Module aws_lambda_powertools.utilities.data_classes.kafka_event

Classes

class KafkaEvent (data: Dict[str, Any])

Self-managed or MSK Apache Kafka event trigger Documentation:

---

• https://docs.aws.amazon.com/lambda/latest/dg/with-kafka.html
• https://docs.aws.amazon.com/lambda/latest/dg/with-msk.html

Parameters

data : Dict[str, Any]

Lambda Event Source Event payload

json_deserializer : Callable, optional

function to deserialize str, bytes, bytearray containing a JSON document to a Python obj, by default json.loads

Expand source code

class KafkaEvent(DictWrapper):
    """Self-managed or MSK Apache Kafka event trigger
    Documentation:
    --------------
    - https://docs.aws.amazon.com/lambda/latest/dg/with-kafka.html
    - https://docs.aws.amazon.com/lambda/latest/dg/with-msk.html
    """

    def __init__(self, data: Dict[str, Any]):
        super().__init__(data)
        self._records: Optional[Iterator[KafkaEventRecord]] = None

    @property
    def event_source(self) -> str:
        """The AWS service from which the Kafka event record originated."""
        return self["eventSource"]

    @property
    def event_source_arn(self) -> Optional[str]:
        """The AWS service ARN from which the Kafka event record originated, mandatory for AWS MSK."""
        return self.get("eventSourceArn")

    @property
    def bootstrap_servers(self) -> str:
        """The Kafka bootstrap URL."""
        return self["bootstrapServers"]

    @property
    def decoded_bootstrap_servers(self) -> List[str]:
        """The decoded Kafka bootstrap URL."""
        return self.bootstrap_servers.split(",")

    @property
    def records(self) -> Iterator[KafkaEventRecord]:
        """The Kafka records."""
        for chunk in self["records"].values():
            for record in chunk:
                yield KafkaEventRecord(data=record, json_deserializer=self._json_deserializer)

    @property
    def record(self) -> KafkaEventRecord:
        """
        Returns the next Kafka record using an iterator.

        Returns
        -------
        KafkaEventRecord
            The next Kafka record.

        Raises
        ------
        StopIteration
            If there are no more records available.

        """
        if self._records is None:
            self._records = self.records
        return next(self._records)

Ancestors

• DictWrapper
• collections.abc.Mapping
• collections.abc.Collection
• collections.abc.Sized
• collections.abc.Iterable
• collections.abc.Container

Instance variables

prop bootstrap_servers : str

The Kafka bootstrap URL.

Expand source code

@property
def bootstrap_servers(self) -> str:
    """The Kafka bootstrap URL."""
    return self["bootstrapServers"]

prop decoded_bootstrap_servers : List[str]

The decoded Kafka bootstrap URL.

Expand source code

@property
def decoded_bootstrap_servers(self) -> List[str]:
    """The decoded Kafka bootstrap URL."""
    return self.bootstrap_servers.split(",")

prop event_source : str

The AWS service from which the Kafka event record originated.

Expand source code

@property
def event_source(self) -> str:
    """The AWS service from which the Kafka event record originated."""
    return self["eventSource"]

prop event_source_arn : Optional[str]

The AWS service ARN from which the Kafka event record originated, mandatory for AWS MSK.

Expand source code

@property
def event_source_arn(self) -> Optional[str]:
    """The AWS service ARN from which the Kafka event record originated, mandatory for AWS MSK."""
    return self.get("eventSourceArn")

prop record : KafkaEventRecord

Returns the next Kafka record using an iterator.

Returns

KafkaEventRecord

The next Kafka record.

Raises

StopIteration

If there are no more records available.

Expand source code

@property
def record(self) -> KafkaEventRecord:
    """
    Returns the next Kafka record using an iterator.

    Returns
    -------
    KafkaEventRecord
        The next Kafka record.

    Raises
    ------
    StopIteration
        If there are no more records available.

    """
    if self._records is None:
        self._records = self.records
    return next(self._records)

prop records : Iterator[KafkaEventRecord]

The Kafka records.

Expand source code

@property
def records(self) -> Iterator[KafkaEventRecord]:
    """The Kafka records."""
    for chunk in self["records"].values():
        for record in chunk:
            yield KafkaEventRecord(data=record, json_deserializer=self._json_deserializer)

Inherited members

• DictWrapper:
  • get
  • raw_event

class KafkaEventRecord (data: Dict[str, Any], json_deserializer: Optional[Callable] = None)

Provides a single read only access to a wrapper dict

Parameters

data : Dict[str, Any]

Lambda Event Source Event payload

json_deserializer : Callable, optional

function to deserialize str, bytes, bytearray containing a JSON document to a Python obj, by default json.loads

Expand source code

class KafkaEventRecord(DictWrapper):
    @property
    def topic(self) -> str:
        """The Kafka topic."""
        return self["topic"]

    @property
    def partition(self) -> int:
        """The Kafka record parition."""
        return self["partition"]

    @property
    def offset(self) -> int:
        """The Kafka record offset."""
        return self["offset"]

    @property
    def timestamp(self) -> int:
        """The Kafka record timestamp."""
        return self["timestamp"]

    @property
    def timestamp_type(self) -> str:
        """The Kafka record timestamp type."""
        return self["timestampType"]

