Overview

Machines

InvenTree has a builtin machine registry. There are different machine types available where each type can have different drivers. Drivers and even custom machine types can be provided by plugins.

Registry

The machine registry is the main component which gets initialized on server start and manages all configured machines.

Initialization process

The machine registry initialization process can be divided into three stages:

• Stage 1: Discover machine types: by looking for classes that inherit the BaseMachineType class
• Stage 2: Discover drivers: by looking for classes that inherit the BaseDriver class (and are not referenced as base driver for any discovered machine type)
• Stage 3: Machine loading:
  1. For each MachineConfig in database instantiate the MachineType class (drivers get instantiated here as needed and passed to the machine class. But only one instance of the driver class is maintained along the registry)
  2. The driver.init_driver function is called for each used driver
  3. The machine.initialize function is called for each machine, which calls the driver.init_machine function for each machine, then the machine.initialized state is set to true

Machine types

Each machine type can provide a different type of connection functionality between inventree and a physical machine. These machine types are already built into InvenTree.

Built-in types

Name	Description
Label printer	Directly print labels for various items.

Example machine type

If you want to create your own machine type, please also take a look at the already existing machine types in machines/machine_types/*.py. The following example creates a machine type called abc.

from django.utils.translation import gettext_lazy as _
from plugin.machine import BaseDriver, BaseMachineType, MachineStatus

class ABCBaseDriver(BaseDriver):
    """Base xyz driver."""

    machine_type = 'abc'

    def my_custom_required_method(self):
        """This function must be overridden."""
        raise NotImplementedError('The `my_custom_required_method` function must be overridden!')

    def my_custom_method(self):
        """This function can be overridden."""
        raise NotImplementedError('The `my_custom_method` function can be overridden!')

    required_overrides = [my_custom_required_method]

class ABCMachine(BaseMachineType):
    SLUG = 'abc'
    NAME = _('ABC')
    DESCRIPTION = _('This is an awesome machine type for ABC.')

    base_driver = ABCBaseDriver

    class ABCStatus(MachineStatus):
        CONNECTED = 100, _('Connected'), 'success'
        STANDBY = 101, _('Standby'), 'success'
        PRINTING = 110, _('Printing'), 'primary'

    MACHINE_STATUS = ABCStatus
    default_machine_status = ABCStatus.DISCONNECTED

Machine Type API

The machine type class gets instantiated for each machine on server startup and the reference is stored in the machine registry. (Therefore machine.NAME is the machine type name and machine.name links to the machine instances user defined name)

Base class for machine types.

Attributes:

Name	Type	Description
SLUG	str	Slug string for identifying the machine type in format /[a-z-]+/ (required)
NAME	str	User friendly name for displaying (required)
DESCRIPTION	str	Description of what this machine type can do (required)
base_driver	type[BaseDriver]	Reference to the base driver for this machine type
MACHINE_SETTINGS	dict[str, SettingsKeyType]	Machine type specific settings dict (optional)
MACHINE_STATUS	type[MachineStatus]	Set of status codes this machine type can have
default_machine_status	MachineStatus	Default machine status with which this machine gets initialized

Source code in InvenTree/machine/machine_type.py

class BaseMachineType(ClassValidationMixin, ClassProviderMixin):
    """Base class for machine types.

    Attributes:
        SLUG: Slug string for identifying the machine type in format /[a-z-]+/ (required)
        NAME: User friendly name for displaying (required)
        DESCRIPTION: Description of what this machine type can do (required)

        base_driver: Reference to the base driver for this machine type

        MACHINE_SETTINGS: Machine type specific settings dict (optional)

        MACHINE_STATUS: Set of status codes this machine type can have
        default_machine_status: Default machine status with which this machine gets initialized
    """

    SLUG: str
    NAME: str
    DESCRIPTION: str

    base_driver: type[BaseDriver]

    MACHINE_SETTINGS: dict[str, SettingsKeyType]

