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Pulsar C++ client

You can use Pulsar C++ client to create Pulsar producers and consumers in C++.

All the methods in producer, consumer, and reader of a C++ client are thread-safe.

Supported platforms​

Pulsar C++ client is supported on Linux and MacOS platforms.

Doxygen-generated API docs for the C++ client are available here.

System requirements​

You need to install the following components before using the C++ client:

Linux​

Compilation​

  1. Clone the Pulsar repository.

$ git clone https://github.com/apache/pulsar

  1. Install all necessary dependencies.

$ apt-get install cmake libssl-dev libcurl4-openssl-dev liblog4cxx-dev \
libprotobuf-dev protobuf-compiler libboost-all-dev google-mock libgtest-dev libjsoncpp-dev

  1. Compile and install Google Test.

# libgtest-dev version is 1.18.0 or above
$ cd /usr/src/googletest
$ sudo cmake .
$ sudo make
$ sudo cp ./googlemock/libgmock.a ./googlemock/gtest/libgtest.a /usr/lib/

# less than 1.18.0
$ cd /usr/src/gtest
$ sudo cmake .
$ sudo make
$ sudo cp libgtest.a /usr/lib

$ cd /usr/src/gmock
$ sudo cmake .
$ sudo make
$ sudo cp libgmock.a /usr/lib

  1. Compile the Pulsar client library for C++ inside the Pulsar repository.

$ cd pulsar-client-cpp
$ cmake .
$ make

After you install the components successfully, the files libpulsar.so and libpulsar.a are in the lib folder of the repository. The tools perfProducer and perfConsumer are in the perf directory.

Install Dependencies​

Since 2.1.0 release, Pulsar ships pre-built RPM and Debian packages. You can download and install those packages directly.

After you download and install RPM or DEB, the libpulsar.so, libpulsarnossl.so, libpulsar.a, and libpulsarwithdeps.a libraries are in your /usr/lib directory.

By default, they are built in code path ${PULSAR_HOME}/pulsar-client-cpp. You can build with the command below.

cmake . -DBUILD_TESTS=OFF -DLINK_STATIC=ON && make pulsarShared pulsarSharedNossl pulsarStatic pulsarStaticWithDeps -j 3.

These libraries rely on some other libraries. If you want to get detailed version of dependencies, see RPM or DEB files.

  1. libpulsar.so is a shared library, containing statically linked boost and openssl. It also dynamically links all other necessary libraries. You can use this Pulsar library with the command below.

g++ --std=c++11 PulsarTest.cpp -o test /usr/lib/libpulsar.so -I/usr/local/ssl/include

  1. libpulsarnossl.so is a shared library, similar to libpulsar.so except that the libraries openssl and crypto are dynamically linked. You can use this Pulsar library with the command below.

g++ --std=c++11 PulsarTest.cpp -o test /usr/lib/libpulsarnossl.so -lssl -lcrypto -I/usr/local/ssl/include -L/usr/local/ssl/lib

  1. libpulsar.a is a static library. You need to load dependencies before using this library. You can use this Pulsar library with the command below.

g++ --std=c++11 PulsarTest.cpp -o test /usr/lib/libpulsar.a -lssl -lcrypto -ldl -lpthread -I/usr/local/ssl/include -L/usr/local/ssl/lib -lboost_system -lboost_regex -lcurl -lprotobuf -lzstd -lz

  1. libpulsarwithdeps.a is a static library, based on libpulsar.a. It is archived in the dependencies of libboost_regex, libboost_system, libcurl, libprotobuf, libzstd and libz. You can use this Pulsar library with the command below.

g++ --std=c++11 PulsarTest.cpp -o test /usr/lib/libpulsarwithdeps.a -lssl -lcrypto -ldl -lpthread -I/usr/local/ssl/include -L/usr/local/ssl/lib

The libpulsarwithdeps.a does not include library openssl related libraries libssl and libcrypto, because these two libraries are related to security. It is more reasonable and easier to use the versions provided by the local system to handle security issues and upgrade libraries.

Install RPM​

  1. Download a RPM package from the links in the table.
LinkCrypto files
clientasc, sha512
client-debuginfoasc, sha512
client-develasc, sha512
  1. Install the package using the following command.

$ rpm -ivh apache-pulsar-client*.rpm

After you install RPM successfully, Pulsar libraries are in the /usr/lib directory.

Install Debian​

  1. Download a Debian package from the links in the table.
LinkCrypto files
clientasc, sha512
client-develasc, sha512
  1. Install the package using the following command.

$ apt install ./apache-pulsar-client*.deb

After you install DEB successfully, Pulsar libraries are in the /usr/lib directory.

Build​

If you want to build RPM and Debian packages from the latest master, follow the instructions below. You should run all the instructions at the root directory of your cloned Pulsar repository.

There are recipes that build RPM and Debian packages containing a statically linked libpulsar.so / libpulsarnossl.so / libpulsar.a / libpulsarwithdeps.a with all required dependencies.

