Module aws_lambda_powertools.utilities.validation

Simple validator to enforce incoming/outgoing event conforms with JSON Schema

Sub-modules

aws_lambda_powertools.utilities.validation.base

aws_lambda_powertools.utilities.validation.envelopes

Built-in envelopes

aws_lambda_powertools.utilities.validation.exceptions

Functions

def validate(event: Any, schema: dict, formats: dict | None = None, handlers: dict | None = None, provider_options: dict | None = None, envelope: str | None = None, jmespath_options: dict | None = None) ‑> Any

Standalone function to validate event data using a JSON Schema

Typically used when you need more control over the validation process.

Parameters

event : dict

Lambda event to be validated

schema : dict

JSON Schema to validate incoming event

envelope : dict

JMESPath expression to filter data against

jmespath_options : dict

Alternative JMESPath options to be included when filtering expr

formats : dict

Custom formats containing a key (e.g. int64) and a value expressed as regex or callback returning bool

handlers : Dict

Custom methods to retrieve remote schemes, keyed off of URI scheme

provider_options : Dict

Arguments that will be passed directly to the underlying validate call

Example

Validate event

from aws_lambda_powertools.utilities.validation import validate

def handler(event, context):
    validate(event=event, schema=json_schema_dict)
    return event

Unwrap event before validating against actual payload - using built-in envelopes

from aws_lambda_powertools.utilities.validation import validate, envelopes

def handler(event, context):
    validate(event=event, schema=json_schema_dict, envelope=envelopes.API_GATEWAY_REST)
    return event

Unwrap event before validating against actual payload - using custom JMESPath expression

from aws_lambda_powertools.utilities.validation import validate

def handler(event, context):
    validate(event=event, schema=json_schema_dict, envelope="payload[*].my_data")
    return event

Unwrap and deserialize JSON string event before validating against actual payload - using built-in functions

from aws_lambda_powertools.utilities.validation import validate

def handler(event, context):
    validate(event=event, schema=json_schema_dict, envelope="Records[*].powertools_json(body)")
    return event

Unwrap, decode base64 and deserialize JSON string event before validating against actual payload - using built-in functions

from aws_lambda_powertools.utilities.validation import validate

def handler(event, context):
    validate(event=event, schema=json_schema_dict, envelope="Records[*].kinesis.powertools_json(powertools_base64(data))")
    return event

Unwrap, decompress ZIP archive and deserialize JSON string event before validating against actual payload - using built-in functions

from aws_lambda_powertools.utilities.validation import validate

def handler(event, context):
    validate(event=event, schema=json_schema_dict, envelope="awslogs.powertools_base64_gzip(data) | powertools_json(@).logEvents[*]")
    return event

Returns

Dict

The validated event. If the schema specifies a default value for fields that are omitted, those default values will be included in the response.

Raises

SchemaValidationError

When schema validation fails against data set

InvalidSchemaFormatError

When JSON schema provided is invalid

InvalidEnvelopeExpressionError

When JMESPath expression to unwrap event is invalid

def validator(handler: Callable, event: dict | str, context: Any, inbound_schema: dict | None = None, inbound_formats: dict | None = None, inbound_handlers: dict | None = None, inbound_provider_options: dict | None = None, outbound_schema: dict | None = None, outbound_formats: dict | None = None, outbound_handlers: dict | None = None, outbound_provider_options: dict | None = None, envelope: str = '', jmespath_options: dict | None = None, **kwargs: Any) ‑> Any

Lambda handler decorator to validate incoming/outbound data using a JSON Schema

Parameters

handler : Callable

Method to annotate on

event : dict

Lambda event to be validated

context : Any

Lambda context object

inbound_schema : dict

JSON Schema to validate incoming event

outbound_schema : dict

JSON Schema to validate outbound event

envelope : dict

JMESPath expression to filter data against

jmespath_options : dict

Alternative JMESPath options to be included when filtering expr

inbound_formats : dict

Custom formats containing a key (e.g. int64) and a value expressed as regex or callback returning bool

outbound_formats : dict

Custom formats containing a key (e.g. int64) and a value expressed as regex or callback returning bool

inbound_handlers : Dict

Custom methods to retrieve remote schemes, keyed off of URI scheme

outbound_handlers : Dict

Custom methods to retrieve remote schemes, keyed off of URI scheme

inbound_provider_options : Dict

Arguments that will be passed directly to the underlying validation call, in this case fastjsonchema.validate. For all supported arguments see: https://horejsek.github.io/python-fastjsonschema/#fastjsonschema.validate

outbound_provider_options : Dict

Arguments that will be passed directly to the underlying validation call, in this case fastjsonchema.validate. For all supported arguments see: https://horejsek.github.io/python-fastjsonschema/#fastjsonschema.validate