    MACHINE_STATUS: type[MachineStatus]
    default_machine_status: MachineStatus

    # used by the ClassValidationMixin
    required_attributes = [
        'SLUG',
        'NAME',
        'DESCRIPTION',
        'base_driver',
        'MACHINE_STATUS',
        'default_machine_status',
    ]

    def __init__(self, machine_config: MachineConfig) -> None:
        """Base machine type __init__ function."""
        from machine import registry
        from machine.models import MachineSetting

        self.errors: list[Union[str, Exception]] = []
        self.initialized = False

        self.status = self.default_machine_status
        self.status_text: str = ''

        self.pk = machine_config.pk
        self.driver = registry.get_driver_instance(machine_config.driver)

        if not self.driver:
            self.handle_error(f"Driver '{machine_config.driver}' not found")
        if self.driver and not isinstance(self.driver, self.base_driver):
            self.handle_error(
                f"'{self.driver.NAME}' is incompatible with machine type '{self.NAME}'"
            )

        self.machine_settings: dict[str, SettingsKeyType] = getattr(
            self, 'MACHINE_SETTINGS', {}
        )
        self.driver_settings: dict[str, SettingsKeyType] = getattr(
            self.driver, 'MACHINE_SETTINGS', {}
        )

        self.setting_types: list[
            tuple[dict[str, SettingsKeyType], MachineSetting.ConfigType]
        ] = [
            (self.machine_settings, MachineSetting.ConfigType.MACHINE),
            (self.driver_settings, MachineSetting.ConfigType.DRIVER),
        ]

        self.restart_required = False

    def __str__(self):
        """String representation of a machine."""
        return f'{self.name}'

    def __repr__(self):
        """Python representation of a machine."""
        return f'<{self.__class__.__name__}: {self.name}>'

    # --- properties
    @property
    def machine_config(self):
        """Machine_config property which is a reference to the database entry."""
        # always fetch the machine_config if needed to ensure we get the newest reference
        from .models import MachineConfig

        return MachineConfig.objects.get(pk=self.pk)

    @property
    def name(self):
        """The machines name."""
        return self.machine_config.name

    @property
    def active(self):
        """The machines active status."""
        return self.machine_config.active

    # --- hook functions
    def initialize(self):
        """Machine initialization function, gets called after all machines are loaded."""
        if self.driver is None:
            return

        # check if all required settings are defined before continue with init process
        settings_valid, missing_settings = self.check_settings()
        if not settings_valid:
            error_parts = []
            for config_type, missing in missing_settings.items():
                if len(missing) > 0:
                    error_parts.append(
                        f'{config_type.name} settings: ' + ', '.join(missing)
                    )
            self.handle_error(f"Missing {' and '.join(error_parts)}")
            return

        try:
            self.driver.init_machine(self)
            self.initialized = True
        except Exception as e:
            self.handle_error(e)

    def update(self, old_state: dict[str, Any]):
        """Machine update function, gets called if the machine itself changes or their settings.

        Arguments:
            old_state: Dict holding the old machine state before update
        """
        if self.driver is None:
            return

        try:
            self.driver.update_machine(old_state, self)
        except Exception as e:
            self.handle_error(e)

    def restart(self):
        """Machine restart function, can be used to manually restart the machine from the admin ui."""
        if self.driver is None:
            return

        try:
            self.restart_required = False
            self.driver.restart_machine(self)
        except Exception as e:
            self.handle_error(e)

    # --- helper functions
    def handle_error(self, error: Union[Exception, str]):
        """Helper function for capturing errors with the machine.

        Arguments:
            error: Exception or string
        """
        self.errors.append(error)

    def get_setting(
        self, key: str, config_type_str: Literal['M', 'D'], cache: bool = False
    ):
        """Return the 'value' of the setting associated with this machine.

        Arguments:
            key: The 'name' of the setting value to be retrieved
            config_type_str: Either "M" (machine scoped settings) or "D" (driver scoped settings)
            cache: Whether to use RAM cached value (default = False)
        """
        from machine.models import MachineSetting

        config_type = MachineSetting.get_config_type(config_type_str)
        return MachineSetting.get_setting(
            key,
            machine_config=self.machine_config,
            config_type=config_type,
            cache=cache,
        )

    def set_setting(self, key: str, config_type_str: Literal['M', 'D'], value: Any):
        """Set plugin setting value by key.

        Arguments:
            key: The 'name' of the setting to set
            config_type_str: Either "M" (machine scoped settings) or "D" (driver scoped settings)
            value: The 'value' of the setting
        """
        from machine.models import MachineSetting

        config_type = MachineSetting.get_config_type(config_type_str)
        MachineSetting.set_setting(
            key,
            value,
            None,
            machine_config=self.machine_config,
            config_type=config_type,
        )

    def check_settings(self):
        """Check if all required settings for this machine are defined.

