <filter name="group_by_inventor" string="Inventor"
                context="{'group_by': 'inventor_id'}"/>

To use a non-default search view in an action, it should be linked using the search_view_id field of the action record.

The action can also set default values for search fields through its context field: context keys of the form search_default_field_name will initialize field_name with the provided value. Search filters must have an optional @name to have a default and behave as booleans (they can only be enabled by default).


Horizontal bar charts typically used to show project planning and advancement, their root element is <gantt>.

<gantt string="Ideas"
       default_group_by="inventor_id" />

Graph views

Graph views allow aggregated overview and analysis of models, their root element is <graph>.

Graph views have 4 display modes, the default mode is selected using the @type attribute.

Bar (default)

a bar chart, the first dimension is used to define groups on the horizontal axis, other dimensions define aggregated bars within each group.

By default bars are side-by-side, they can be stacked by using @stacked="True" on the <graph>

2-dimensional line chart
2-dimensional pie

Graph views contain <field> with a mandatory @type attribute taking the values:

row (default)
the field should be aggregated by default
the field should be aggregated rather than grouped on
<graph string="Total idea score by Inventor">
    <field name="inventor_id"/>
    <field name="score" type="measure"/>


Used to organize tasks, production processes, etc… their root element is <kanban>.

A kanban view shows a set of cards possibly grouped in columns. Each card represents a record, and each column the values of an aggregation field.

For instance, project tasks may be organized by stage (each column is a stage), or by responsible (each column is a user), and so on.

Kanban views define the structure of each card as a mix of form elements (including basic HTML) and QWeb.


Access control mechanisms must be configured to achieve a coherent security policy.

Group-based access control mechanisms

Groups are created as normal records on the model res.groups, and granted menu access via menu definitions. However even without a menu, objects may still be accessible indirectly, so actual object-level permissions (read, write, create, unlink) must be defined for groups. They are usually inserted via CSV files inside modules. It is also possible to restrict access to specific fields on a view or object using the field's groups attribute.

Access rights

Access rights are defined as records of the model ir.model.access. Each access right is associated to a model, a group (or no group for global access), and a set of permissions: read, write, create, unlink. Such access rights are usually created by a CSV file named after its model: ir.model.access.csv.


Record rules

A record rule restricts the access rights to a subset of records of the given model. A rule is a record of the model ir.rule, and is associated to a model, a number of groups (many2many field), permissions to which the restriction applies, and a domain. The domain specifies to which records the access rights are limited.

Here is an example of a rule that prevents the deletion of leads that are not in state cancel. Notice that the value of the field groups must follow the same convention as the method write() of the ORM.

<record id="delete_cancelled_only" model="ir.rule">
    <field name="name">Only cancelled leads may be deleted</field>
    <field name="model_id" ref="crm.model_crm_lead"/>
    <field name="groups" eval="[(4, ref('sales_team.group_sale_manager'))]"/>
    <field name="perm_read" eval="0"/>
    <field name="perm_write" eval="0"/>
    <field name="perm_create" eval="0"/>
    <field name="perm_unlink" eval="1" />
    <field name="domain_force">[('state','=','cancel')]</field>


Wizards describe interactive sessions with the user (or dialog boxes) through dynamic forms. A wizard is simply a model that extends the class TransientModel instead of Model. The class TransientModel extends Model and reuse all its existing mechanisms, with the following particularities:

  • Wizard records are not meant to be persistent; they are automatically deleted from the database after a certain time. This is why they are called transient.
  • Wizard models do not require explicit access rights: users have all permissions on wizard records.
  • Wizard records may refer to regular records or wizard records through many2one fields, but regular records cannot refer to wizard records through a many2one field.

We want to create a wizard that allow users to create attendees for a particular session, or for a list of sessions at once.

Launching wizards

Wizards are launched by ir.actions.act_window records, with the field target set to the value new. The latter opens the wizard view into a popup window. The action may be triggered by a menu item.

There is another way to launch the wizard: using an ir.actions.act_window record like above, but with an extra field src_model that specifies in the context of which model the action is available. The wizard will appear in the contextual actions of the model, above the main view. Because of some internal hooks in the ORM, such an action is declared in XML with the tag act_window.

