Message object. More...

#include <rdkafkacpp.h>

Public Types
enum	Status { MSG_STATUS_NOT_PERSISTED = 0 , MSG_STATUS_POSSIBLY_PERSISTED = 1 , MSG_STATUS_PERSISTED = 2 }
	Message persistence status can be used by the application to find out if a produced message was persisted in the topic log. More...

Public Member Functions
virtual std::string	errstr () const =0
	Accessor functions*. More...

virtual ErrorCode	err () const =0

virtual Topic *	topic () const =0

virtual std::string	topic_name () const =0

virtual int32_t	partition () const =0

virtual void *	payload () const =0

virtual size_t	len () const =0

virtual const std::string *	key () const =0

virtual const void *	key_pointer () const =0

virtual size_t	key_len () const =0

virtual int64_t	offset () const =0

virtual MessageTimestamp	timestamp () const =0

virtual void *	msg_opaque () const =0

virtual int64_t	latency () const =0

virtual struct rd_kafka_message_s *	c_ptr ()=0
	Returns the underlying librdkafka C rd_kafka_message_t handle. More...

virtual Status	status () const =0
	Returns the message's persistence status in the topic log.

virtual RdKafka::Headers *	headers ()=0

virtual RdKafka::Headers *	headers (RdKafka::ErrorCode *err)=0

virtual int32_t	broker_id () const =0

virtual int32_t	leader_epoch () const =0

virtual Error *	offset_store ()=0
	Store offset +1 for the consumed message. More...

Detailed Description

Message object.

This object represents either a single consumed or produced message, or an event (err() is set).

An application must check RdKafka::Message::err() to see if the object is a proper message (error is RdKafka::ERR_NO_ERROR) or a an error event.

Member Enumeration Documentation

◆ Status

enum RdKafka::Message::Status

Message persistence status can be used by the application to find out if a produced message was persisted in the topic log.

Enumerator
MSG_STATUS_NOT_PERSISTED	Message was never transmitted to the broker, or failed with an error indicating it was not written to the log. Application retry risks ordering, but not duplication.
MSG_STATUS_POSSIBLY_PERSISTED	Message was transmitted to broker, but no acknowledgement was received. Application retry risks ordering and duplication.
MSG_STATUS_PERSISTED	Message was written to the log and fully acknowledged. No reason for application to retry. Note: this value should only be trusted with `acks=all`.

Member Function Documentation

◆ errstr()

virtual std::string RdKafka::Message::errstr ( ) const

pure virtual

Accessor functions*.

Remarks: Not all fields are present in all types of callbacks.

Returns: The error string if object represent an error event, else an empty string.

◆ err()

virtual ErrorCode RdKafka::Message::err ( ) const

pure virtual

Returns: The error code if object represents an error event, else 0.

◆ topic()

virtual Topic* RdKafka::Message::topic ( ) const

pure virtual

Returns: the RdKafka::Topic object for a message (if applicable), or NULL if a corresponding RdKafka::Topic object has not been explicitly created with RdKafka::Topic::create(). In this case use topic_name() instead.

◆ topic_name()

virtual std::string RdKafka::Message::topic_name ( ) const

pure virtual

Returns: Topic name (if applicable, else empty string)

◆ partition()

virtual int32_t RdKafka::Message::partition ( ) const

pure virtual

Returns: Partition (if applicable)

◆ payload()

virtual void* RdKafka::Message::payload ( ) const

pure virtual

Returns: Message payload (if applicable)

◆ len()

virtual size_t RdKafka::Message::len ( ) const

pure virtual

Returns: Message payload length (if applicable)

◆ key()

virtual const std::string* RdKafka::Message::key ( ) const

pure virtual

Returns: Message key as string (if applicable)

◆ key_pointer()

virtual const void* RdKafka::Message::key_pointer ( ) const

pure virtual

Returns: Message key as void pointer (if applicable)

◆ key_len()

virtual size_t RdKafka::Message::key_len ( ) const

pure virtual

Returns: Message key's binary length (if applicable)

◆ offset()

virtual int64_t RdKafka::Message::offset ( ) const

pure virtual

Returns: Message or error offset (if applicable)

◆ timestamp()

virtual MessageTimestamp RdKafka::Message::timestamp ( ) const

pure virtual

Returns: Message timestamp (if applicable)

◆ msg_opaque()

virtual void* RdKafka::Message::msg_opaque ( ) const

pure virtual

Returns: The msg_opaque as provided to RdKafka::Producer::produce()

◆ latency()

virtual int64_t RdKafka::Message::latency ( ) const

pure virtual

Returns: the latency in microseconds for a produced message measured from the produce() call, or -1 if latency is not available.

◆ c_ptr()

virtual struct rd_kafka_message_s* RdKafka::Message::c_ptr ( )

pure virtual

Returns the underlying librdkafka C rd_kafka_message_t handle.

Warning: Calling the C API on this handle is not recommended and there is no official support for it, but for cases where the C++ API does not provide the underlying functionality this C handle can be used to interact directly with the core librdkafka API.

Remarks: The lifetime of the returned pointer is the same as the Message object this method is called on.; Include <rdkafka/rdkafka.h> prior to including <rdkafka/rdkafkacpp.h>

Returns: rd_kafka_message_t*

◆ headers() [1/2]

virtual RdKafka::Headers* RdKafka::Message::headers ( )

pure virtual

Returns: the Headers instance for this Message, or NULL if there are no headers.

Remarks: The lifetime of the Headers are the same as the Message.

◆ headers() [2/2]

virtual RdKafka::Headers* RdKafka::Message::headers ( RdKafka::ErrorCode * err )

pure virtual

Returns: the Headers instance for this Message (if applicable). If NULL is returned the reason is given in err, which is either ERR__NOENT if there were no headers, or another error code if header parsing failed.

Remarks: The lifetime of the Headers are the same as the Message.

◆ broker_id()

virtual int32_t RdKafka::Message::broker_id ( ) const

pure virtual

Returns: the broker id of the broker the message was produced to or fetched from, or -1 if not known/applicable.

◆ leader_epoch()

virtual int32_t RdKafka::Message::leader_epoch ( ) const

pure virtual

Returns: the message's partition leader epoch at the time the message was fetched and if known, else -1.

◆ offset_store()

virtual Error* RdKafka::Message::offset_store ( )

pure virtual

Store offset +1 for the consumed message.

The message offset + 1 will be committed to broker according to auto.commit.interval.ms or manual offset-less commit()

Warning: This method may only be called for partitions that are currently assigned. Non-assigned partitions will fail with ERR__STATE.; Avoid storing offsets after calling seek() (et.al) as this may later interfere with resuming a paused partition, instead store offsets prior to calling seek.

Remarks: enable.auto.offset.store must be set to "false" when using this API.

Returns: NULL on success or an error object on failure.

The documentation for this class was generated from the following file:

src-cpp/rdkafkacpp.h

Public Types

Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ Status

Member Function Documentation

◆ errstr()

◆ err()

◆ topic()

◆ topic_name()

◆ partition()

◆ payload()

◆ len()

◆ key()

◆ key_pointer()

◆ key_len()

◆ offset()

◆ timestamp()

◆ msg_opaque()

◆ latency()

◆ c_ptr()

◆ headers() [1/2]

◆ headers() [2/2]

◆ broker_id()

◆ leader_epoch()

◆ offset_store()