Module aws_lambda_powertools.utilities.data_classes.kafka_event

Classes

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

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
    """

    @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:
        """The next Kafka record."""
        return next(self.records)

Ancestors

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

Instance variables

var bootstrap_servers : str

The Kafka bootstrap URL.

Expand source code

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

var 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(",")

var 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"]

var 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")

var record : KafkaEventRecord

The next Kafka record.

Expand source code

@property
def record(self) -> KafkaEventRecord:
    """The next Kafka record."""
    return next(self.records)

var 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) -> str:
        """The Kafka record parition."""
        return self["partition"]

    @property
    def offset(self) -> str:
        """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)

    @property
    def json_value(self) -> Any:
        """Decodes the text encoded data as JSON."""
        if self._json_data is None:
            self._json_data = self._json_deserializer(self.decoded_value.decode("utf-8"))
        return self._json_data

    @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()}

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

        return next(
            # Iterate over the dict and do a case-insensitive key comparison
            (value for key, value in self.decoded_headers.items() if key.lower() == name_lower),
            # Default value is returned if no matches was found
            default_value,
        )

Ancestors

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

Instance variables

var 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()}

var 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)

var 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)

var 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 : Any

Decodes the text encoded data as JSON.

Expand source code

@property
def json_value(self) -> Any:
    """Decodes the text encoded data as JSON."""
    if self._json_data is None:
        self._json_data = self._json_deserializer(self.decoded_value.decode("utf-8"))
    return self._json_data

var 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"]

var offset : str

The Kafka record offset.

Expand source code

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

var partition : str

The Kafka record parition.

Expand source code

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

var timestamp : int

The Kafka record timestamp.

Expand source code

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

var 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"]

var topic : str

The Kafka topic.

Expand source code

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

var 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[Any] = None, case_sensitive: bool = True) ‑> Optional[bytes]

Get a decoded header value by name.

Expand source code

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

    return next(
        # Iterate over the dict and do a case-insensitive key comparison
        (value for key, value in self.decoded_headers.items() if key.lower() == name_lower),
        # Default value is returned if no matches was found
        default_value,
    )

Inherited members

• DictWrapper:
  • get
  • raw_event