mirror of
https://github.com/Telecominfraproject/wlan-cloud-lib-cppkafka.git
synced 2025-10-31 18:47:48 +00:00
344 lines
11 KiB
C++
344 lines
11 KiB
C++
/*
|
|
* Copyright (c) 2017, Matias Fontanini
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions are
|
|
* met:
|
|
*
|
|
* * Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* * Redistributions in binary form must reproduce the above
|
|
* copyright notice, this list of conditions and the following disclaimer
|
|
* in the documentation and/or other materials provided with the
|
|
* distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
|
|
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
|
|
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
|
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
|
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
*/
|
|
|
|
#ifndef CPP_KAFKA_CONSUMER_H
|
|
#define CPP_KAFKA_CONSUMER_H
|
|
|
|
#include <vector>
|
|
#include <string>
|
|
#include <chrono>
|
|
#include <functional>
|
|
#include "kafka_handle_base.h"
|
|
#include "message.h"
|
|
#include "macros.h"
|
|
#include "error.h"
|
|
|
|
namespace cppkafka {
|
|
|
|
class TopicConfiguration;
|
|
|
|
/**
|
|
* \brief High level kafka consumer class
|
|
*
|
|
* Wrapper for the high level consumer API provided by rdkafka. Most methods are just
|
|
* a one to one mapping to rdkafka functions.
|
|
*
|
|
* This class allows hooking up to assignments/revocations via callbacks.
|
|
*
|
|
* Semi-simple code showing how to use this class
|
|
*
|
|
* \code
|
|
* // Create a configuration and set the group.id and broker list fields
|
|
* Configuration config = {
|
|
* { "metadata.broker.list", "127.0.0.1:9092" },
|
|
* { "group.id", "foo" }
|
|
* };
|
|
*
|
|
* // Create a consumer
|
|
* Consumer consumer(config);
|
|
*
|
|
* // Set the assignment callback
|
|
* consumer.set_assignment_callback([&](vector<TopicPartition>& topic_partitions) {
|
|
* // Here you could fetch offsets and do something, altering the offsets on the
|
|
* // topic_partitions vector if needed
|
|
* cout << "Got assigned " << topic_partitions.count() << " partitions!" << endl;
|
|
* });
|
|
*
|
|
* // Set the revocation callback
|
|
* consumer.set_revocation_callback([&](const vector<TopicPartition>& topic_partitions) {
|
|
* cout << topic_partitions.size() << " partitions revoked!" << endl;
|
|
* });
|
|
*
|
|
* // Subscribe
|
|
* consumer.subscribe({ "my_topic" });
|
|
* while (true) {
|
|
* // Poll. This will optionally return a message. It's necessary to check if it's a valid
|
|
* // one before using it
|
|
* Message msg = consumer.poll();
|
|
* if (msg) {
|
|
* if (!msg.get_error()) {
|
|
* // It's an actual message. Get the payload and print it to stdout
|
|
* cout << msg.get_payload().as_string() << endl;
|
|
* }
|
|
* else if (!msg.is_eof()) {
|
|
* // Is it an error notification, handle it.
|
|
* // This is explicitly skipping EOF notifications as they're not actually errors,
|
|
* // but that's how rdkafka provides them
|
|
* }
|
|
* }
|
|
* }
|
|
* \endcode
|
|
*/
|
|
class CPPKAFKA_API Consumer : public KafkaHandleBase {
|
|
public:
|
|
using AssignmentCallback = std::function<void(TopicPartitionList&)>;
|
|
using RevocationCallback = std::function<void(const TopicPartitionList&)>;
|
|
using RebalanceErrorCallback = std::function<void(Error)>;
|
|
|
|
/**
|
|
* \brief Creates an instance of a consumer.
|
|
*
|
|
* Note that the configuration *must contain* the group.id attribute set or this
|
|
* will throw.