<act_window id="launch_the_wizard"
            name="Launch the Wizard"

Wizards use regular views and their buttons may use the attribute special="cancel" to close the wizard window without saving.


Each module can provide its own translations within the i18n directory, by having files named LANG.po where LANG is the locale code for the language, or the language and country combination when they differ (e.g. pt.po or pt_BR.po). Translations will be loaded automatically by Odoo for all enabled languages. Developers always use English when creating a module, then export the module terms using Odoo's gettext POT export feature (Settings ‣ Translations ‣ Import/Export ‣ Export Translation without specifying a language), to create the module template POT file, and then derive the translated PO files. Many IDE's have plugins or modes for editing and merging PO/POT files.

|- idea/ # The module directory
   |- i18n/ # Translation files
      | - idea.pot # Translation Template (exported from Odoo)
      | - fr.po # French translation
      | - pt_BR.po # Brazilian Portuguese translation
      | (...)


Printed reports

Odoo 11.0 uses a report engine based on QWeb, Twitter Bootstrap and Wkhtmltopdf.

A report is a combination two elements:

  • an, for which a <report> shortcut element is provided, it sets up various basic parameters for the report (default type, whether the report should be saved to the database after generation,…)

        attachment="(object.state in ('open','paid')) and
            ('INV'+(object.number or '').replace('/','')+'.pdf')"
  • A standard QWeb view for the actual report:

    <t t-call="web.html_container">
        <t t-foreach="docs" t-as="o">
            <t t-call="web.external_layout">
                <div class="page">
                    <h2>Report title</h2>
    the standard rendering context provides a number of elements, the most
    important being:
        the records for which the report is printed
        the user printing the report

Because reports are standard web pages, they are available through a URL and output parameters can be manipulated through this URL, for instance the HTML version of the Invoice report is available through http://localhost:8069/report/html/account.report_invoice/1 (if account is installed) and the PDF version through http://localhost:8069/report/pdf/account.report_invoice/1.



The web-service module offer a common interface for all web-services :


Business objects can also be accessed via the distributed object mechanism. They can all be modified via the client interface with contextual views.

Odoo is accessible through XML-RPC/JSON-RPC interfaces, for which libraries exist in many languages.

XML-RPC Library

The following example is a Python 3 program that interacts with an Odoo server with the library xmlrpc.client:

import xmlrpc.client

root = 'http://%s:%d/xmlrpc/' % (HOST, PORT)

uid = xmlrpc.client.ServerProxy(root + 'common').login(DB, USER, PASS)
print("Logged in as %s (uid: %d)" % (USER, uid))

# Create a new note
sock = xmlrpc.client.ServerProxy(root + 'object')
args = {
    'color' : 8,
    'memo' : 'This is a note',
    'create_uid': uid,
note_id = sock.execute(DB, uid, PASS, 'note.note', 'create', args)

JSON-RPC Library

The following example is a Python 3 program that interacts with an Odoo server with the standard Python libraries urllib.request and json:

import json
import random
import urllib.request

def json_rpc(url, method, params):
    data = {
        "jsonrpc": "2.0",
        "method": method,
        "params": params,
        "id": random.randint(0, 1000000000),
    req = urllib.request.Request(url=url, data=json.dumps(data).encode(), headers={
    reply = json.load(urllib.request.urlopen(req))
    if reply.get("error"):
        raise Exception(reply["error"])
    return reply["result"]

def call(url, service, method, *args):
    return json_rpc(url, "call", {"service": service, "method": method, "args": args})

# log in the given database
url = "http://%s:%s/jsonrpc" % (HOST, PORT)
uid = call(url, "common", "login", DB, USER, PASS)

# create a new note
args = {
    'color': 8,
    'memo': 'This is another note',
    'create_uid': uid,
note_id = call(url, "object", "execute", DB, uid, PASS, 'note.note', 'create', args)

Examples can be easily adapted from XML-RPC to JSON-RPC.

[2] writing raw SQL queries is possible, but requires care as it bypasses all Odoo authentication and security mechanisms.