        Returns:
            is_valid: Are all required settings defined
            missing_settings: dict[ConfigType, list[str]] of all settings that are missing (empty if is_valid is 'True')
        """
        from machine.models import MachineSetting

        missing_settings: dict[MachineSetting.ConfigType, list[str]] = {}
        for settings, config_type in self.setting_types:
            is_valid, missing = MachineSetting.check_all_settings(
                settings_definition=settings,
                machine_config=self.machine_config,
                config_type=config_type,
            )
            missing_settings[config_type] = missing

        return all(
            len(missing) == 0 for missing in missing_settings.values()
        ), missing_settings

    def set_status(self, status: MachineStatus):
        """Set the machine status code. There are predefined ones for each MachineType.

        Import the MachineType to access it's `MACHINE_STATUS` enum.

        Arguments:
            status: The new MachineStatus code to set
        """
        self.status = status

    def set_status_text(self, status_text: str):
        """Set the machine status text. It can be any arbitrary text.

        Arguments:
            status_text: The new status text to set
        """
        self.status_text = status_text

machine_config property

Machine_config property which is a reference to the database entry.

name property

The machines name.

active property

The machines active status.

initialize()

Machine initialization function, gets called after all machines are loaded.

Source code in InvenTree/machine/machine_type.py

def initialize(self):
    """Machine initialization function, gets called after all machines are loaded."""
    if self.driver is None:
        return

    # check if all required settings are defined before continue with init process
    settings_valid, missing_settings = self.check_settings()
    if not settings_valid:
        error_parts = []
        for config_type, missing in missing_settings.items():
            if len(missing) > 0:
                error_parts.append(
                    f'{config_type.name} settings: ' + ', '.join(missing)
                )
        self.handle_error(f"Missing {' and '.join(error_parts)}")
        return

    try:
        self.driver.init_machine(self)
        self.initialized = True
    except Exception as e:
        self.handle_error(e)

update(old_state)

Machine update function, gets called if the machine itself changes or their settings.

Parameters:

Name	Type	Description	Default
old_state	dict[str, Any]	Dict holding the old machine state before update	required

Source code in InvenTree/machine/machine_type.py

def update(self, old_state: dict[str, Any]):
    """Machine update function, gets called if the machine itself changes or their settings.

    Arguments:
        old_state: Dict holding the old machine state before update
    """
    if self.driver is None:
        return

    try:
        self.driver.update_machine(old_state, self)
    except Exception as e:
        self.handle_error(e)

restart()

Machine restart function, can be used to manually restart the machine from the admin ui.

Source code in InvenTree/machine/machine_type.py

def restart(self):
    """Machine restart function, can be used to manually restart the machine from the admin ui."""
    if self.driver is None:
        return

    try:
        self.restart_required = False
        self.driver.restart_machine(self)
    except Exception as e:
        self.handle_error(e)

handle_error(error)

Helper function for capturing errors with the machine.

Parameters:

Name	Type	Description	Default
error	Union[Exception, str]	Exception or string	required

Source code in InvenTree/machine/machine_type.py

def handle_error(self, error: Union[Exception, str]):
    """Helper function for capturing errors with the machine.

    Arguments:
        error: Exception or string
    """
    self.errors.append(error)

get_setting(key, config_type_str, cache=False)

Return the 'value' of the setting associated with this machine.

Parameters:

Name	Type	Description	Default
key	str	The 'name' of the setting value to be retrieved	required
config_type_str	Literal['M', 'D']	Either "M" (machine scoped settings) or "D" (driver scoped settings)	required
cache	bool	Whether to use RAM cached value (default = False)	False

Source code in InvenTree/machine/machine_type.py

def get_setting(
    self, key: str, config_type_str: Literal['M', 'D'], cache: bool = False
):
    """Return the 'value' of the setting associated with this machine.