Example

Validate incoming event

from aws_lambda_powertools.utilities.validation import validator

@validator(inbound_schema=json_schema_dict)
def handler(event, context):
    return event

Validate incoming and outgoing event

from aws_lambda_powertools.utilities.validation import validator

@validator(inbound_schema=json_schema_dict, outbound_schema=response_json_schema_dict)
def handler(event, context):
    return event

Unwrap event before validating against actual payload - using built-in envelopes

from aws_lambda_powertools.utilities.validation import validator, envelopes

@validator(inbound_schema=json_schema_dict, envelope=envelopes.API_GATEWAY_REST)
def handler(event, context):
    return event

Unwrap event before validating against actual payload - using custom JMESPath expression

from aws_lambda_powertools.utilities.validation import validator

@validator(inbound_schema=json_schema_dict, envelope="payload[*].my_data")
def handler(event, context):
    return event

Unwrap and deserialize JSON string event before validating against actual payload - using built-in functions

from aws_lambda_powertools.utilities.validation import validator

@validator(inbound_schema=json_schema_dict, envelope="Records[*].powertools_json(body)")
def handler(event, context):
    return event

Unwrap, decode base64 and deserialize JSON string event before validating against actual payload - using built-in functions

from aws_lambda_powertools.utilities.validation import validator

@validator(inbound_schema=json_schema_dict, envelope="Records[*].kinesis.powertools_json(powertools_base64(data))")
def handler(event, context):
    return event

Unwrap, decompress ZIP archive and deserialize JSON string event before validating against actual payload - using built-in functions

from aws_lambda_powertools.utilities.validation import validator

@validator(inbound_schema=json_schema_dict, envelope="awslogs.powertools_base64_gzip(data) | powertools_json(@).logEvents[*]")
def handler(event, context):
    return event

Returns

Any

Lambda handler response

Raises

SchemaValidationError

When schema validation fails against data set

InvalidSchemaFormatError

When JSON schema provided is invalid

InvalidEnvelopeExpressionError

When JMESPath expression to unwrap event is invalid

Classes

class InvalidEnvelopeExpressionError (*args, **kwargs)

When JMESPath fails to parse expression

Expand source code

class InvalidEnvelopeExpressionError(Exception):
    """When JMESPath fails to parse expression"""

Ancestors

• builtins.Exception
• builtins.BaseException

class InvalidSchemaFormatError (*args, **kwargs)

When JSON Schema is in invalid format

Expand source code

class InvalidSchemaFormatError(Exception):
    """When JSON Schema is in invalid format"""

Ancestors

• builtins.Exception
• builtins.BaseException

class SchemaValidationError (message: str | None = None, validation_message: str | None = None, name: str | None = None, path: list | None = None, value: Any | None = None, definition: Any | None = None, rule: str | None = None, rule_definition: Any | None = None)

When serialization fail schema validation

Parameters

message : str, optional

Powertools for AWS Lambda (Python) formatted error message

validation_message : str, optional

Containing human-readable information what is wrong (e.g. data.property[index] must be smaller than or equal to 42)

name : str, optional

name of a path in the data structure (e.g. data.property[index])

path : list, optional

path as an array in the data structure (e.g. ['data', 'property', 'index']),

value : Any, optional

The invalid value

definition : Any, optional

The full rule definition (e.g. 42)

rule : str, optional

rule which the data is breaking (e.g. maximum)

rule_definition : Any, optional

The specific rule definition (e.g. 42)

Expand source code

class SchemaValidationError(Exception):
    """When serialization fail schema validation"""

    def __init__(
        self,
        message: str | None = None,
        validation_message: str | None = None,
        name: str | None = None,
        path: list | None = None,
        value: Any | None = None,
        definition: Any | None = None,
        rule: str | None = None,
        rule_definition: Any | None = None,
    ):
        """

        Parameters
        ----------
        message : str, optional
            Powertools for AWS Lambda (Python) formatted error message
        validation_message : str, optional
            Containing human-readable information what is wrong
            (e.g. `data.property[index] must be smaller than or equal to 42`)
        name : str, optional
            name of a path in the data structure
            (e.g. `data.property[index]`)
        path: list, optional
            `path` as an array in the data structure
            (e.g. `['data', 'property', 'index']`),
        value : Any, optional
            The invalid value
        definition : Any, optional
            The full rule `definition`
            (e.g. `42`)
        rule : str, optional
            `rule` which the `data` is breaking
            (e.g. `maximum`)
        rule_definition : Any, optional
            The specific rule `definition`
            (e.g. `42`)
        """
        super().__init__(message)
        self.message = message
        self.validation_message = validation_message
        self.name = name
        self.path = path
        self.value = value
        self.definition = definition
        self.rule = rule
        self.rule_definition = rule_definition

Ancestors

• builtins.Exception
• builtins.BaseException