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wlan-cloud-lib-cppkafka/include/cppkafka/queue.h
2020-10-18 12:30:27 +01:00

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/*
* 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.
*
*/
#include <vector>
#include <memory>
#include <librdkafka/rdkafka.h>
#include "event.h"
#include "macros.h"
#include "message.h"
#ifndef CPPKAFKA_QUEUE_H
#define CPPKAFKA_QUEUE_H
namespace cppkafka {
/**
* \brief Represents a rdkafka queue
*
* This is a simple wrapper over a rd_kafka_queue_t*
*/
class CPPKAFKA_API Queue {
public:
/**
* \brief Creates a Queue object that doesn't take ownership of the handle
*
* \param handle The handle to be used
*/
static Queue make_non_owning(rd_kafka_queue_t* handle);
/**
* \brieef Creates a Queue object out of a handle.
*
* This will check what the rdkafka version is and will return either an owned
* queue handle or a non owned one, depending on whether the current version
* is >= RD_KAFKA_QUEUE_REFCOUNT_BUG_VERSION (see macros.h)
*
* \param handle The handle to be used
*/
static Queue make_queue(rd_kafka_queue_t* handle);
/**
* \brief Constructs an empty queue
*
* Note that using any methods except Queue::get_handle on an empty queue is undefined
* behavior
*/
Queue();
/**
* \brief Constructs a queue using a handle
*
* This will take ownership of the handle
*
* \param handle The handle to be used
*/
Queue(rd_kafka_queue_t* handle);
/**
* Returns the rdkakfa handle
*/
rd_kafka_queue_t* get_handle() const;
/**
* \brief Returns the length of the queue
*
* This translates to a call to rd_kafka_queue_length
*/
size_t get_length() const;
/**
* \brief Forward to another queue
*
* This translates to a call to rd_kafka_queue_forward
*/
void forward_to_queue(const Queue& forward_queue) const;
/**
* \brief Disable forwarding to another queue
*
* This translates to a call to rd_kafka_queue_forward(NULL)
*/
void disable_queue_forwarding() const;
/**
* \brief Sets the timeout for consume operations
*
* This timeout is applied when calling consume()
*
* \param timeout The timeout to be set
*/
void set_timeout(std::chrono::milliseconds timeout);
/**
* Gets the configured timeout.
*
* \sa Queue::set_timeout
*/
std::chrono::milliseconds get_timeout() const;
/**
* \brief Consume a message from this queue
*
* This translates to a call to rd_kafka_consume_queue using the configured timeout for this object
*
* \return A message
*/
Message consume() const;
/**
* \brief Consume a message from this queue
*
* Same as consume() but the specified timeout will be used instead of the configured one
*
* \param timeout The timeout to be used on this call
*
* \return A message
*/
Message consume(std::chrono::milliseconds timeout) const;
/**
* \brief Consumes a batch of messages from this queue
*
* This translates to a call to rd_kafka_consume_batch_queue using the configured timeout
* for this object
*
* \param max_batch_size The max number of messages to consume if available
* \param alloc The optionally supplied allocator for the message list
*
* \return A list of messages. Could be empty if there's nothing to consume
*/
template <typename Allocator>
std::vector<Message, Allocator> consume_batch(size_t max_batch_size,
const Allocator& alloc) const;
/**
* \brief Consumes a batch of messages from this queue
*
* This translates to a call to rd_kafka_consume_batch_queue using the configured timeout
* for this object
*
* \param max_batch_size The max number of messages to consume if available
*
* \return A list of messages. Could be empty if there's nothing to consume
*/
std::vector<Message> consume_batch(size_t max_batch_size) const;
/**
* \brief Consumes a batch of messages from this queue
*
* Same as Queue::consume_batch(size_t) but the specified timeout will be used instead of the
* configured one
*
* \param max_batch_size The max number of messages to consume if available
* \param timeout The timeout to be used on this call
* \param alloc The optionally supplied allocator for the message list
*
* \return A list of messages. Could be empty if there's nothing to consume
*/
template <typename Allocator>
std::vector<Message, Allocator> consume_batch(size_t max_batch_size,
std::chrono::milliseconds timeout,
const Allocator& alloc) const;
/**
* \brief Consumes a batch of messages from this queue
*
* Same as Queue::consume_batch(size_t) but the specified timeout will be used instead of the
* configured one
*
* \param max_batch_size The max number of messages to consume if available
* \param timeout The timeout to be used on this call
*
* \return A list of messages. Could be empty if there's nothing to consume
*/
std::vector<Message> consume_batch(size_t max_batch_size,
std::chrono::milliseconds timeout) const;
/**
* \brief Extracts the next message in this Queue
*
* /return The latest event, if any
*/
Event next_event() const;
/**
* \brief Extracts the next message in this Queue
*
* \param timeout The amount of time to wait for this operation to complete
*
* /return The latest event, if any
*/
Event next_event(std::chrono::milliseconds timeout) const;
/**
* Indicates whether this queue is valid (not null)
*/
explicit operator bool() const {
return handle_ != nullptr;
}
private:
static const std::chrono::milliseconds DEFAULT_TIMEOUT;
using HandlePtr = std::unique_ptr<rd_kafka_queue_t, decltype(&rd_kafka_queue_destroy)>;
struct NonOwningTag { };
Queue(rd_kafka_queue_t* handle, NonOwningTag);
// Members
HandlePtr handle_;
std::chrono::milliseconds timeout_ms_;
};
using QueueList = std::vector<Queue>;
template <typename Allocator>
std::vector<Message, Allocator> Queue::consume_batch(size_t max_batch_size,
const Allocator& alloc) const {
return consume_batch(max_batch_size, timeout_ms_, alloc);
}
template <typename Allocator>
std::vector<Message, Allocator> Queue::consume_batch(size_t max_batch_size,
std::chrono::milliseconds timeout,
const Allocator& alloc) const {
std::vector<rd_kafka_message_t*> raw_messages(max_batch_size);
ssize_t result = rd_kafka_consume_batch_queue(handle_.get(),
static_cast<int>(timeout.count()),
raw_messages.data(),
raw_messages.size());
if (result == -1) {
rd_kafka_resp_err_t error = rd_kafka_last_error();
if (error != RD_KAFKA_RESP_ERR_NO_ERROR) {
throw QueueException(error);
}
return std::vector<Message, Allocator>(alloc);
}
// Build message list
return std::vector<Message, Allocator>(raw_messages.begin(), raw_messages.begin() + result, alloc);
}
} // cppkafka
#endif //CPPKAFKA_QUEUE_H