|
|
*
|
|
* \param config The configuration to be used
|
|
*/
|
|
Consumer(Configuration config);
|
|
Consumer(const Consumer&) = delete;
|
|
Consumer(Consumer&) = delete;
|
|
Consumer& operator=(const Consumer&) = delete;
|
|
Consumer& operator=(Consumer&&) = delete;
|
|
|
|
/**
|
|
* \brief Closes and estroys the rdkafka handle
|
|
*
|
|
* This will call Consumer::close before destroying the handle
|
|
*/
|
|
~Consumer();
|
|
|
|
/**
|
|
* \brief Sets the topic/partition assignment callback
|
|
*
|
|
* The Consumer class will use rd_kafka_conf_set_rebalance_cb and will handle the
|
|
* rebalance, converting from rdkafka topic partition list handles into vector<TopicPartition>
|
|
* and executing the assignment/revocation/rebalance_error callbacks.
|
|
*
|
|
* \note You *do not need* to call Consumer::assign with the provided topic parttitions. This
|
|
* will be handled automatically by cppkafka.
|
|
*
|
|
* \param callback The topic/partition assignment callback
|
|
*/
|
|
void set_assignment_callback(AssignmentCallback callback);
|
|
|
|
/**
|
|
* \brief Sets the topic/partition revocation callback
|
|
*
|
|
* The Consumer class will use rd_kafka_conf_set_rebalance_cb and will handle the
|
|
* rebalance, converting from rdkafka topic partition list handles into vector<TopicPartition>
|
|
* and executing the assignment/revocation/rebalance_error callbacks.
|
|
*
|
|
* \note You *do not need* to call Consumer::assign with an empty topic partition list or
|
|
* anything like that. That's handled automatically by cppkafka. This is just a notifitation
|
|
* so your application code can react to revocations
|
|
*
|
|
* \param callback The topic/partition revocation callback
|
|
*/
|
|
void set_revocation_callback(RevocationCallback callback);
|
|
|
|
/**
|
|
* \brief Sets the rebalance error callback
|
|
*
|
|
* The Consumer class will use rd_kafka_conf_set_rebalance_cb and will handle the
|
|
* rebalance, converting from rdkafka topic partition list handles into vector<TopicPartition>
|
|
* and executing the assignment/revocation/rebalance_error callbacks.
|
|
*
|
|
* \param callback The rebalance error callback
|
|
*/
|
|
void set_rebalance_error_callback(RebalanceErrorCallback callback);
|
|
|
|
/**
|
|
* \brief Subscribes to the given list of topics
|
|
*
|
|
* This translates to a call to rd_kafka_subscribe
|
|
*
|
|
* \param topics The topics to subscribe to
|
|
*/
|
|
void subscribe(const std::vector<std::string>& topics);
|
|
|
|
/**
|
|
* \brief Unsubscribes to the current subscription list
|
|
*
|
|
* This translates to a call to rd_kafka_unsubscribe
|
|
*/
|
|
void unsubscribe();
|
|
|
|
/**
|
|
* \brief Sets the current topic/partition assignment
|
|
*
|
|
* This translates into a call to rd_kafka_assign
|
|
*/
|
|
void assign(const TopicPartitionList& topic_partitions);
|
|
|
|
/**
|
|
* \brief Unassigns the current topic/partition assignment
|
|
*
|
|
* This translates into a call to rd_kafka_assign using a null as the topic partition list
|
|
* parameter
|
|
*/
|
|
void unassign();
|
|
|
|
/**
|
|
* \brief Commits the given message synchronously
|
|
*
|
|
* This translates into a call to rd_kafka_commit_message
|
|
*
|
|
* \param msg The message to be committed
|
|
*/
|
|
void commit(const Message& msg);
|
|
|
|
/**
|
|
* \brief Commits the given message asynchronously
|
|
*
|
|
* This translates into a call to rd_kafka_commit_message
|
|
*
|
|
* \param msg The message to be committed
|
|
*/
|
|
void async_commit(const Message& msg);
|
|
|
|
/**
|
|
* \brief Commits the offsets on the given topic/partitions synchronously
|
|
*
|
|
* This translates into a call to rd_kafka_commit
|
|
*
|
|
* \param topic_partitions The topic/partition list to be committed
|
|
*/
|
|
void commit(const TopicPartitionList& topic_partitions);