    @property
    def key(self) -> str:
        """The raw (base64 encoded) Kafka record key."""
        return self["key"]

    @property
    def decoded_key(self) -> bytes:
        """Decode the base64 encoded key as bytes."""
        return base64.b64decode(self.key)

    @property
    def value(self) -> str:
        """The raw (base64 encoded) Kafka record value."""
        return self["value"]

    @property
    def decoded_value(self) -> bytes:
        """Decodes the base64 encoded value as bytes."""
        return base64.b64decode(self.value)

    @cached_property
    def json_value(self) -> Any:
        """Decodes the text encoded data as JSON."""
        return self._json_deserializer(self.decoded_value.decode("utf-8"))

    @property
    def headers(self) -> List[Dict[str, List[int]]]:
        """The raw Kafka record headers."""
        return self["headers"]

    @property
    def decoded_headers(self) -> Dict[str, bytes]:
        """Decodes the headers as a single dictionary."""
        return {k: bytes(v) for chunk in self.headers for k, v in chunk.items()}

    @overload
    def get_header_value(
        self,
        name: str,
        default_value: str,
        case_sensitive: bool = True,
    ) -> str: ...

    @overload
    def get_header_value(
        self,
        name: str,
        default_value: Optional[str] = None,
        case_sensitive: bool = True,
    ) -> Optional[str]: ...

    def get_header_value(
        self,
        name: str,
        default_value: Optional[str] = None,
        case_sensitive: bool = True,
    ) -> Optional[str]:
        """Get a decoded header value by name."""
        return get_header_value(
            headers=self.decoded_headers,
            name=name,
            default_value=default_value,
            case_sensitive=case_sensitive,
        )

Ancestors

• DictWrapper
• collections.abc.Mapping
• collections.abc.Collection
• collections.abc.Sized
• collections.abc.Iterable
• collections.abc.Container

Instance variables

prop decoded_headers : Dict[str, bytes]

Decodes the headers as a single dictionary.

Expand source code

@property
def decoded_headers(self) -> Dict[str, bytes]:
    """Decodes the headers as a single dictionary."""
    return {k: bytes(v) for chunk in self.headers for k, v in chunk.items()}

prop decoded_key : bytes

Decode the base64 encoded key as bytes.

Expand source code

@property
def decoded_key(self) -> bytes:
    """Decode the base64 encoded key as bytes."""
    return base64.b64decode(self.key)

prop decoded_value : bytes

Decodes the base64 encoded value as bytes.

Expand source code

@property
def decoded_value(self) -> bytes:
    """Decodes the base64 encoded value as bytes."""
    return base64.b64decode(self.value)

prop headers : List[Dict[str, List[int]]]

The raw Kafka record headers.

Expand source code

@property
def headers(self) -> List[Dict[str, List[int]]]:
    """The raw Kafka record headers."""
    return self["headers"]

var json_value

Decodes the text encoded data as JSON.

Expand source code

def __get__(self, instance, owner=None):
    if instance is None:
        return self
    if self.attrname is None:
        raise TypeError(
            "Cannot use cached_property instance without calling __set_name__ on it.")
    try:
        cache = instance.__dict__
    except AttributeError:  # not all objects have __dict__ (e.g. class defines slots)
        msg = (
            f"No '__dict__' attribute on {type(instance).__name__!r} "
            f"instance to cache {self.attrname!r} property."
        )
        raise TypeError(msg) from None
    val = cache.get(self.attrname, _NOT_FOUND)
    if val is _NOT_FOUND:
        val = self.func(instance)
        try:
            cache[self.attrname] = val
        except TypeError:
            msg = (
                f"The '__dict__' attribute on {type(instance).__name__!r} instance "
                f"does not support item assignment for caching {self.attrname!r} property."
            )
            raise TypeError(msg) from None
    return val

prop key : str

The raw (base64 encoded) Kafka record key.

Expand source code

@property
def key(self) -> str:
    """The raw (base64 encoded) Kafka record key."""
    return self["key"]

prop offset : int

The Kafka record offset.

Expand source code

@property
def offset(self) -> int:
    """The Kafka record offset."""
    return self["offset"]

prop partition : int

The Kafka record parition.

Expand source code

@property
def partition(self) -> int:
    """The Kafka record parition."""
    return self["partition"]

prop timestamp : int

The Kafka record timestamp.

Expand source code

@property
def timestamp(self) -> int:
    """The Kafka record timestamp."""
    return self["timestamp"]

prop timestamp_type : str

The Kafka record timestamp type.

Expand source code

@property
def timestamp_type(self) -> str:
    """The Kafka record timestamp type."""
    return self["timestampType"]

prop topic : str

The Kafka topic.

Expand source code

@property
def topic(self) -> str:
    """The Kafka topic."""
    return self["topic"]

prop value : str

The raw (base64 encoded) Kafka record value.

Expand source code

@property
def value(self) -> str:
    """The raw (base64 encoded) Kafka record value."""
    return self["value"]

Methods

def get_header_value(self, name: str, default_value: Optional[str] = None, case_sensitive: bool = True) ‑> Optional[str]

Get a decoded header value by name.

Inherited members

• DictWrapper:
  • get
  • raw_event