Custom Error Messages¶

You can add custom error message to validators via the err_msg parameter. If you would like to interpolate the argument names and values into your message, you can do that using the following syntax:

• ${arg_name}: To interpolate the name of the argument
• ${arg_value}: To interpolate the value of the argument

If you are using the DependsOn validator, you can further customize your error message using two extra interpolated values as follows:

• ${dep_arg_name}: To interpolate the name of the dependent argument
• ${dep_arg_value}: To interpolate the value of the dependent argument

You can also provide extra interpolated arguments via the extra_msg_args parameter using a Python dictionary where the keys are the names used in the err_msg (${key}) and values are the interpolated values.

Example Custom Message¶

In [11]:

# Config to have a single line output of Exception error message
import sys; sys.tracebacklimit = 0;
%xmode plain

# Config to have a single line output of Exception error message import sys; sys.tracebacklimit = 0; %xmode plain

Exception reporting mode: Plain

Imports¶

In [12]:

from typing import Annotated

from func_validator import validate_params, DependsOn, MustBePositive, MustBeLessThan

from typing import Annotated from func_validator import validate_params, DependsOn, MustBePositive, MustBeLessThan

Custom Message Without Interpolation¶

In [13]:

@validate_params
def example_func(
        arg_1: Annotated[float, MustBePositive(err_msg="Must be greater than zero")]
): ...

@validate_params def example_func( arg_1: Annotated[float, MustBePositive(err_msg="Must be greater than zero")] ): ...

In [14]:

example_func(-10)

example_func(-10)

ValidationError: Must be greater than zero

Custom Message With Interpolation¶

In [15]:

@validate_params
def example_func_2(
        arg_2: Annotated[float, MustBePositive(err_msg="${arg_name} should be greater than zero not ${arg_value}")]
):...

@validate_params def example_func_2( arg_2: Annotated[float, MustBePositive(err_msg="${arg_name} should be greater than zero not ${arg_value}")] ):...

In [16]:

example_func_2(-10)

example_func_2(-10)

ValidationError: arg_2 should be greater than zero not -10

In [17]:

@validate_params
def example_func_3(
        age: int,
        height: Annotated[int,
                          DependsOn("age", args_strategy=MustBeLessThan, err_msg="${arg_name}: ${arg_value} should be less than ${dep_arg_name}: ${dep_arg_value}")
        ],
): ...

@validate_params def example_func_3( age: int, height: Annotated[int, DependsOn("age", args_strategy=MustBeLessThan, err_msg="${arg_name}: ${arg_value} should be less than ${dep_arg_name}: ${dep_arg_value}") ], ): ...

In [18]:

example_func_3(10, 14)

example_func_3(10, 14)

ValidationError: height: 14 must be < 10.

Custom Message With Extra Interpolated Arguments¶

In [22]:

@validate_params
def example_func_4(age: Annotated[int,
                                MustBePositive(
                                    err_msg="${name} ${arg_name} should be greater than zero not ${arg_value}",
                                    extra_msg_args={"name": "Patrick's"}
                                   )
                                 ]
                   ): ...

@validate_params def example_func_4(age: Annotated[int, MustBePositive( err_msg="${name} ${arg_name} should be greater than zero not ${arg_value}", extra_msg_args={"name": "Patrick's"} ) ] ): ...

In [23]:

example_func_4(-10)

example_func_4(-10)

ValidationError: Patrick's age should be greater than zero not -10