|
|
|
|
/**
|
|
* \brief Commits the offsets on the given topic/partitions asynchronously
|
|
*
|
|
* This translates into a call to rd_kafka_commit
|
|
*
|
|
* \param topic_partitions The topic/partition list to be committed
|
|
*/
|
|
void async_commit(const TopicPartitionList& topic_partitions);
|
|
|
|
/**
|
|
* \brief Gets the minimum and maximum offsets for the given topic/partition
|
|
*
|
|
* This translates into a call to rd_kafka_get_watermark_offsets
|
|
*
|
|
* \param topic_partition The topic/partition to get the offsets from
|
|
*/
|
|
OffsetTuple get_offsets(const TopicPartition& topic_partition) const;
|
|
|
|
/**
|
|
* \brief Gets the offsets committed for the given topic/partition list
|
|
*
|
|
* This translates into a call to rd_kafka_committed
|
|
*
|
|
* \param topic_partitions The topic/partition list to be queried
|
|
*/
|
|
TopicPartitionList get_offsets_committed(const TopicPartitionList& topic_partitions) const;
|
|
|
|
/**
|
|
* \brief Gets the offset positions for the given topic/partition list
|
|
*
|
|
* This translates into a call to rd_kafka_position
|
|
*
|
|
* \param topic_partitions The topic/partition list to be queried
|
|
*/
|
|
TopicPartitionList get_offsets_position(const TopicPartitionList& topic_partitions) const;
|
|
|
|
/**
|
|
* \brief Gets the current topic subscription
|
|
*
|
|
* This translates to a call to rd_kafka_subscription
|
|
*/
|
|
std::vector<std::string> get_subscription() const;
|
|
|
|
/**
|
|
* \brief Gets the current topic/partition list assignment
|
|
*
|
|
* This translates to a call to rd_kafka_assignment
|
|
*/
|
|
TopicPartitionList get_assignment() const;
|
|
|
|
/**
|
|
* \brief Gets the group member id
|
|
*
|
|
* This translates to a call to rd_kafka_memberid
|
|
*/
|
|
std::string get_member_id() const;
|
|
|
|
/**
|
|
* Gets the partition assignment callback.
|
|
*/
|
|
const AssignmentCallback& get_assignment_callback() const;
|
|
|
|
/**
|
|
* Gets the partition revocation callback.
|
|
*/
|
|
const RevocationCallback& get_revocation_callback() const;
|
|
|
|
/**
|
|
* Gets the rebalance error callback.
|
|
*/
|
|
const RebalanceErrorCallback& get_rebalance_error_callback() const;
|
|
|
|
/**
|
|
* \brief Polls for new messages
|
|
*
|
|
* This will call rd_kafka_consumer_poll.
|
|
*
|
|
* Note that you need to call poll periodically as a keep alive mechanism, otherwise the broker
|
|
* will think this consumer is down and will trigger a rebalance (if using dynamic
|
|
* subscription).
|
|
*
|
|
* The timeout used on this call will be the one configured via Consumer::set_timeout.
|
|
*
|
|
* The returned message *might* be empty. If's necessary to check that it's a valid one before
|
|
* using it:
|
|
*
|
|
* \code
|
|
* Message msg = consumer.poll();
|
|
* if (msg) {
|
|
* // It's a valid message!
|
|
* }
|
|
* \endcode
|
|
*/
|
|
Message poll();
|
|
|
|
/**
|
|
* \brief Polls for new messages
|
|
*
|
|
* Same as the other overload of Consumer::poll but the provided timeout will be used
|
|
* instead of the one configured on this Consumer.
|
|
*
|
|
* \param timeout The timeout to be used on this call
|
|
*/
|
|
Message poll(std::chrono::milliseconds timeout);
|
|
private:
|
|
static void rebalance_proxy(rd_kafka_t *handle, rd_kafka_resp_err_t error,
|
|
rd_kafka_topic_partition_list_t *partitions, void *opaque);
|
|
|
|
void close();
|
|
void commit(const Message& msg, bool async);
|
|
void commit(const TopicPartitionList& topic_partitions, bool async);
|
|
void handle_rebalance(rd_kafka_resp_err_t err, TopicPartitionList& topic_partitions);
|
|
|
|
AssignmentCallback assignment_callback_;
|
|
RevocationCallback revocation_callback_;
|
|
RebalanceErrorCallback rebalance_error_callback_;
|
|
};
|
|
|
|
} // cppkafka
|
|
|
|
#endif // CPP_KAFKA_CONSUMER_H
|