    Arguments:
        key: The 'name' of the setting value to be retrieved
        config_type_str: Either "M" (machine scoped settings) or "D" (driver scoped settings)
        cache: Whether to use RAM cached value (default = False)
    """
    from machine.models import MachineSetting

    config_type = MachineSetting.get_config_type(config_type_str)
    return MachineSetting.get_setting(
        key,
        machine_config=self.machine_config,
        config_type=config_type,
        cache=cache,
    )

set_setting(key, config_type_str, value)

Set plugin setting value by key.

Parameters:

Name	Type	Description	Default
key	str	The 'name' of the setting to set	required
config_type_str	Literal['M', 'D']	Either "M" (machine scoped settings) or "D" (driver scoped settings)	required
value	Any	The 'value' of the setting	required

Source code in InvenTree/machine/machine_type.py

def set_setting(self, key: str, config_type_str: Literal['M', 'D'], value: Any):
    """Set plugin setting value by key.

    Arguments:
        key: The 'name' of the setting to set
        config_type_str: Either "M" (machine scoped settings) or "D" (driver scoped settings)
        value: The 'value' of the setting
    """
    from machine.models import MachineSetting

    config_type = MachineSetting.get_config_type(config_type_str)
    MachineSetting.set_setting(
        key,
        value,
        None,
        machine_config=self.machine_config,
        config_type=config_type,
    )

set_status(status)

Set the machine status code. There are predefined ones for each MachineType.

Import the MachineType to access it's MACHINE_STATUS enum.

Parameters:

Name	Type	Description	Default
status	MachineStatus	The new MachineStatus code to set	required

Source code in InvenTree/machine/machine_type.py

def set_status(self, status: MachineStatus):
    """Set the machine status code. There are predefined ones for each MachineType.

    Import the MachineType to access it's `MACHINE_STATUS` enum.

    Arguments:
        status: The new MachineStatus code to set
    """
    self.status = status

set_status_text(status_text)

Set the machine status text. It can be any arbitrary text.

Parameters:

Name	Type	Description	Default
status_text	str	The new status text to set	required

Source code in InvenTree/machine/machine_type.py

def set_status_text(self, status_text: str):
    """Set the machine status text. It can be any arbitrary text.

    Arguments:
        status_text: The new status text to set
    """
    self.status_text = status_text

Drivers

Drivers provide the connection layer between physical machines and inventree. There can be multiple drivers defined for the same machine type. Drivers are provided by plugins that are enabled and extend the corresponding base driver for the particular machine type. Each machine type already provides a base driver that needs to be inherited.

Example driver

A basic driver only needs to specify the basic attributes like SLUG, NAME, DESCRIPTION. The others are given by the used base driver, so take a look at Machine types. The following example will create an driver called abc for the xyz machine type. The class will be discovered if it is provided by an installed & activated plugin just like this:

from plugin import InvenTreePlugin
from plugin.machine.machine_types import ABCBaseDriver

class MyXyzAbcDriverPlugin(InvenTreePlugin):
    NAME = "XyzAbcDriver"
    SLUG = "xyz-driver"
    TITLE = "Xyz Abc Driver"
    # ...

class XYZDriver(ABCBaseDriver):
    SLUG = 'my-xyz-driver'
    NAME = 'My XYZ driver'
    DESCRIPTION = 'This is an awesome XYZ driver for a ABC machine'

Driver API

Base class for all machine drivers.

Attributes:

Name	Type	Description
SLUG	str	Slug string for identifying the driver in format /[a-z-]+/ (required)
NAME	str	User friendly name for displaying (required)
DESCRIPTION	str	Description of what this driver does (required)
MACHINE_SETTINGS	dict[str, SettingsKeyType]	Driver specific settings dict

Source code in InvenTree/machine/machine_type.py

class BaseDriver(ClassValidationMixin, ClassProviderMixin):
    """Base class for all machine drivers.

    Attributes:
        SLUG: Slug string for identifying the driver in format /[a-z-]+/ (required)
        NAME: User friendly name for displaying (required)
        DESCRIPTION: Description of what this driver does (required)

        MACHINE_SETTINGS: Driver specific settings dict
    """

    SLUG: str
    NAME: str
    DESCRIPTION: str

    MACHINE_SETTINGS: dict[str, SettingsKeyType]

    machine_type: str

    required_attributes = ['SLUG', 'NAME', 'DESCRIPTION', 'machine_type']

    def __init__(self) -> None:
        """Base driver __init__ method."""
        super().__init__()

        self.errors: list[Union[str, Exception]] = []

    def init_driver(self):
        """This method gets called after all machines are created and can be used to initialize the driver.

