Developing Validators

Validators are sanity checks that gets run during publishing. They are defined in the validate directory -> tik_manager4/dcc/<dcc_name>/validate.

Tip

Starting from v4.3.8, Tik Manager can access validators from <common>/plugins/maya/validation/ folder. This is the suggested location for any custom validators as they will be immediately available with the entire team and won’t be affected by Tik Manager version updates.

Below is a simple example of a validator for Maya that checks if the work file is following a hierarchy convention.

"""Example Hierarchy Checker for Maya."""

from maya import cmds
from tik_manager4.dcc.validate_core import ValidateCore

class HierarchyChecker(ValidateCore):
    """Simple Hierarchy Checker for Maya."""

    nice_name = "Hierarchy Checker"

    def __init__(self):
        super().__init__()
        self.autofixable = True
        self.ignorable = False
        self.selectable = True

    def collect(self):
        """Collect the transform nodes in the root."""
        default_cams = ["front", "persp", "side", "top"]
        self.collection = [node for node in cmds.ls(assemblies=True) if node not in default_cams]

    def validate(self):
        """Check if the hierarchy is correct."""
        self.collect()

        # let's say our pipe requires each publish needs to be stored under a single group.
        if len(self.collection) > 1:
            self.failed(msg="More than one root node found.")
            return

        # the root group needs to be named as root
        if self.collection[0] != "root":
            self.failed(msg="Root node is not named as 'root'.")
            return

        # the root group must have exactly 3 child groups called render, guide and proxy
        children = cmds.listRelatives(self.collection[0], children=True)
        if not children:
            self.failed(msg="No child groups found.")
            return

        if len(children) != 3:
            self.failed(msg="Exactly 3 child groups are required.")
            return

        if not all([child in ["render", "guide", "proxy"] for child in children]):
            self.failed(msg="Child groups are not named correctly.")
            return

        self.passed()

    def fix(self):
        """Fix the hierarchy."""
        self.collect()
        if len(self.collection) > 1:
            # there are more groups than expected, We tag this unfixable
            added_message = f"{self.fail_message}\nAuto-fix failed."
            self.failed(msg=added_message)
            return
        if self.collection[0] != "root":
            cmds.rename(self.collection[0], "root")

    def select(self):
        """Select any root nodes other than the 'root'."""
        self.collect()
        cmds.select([node for node in self.collection if node != "root"])
Detailed Explanation

First we import the necessary modules and classes.

from maya import cmds
from tik_manager4.dcc.validate_core import ValidateCore

Then we define our validator class.

class HierarchyChecker(ValidateCore):
    """Simple Hierarchy Checker for Maya."""

    nice_name = "Hierarchy Checker"

It is important to inherit from the ValidateCore class. This class provides the necessary methods and properties to create a validator. Than we define the nice_name attribute. This is the name of the validator that will be displayed to the user.

def __init__(self):
    super().__init__()
    self.autofixable = True
    self.ignorable = False
    self.selectable = True

In the __init__ method, we define the autofixable, ignorable and selectable attributes. These attributes are used to determine the behavior of the validator. If autofixable is set to True, the user will be able to automatically fix the issue. If ignorable is set to True, the user will be able to ignore the issue. If selectable is set to True, the user will be able to select the problematic nodes.

Next we define the collect method. This method is used to collect the items that will be validated. In this case, we are collecting the transform nodes in the root.

def collect(self):
    """Collect the transform nodes in the root."""
    default_cams = ["front", "persp", "side", "top"]
    self.collection = [node for node in cmds.ls(assemblies=True) if node not in default_cams]

Afterwards we define the validate method. This method is used to check if the collected items are following the convention.

def validate(self):
    """Check if the hierarchy is correct."""
    self.collect()

    # let's say our pipe requires each publish needs to be stored under a single group.
    if len(self.collection) > 1:
        self.failed(msg="More than one root node found.")
        return

    # the root group needs to be named as root
    if self.collection[0] != "root":
        self.failed(msg="Root node is not named as 'root'.")
        return

    # the root group must have exactly 3 child groups called render, guide and proxy
    children = cmds.listRelatives(self.collection[0], children=True)
    if not children:
        self.failed(msg="No child groups found.")
        return

    if len(children) != 3:
        self.failed(msg="Exactly 3 child groups are required.")
        return

    if not all([child in ["render", "guide", "proxy"] for child in children]):
        self.failed(msg="Child groups are not named correctly.")
        return

    self.passed()

The ‘validate’ method is actually overridden from the parent class. The parent class has a default implementation that always passes. It is important to call the passed or failed methods to set the state of the validation. If the validation fails, the failed method is called with a message. If the validation passes, the passed method is called.

Next we define the fix method. This method is used to fix the issue automatically.

def fix(self):
    """Fix the hierarchy."""
    self.collect()
    if len(self.collection) > 1:
        # there are more groups than expected, We tag this unfixable
        added_message = f"{self.fail_message}\nAuto-fix failed."
        self.failed(msg=added_message)
        return
    if self.collection[0] != "root":
        cmds.rename(self.collection[0], "root")

In this example, just for the purpose of demonstration, We first checking the length of the collection. If there are more than one root nodes, we tag this as unfixable. If the issue cannot be fixed, the failed method is called with a message. For the sake of simplicity and demonstration, we only check if the root node is named as root and renaming it if it is not.

Finally we define the select method. This method is used to select the problematic nodes.

def select(self):
    """Select any root nodes other than the 'root'."""
    self.collect()
    cmds.select([node for node in self.collection if node != "root"])

Again, for the sake of simplicity and demonstration, we are selecting the root nodes other than the one named as root.

Similar to validate and fix methods, the select method is also overridden from the parent class. The parent class has a default implementation that does nothing.

Note

fix and select methods are optional and they will only become active if the autofixable and selectable attributes are set to True respectively.

Common Validator Attributes

Class attributes:

  • nice_name: The name of the validator that will be displayed to the user.

  • checked_by_default: If True, the validator will be active by default.

Instance attributes:

  • ignorable: If True, the validator can be ignored by the user even if it fails.

  • autofixable: If True, it will be possible to automatically fix the issue [1].

  • selectable: If True, the user can select the culprit nodes [2].

  • collection: List of items to be validated. Can be hardcoded or defined by logic functions.

Properties:

  • state: The state of validation. Can be idle, failed, passed or ignored.

  • fail_message: The message to be displayed when the validation fails.

  • metadata: The metadata coming from the sub-project of the work file about to be published.