        After the driver is initialized, the self.init_machine function is
        called for each machine associated with that driver.
        """

    def init_machine(self, machine: 'BaseMachineType'):
        """This method gets called for each active machine using that driver while initialization.

        If this function raises an Exception, it gets added to the machine.errors
        list and the machine does not initialize successfully.

        Arguments:
            machine: Machine instance
        """

    def update_machine(
        self, old_machine_state: dict[str, Any], machine: 'BaseMachineType'
    ):
        """This method gets called for each update of a machine.

        Note:
            machine.restart_required can be set to True here if the machine needs a manual restart to apply the changes

        Arguments:
            old_machine_state: Dict holding the old machine state before update
            machine: Machine instance with the new state
        """

    def restart_machine(self, machine: 'BaseMachineType'):
        """This method gets called on manual machine restart e.g. by using the restart machine action in the Admin Center.

        Note:
            `machine.restart_required` gets set to False again before this function is called

        Arguments:
            machine: Machine instance
        """

    def get_machines(self, **kwargs):
        """Return all machines using this driver (By default only initialized machines).

        Keyword Arguments:
            name (str): Machine name
            machine_type (BaseMachineType): Machine type definition (class)
            initialized (bool | None): use None to get all machines (default: True)
            active (bool): machine needs to be active
            base_driver (BaseDriver): base driver (class)
        """
        from machine import registry

        kwargs.pop('driver', None)

        return registry.get_machines(driver=self, **kwargs)

    def handle_error(self, error: Union[Exception, str]):
        """Handle driver error.

        Arguments:
            error: Exception or string
        """
        self.errors.append(error)

init_driver()

This method gets called after all machines are created and can be used to initialize the driver.

After the driver is initialized, the self.init_machine function is called for each machine associated with that driver.

Source code in InvenTree/machine/machine_type.py

def init_driver(self):
    """This method gets called after all machines are created and can be used to initialize the driver.

    After the driver is initialized, the self.init_machine function is
    called for each machine associated with that driver.
    """

init_machine(machine)

This method gets called for each active machine using that driver while initialization.

If this function raises an Exception, it gets added to the machine.errors list and the machine does not initialize successfully.

Parameters:

Name	Type	Description	Default
machine	BaseMachineType	Machine instance	required

Source code in InvenTree/machine/machine_type.py

def init_machine(self, machine: 'BaseMachineType'):
    """This method gets called for each active machine using that driver while initialization.

    If this function raises an Exception, it gets added to the machine.errors
    list and the machine does not initialize successfully.

    Arguments:
        machine: Machine instance
    """

update_machine(old_machine_state, machine)

This method gets called for each update of a machine.

Note

machine.restart_required can be set to True here if the machine needs a manual restart to apply the changes

Parameters:

Name	Type	Description	Default
old_machine_state	dict[str, Any]	Dict holding the old machine state before update	required
machine	BaseMachineType	Machine instance with the new state	required

Source code in InvenTree/machine/machine_type.py

def update_machine(
    self, old_machine_state: dict[str, Any], machine: 'BaseMachineType'
):
    """This method gets called for each update of a machine.

    Note:
        machine.restart_required can be set to True here if the machine needs a manual restart to apply the changes

    Arguments:
        old_machine_state: Dict holding the old machine state before update
        machine: Machine instance with the new state
    """

restart_machine(machine)

This method gets called on manual machine restart e.g. by using the restart machine action in the Admin Center.

Note

machine.restart_required gets set to False again before this function is called

Parameters:

Name	Type	Description	Default
machine	BaseMachineType	Machine instance	required

Source code in InvenTree/machine/machine_type.py

def restart_machine(self, machine: 'BaseMachineType'):
    """This method gets called on manual machine restart e.g. by using the restart machine action in the Admin Center.

    Note:
        `machine.restart_required` gets set to False again before this function is called

    Arguments:
        machine: Machine instance
    """

get_machines(**kwargs)

Return all machines using this driver (By default only initialized machines).

Other Parameters:

Name	Type	Description
name	str	Machine name
machine_type	BaseMachineType	Machine type definition (class)
initialized	bool | None	use None to get all machines (default: True)
active	bool	machine needs to be active
base_driver	BaseDriver	base driver (class)

Source code in InvenTree/machine/machine_type.py

def get_machines(self, **kwargs):
    """Return all machines using this driver (By default only initialized machines).

    Keyword Arguments:
        name (str): Machine name
        machine_type (BaseMachineType): Machine type definition (class)
        initialized (bool | None): use None to get all machines (default: True)
        active (bool): machine needs to be active
        base_driver (BaseDriver): base driver (class)
    """
    from machine import registry

    kwargs.pop('driver', None)

    return registry.get_machines(driver=self, **kwargs)

handle_error(error)

Handle driver error.

Parameters:

Name	Type	Description	Default
error	Union[Exception, str]	Exception or string	required

Source code in InvenTree/machine/machine_type.py

def handle_error(self, error: Union[Exception, str]):
    """Handle driver error.

    Arguments:
        error: Exception or string
    """
    self.errors.append(error)

Settings

Each machine can have different settings configured. There are machine settings that are specific to that machine type and driver settings that are specific to the driver, but both can be specified individually for each machine. Define them by adding a MACHINE_SETTINGS dictionary attribute to either the driver or the machine type. The format follows the same pattern as the SETTINGS for normal plugins documented on the SettingsMixin

class MyXYZDriver(ABCBaseDriver):
    MACHINE_SETTINGS = {
        'SERVER': {
            'name': _('Server'),
            'description': _('IP/Hostname to connect to the cups server'),
            'default': 'localhost',
            'required': True,
        }
    }

Settings can even marked as 'required': True which prevents the machine from starting if the setting is not defined.

Machine status

Machine status can be used to report the machine status to the users. They can be set by the driver for each machine, but get lost on a server restart.

Codes

Each machine type has a set of status codes defined that can be set for each machine by the driver. There also needs to be a default status code defined.

from plugin.machine import MachineStatus, BaseMachineType

class XYZStatus(MachineStatus):
    CONNECTED = 100, _('Connected'), 'success'
    STANDBY = 101, _('Standby'), 'success'
    DISCONNECTED = 400, _('Disconnected'), 'danger'

class XYZMachineType(BaseMachineType):
    # ...

    MACHINE_STATUS = XYZStatus
    default_machine_status = XYZStatus.DISCONNECTED

And to set a status code for a machine by the driver.

class MyXYZDriver(ABCBaseDriver):
    # ...
    def init_machine(self, machine):
        # ... do some init stuff here
        machine.set_status(XYZMachineType.MACHINE_STATUS.CONNECTED)

MachineStatus API

Base class for representing a set of machine status codes.

Use enum syntax to define the status codes, e.g.

CONNECTED = 200, _("Connected"), 'success'

The values of the status can be accessed with MachineStatus.CONNECTED.value.

Additionally there are helpers to access all additional attributes text, label, color.

Available colors

primary, secondary, warning, danger, success, warning, info

Status code ranges

1XX - Everything fine
2XX - Warnings (e.g. ink is about to become empty)
3XX - Something wrong with the machine (e.g. no labels are remaining on the spool)
4XX - Something wrong with the driver (e.g. cannot connect to the machine)
5XX - Unknown issues

Source code in InvenTree/machine/machine_type.py

class MachineStatus(StatusCode):
    """Base class for representing a set of machine status codes.

    Use enum syntax to define the status codes, e.g.
    ```python
    CONNECTED = 200, _("Connected"), 'success'
    ```

    The values of the status can be accessed with `MachineStatus.CONNECTED.value`.

    Additionally there are helpers to access all additional attributes `text`, `label`, `color`.

    Available colors:
        primary, secondary, warning, danger, success, warning, info

    Status code ranges:
        ```
        1XX - Everything fine
        2XX - Warnings (e.g. ink is about to become empty)
        3XX - Something wrong with the machine (e.g. no labels are remaining on the spool)
        4XX - Something wrong with the driver (e.g. cannot connect to the machine)
        5XX - Unknown issues
        ```
    """

Free text

There can also be a free text status code defined.

class MyXYZDriver(ABCBaseDriver):
    # ...
    def init_machine(self, machine):
        # ... do some init stuff here
        machine.set_status_text("Paper missing")