To build the C++ library packages, you need to build the Java packages first.


mvn install -DskipTests

RPM​

To build the RPM inside a Docker container, use the command below. The RPMs are in the pulsar-client-cpp/pkg/rpm/RPMS/x86_64/ path.


pulsar-client-cpp/pkg/rpm/docker-build-rpm.sh

Package nameContent
pulsar-clientShared library libpulsar.so and libpulsarnossl.so
pulsar-client-develStatic library libpulsar.a, libpulsarwithdeps.aand C++ and C headers
pulsar-client-debuginfoDebug symbols for libpulsar.so

Debian​

To build Debian packages, enter the following command.


pulsar-client-cpp/pkg/deb/docker-build-deb.sh

Debian packages are created in the pulsar-client-cpp/pkg/deb/BUILD/DEB/ path.

Package nameContent
pulsar-clientShared library libpulsar.so and libpulsarnossl.so
pulsar-client-devStatic library libpulsar.a, libpulsarwithdeps.a and C++ and C headers

MacOS​

Compilation​

  1. Clone the Pulsar repository.

$ git clone https://github.com/apache/pulsar

  1. Install all necessary dependencies.

# OpenSSL installation
$ brew install openssl
$ export OPENSSL_INCLUDE_DIR=/usr/local/opt/openssl/include/
$ export OPENSSL_ROOT_DIR=/usr/local/opt/openssl/

# Protocol Buffers installation
$ brew tap homebrew/versions
$ brew install protobuf260
$ brew install boost
$ brew install log4cxx

# Google Test installation
$ git clone https://github.com/google/googletest.git
$ cd googletest
$ cmake .
$ make install

  1. Compile the Pulsar client library in the repository that you cloned.

$ cd pulsar-client-cpp
$ cmake .
$ make

Install libpulsar​

Pulsar releases are available in the Homebrew core repository. You can install the C++ client library with the following command. The package is installed with the library and headers.


brew install libpulsar

Connection URLs​

To connect Pulsar using client libraries, you need to specify a Pulsar protocol URL.

Pulsar protocol URLs are assigned to specific clusters, you can use the Pulsar URI scheme. The default port is 6650. The following is an example for localhost.


pulsar://localhost:6650

In a Pulsar cluster in production, the URL looks as follows.


pulsar://pulsar.us-west.example.com:6650

If you use TLS authentication, you need to add ssl, and the default port is 6651. The following is an example.


pulsar+ssl://pulsar.us-west.example.com:6651

Create a consumer​

To use Pulsar as a consumer, you need to create a consumer on the C++ client. The following is an example.


Client client("pulsar://localhost:6650");

Consumer consumer;
Result result = client.subscribe("my-topic", "my-subscription-name", consumer);
if (result != ResultOk) {
LOG_ERROR("Failed to subscribe: " << result);
return -1;
}

Message msg;

while (true) {
consumer.receive(msg);
LOG_INFO("Received: " << msg
<< " with payload '" << msg.getDataAsString() << "'");

consumer.acknowledge(msg);
}

client.close();

Create a producer​

To use Pulsar as a producer, you need to create a producer on the C++ client. The following is an example.


Client client("pulsar://localhost:6650");

Producer producer;
Result result = client.createProducer("my-topic", producer);
if (result != ResultOk) {
LOG_ERROR("Error creating producer: " << result);
return -1;
}

// Publish 10 messages to the topic
for (int i = 0; i < 10; i++){
Message msg = MessageBuilder().setContent("my-message").build();
Result res = producer.send(msg);
LOG_INFO("Message sent: " << res);
}
client.close();

Enable authentication in connection URLs​

If you use TLS authentication when connecting to Pulsar, you need to add ssl in the connection URLs, and the default port is 6651. The following is an example.


ClientConfiguration config = ClientConfiguration();
config.setUseTls(true);
config.setTlsTrustCertsFilePath("/path/to/cacert.pem");
config.setTlsAllowInsecureConnection(false);
config.setAuth(pulsar::AuthTls::create(
"/path/to/client-cert.pem", "/path/to/client-key.pem"););

Client client("pulsar+ssl://my-broker.com:6651", config);

For complete examples, refer to C++ client examples.

Schema​

This section describes some examples about schema. For more information about schema, see Pulsar schema.

Create producer with Avro schema​

The following example shows how to create a producer with an Avro schema.


static const std::string exampleSchema =
"{\"type\":\"record\",\"name\":\"Example\",\"namespace\":\"test\","
"\"fields\":[{\"name\":\"a\",\"type\":\"int\"},{\"name\":\"b\",\"type\":\"int\"}]}";
Producer producer;
ProducerConfiguration producerConf;
producerConf.setSchema(SchemaInfo(AVRO, "Avro", exampleSchema));
client.createProducer("topic-avro", producerConf, producer);

Create consumer with Avro schema​

The following example shows how to create a consumer with an Avro schema.


static const std::string exampleSchema =
"{\"type\":\"record\",\"name\":\"Example\",\"namespace\":\"test\","
"\"fields\":[{\"name\":\"a\",\"type\":\"int\"},{\"name\":\"b\",\"type\":\"int\"}]}";
ConsumerConfiguration consumerConf;
Consumer consumer;
consumerConf.setSchema(SchemaInfo(AVRO, "Avro", exampleSchema));
client.subscribe("topic-avro", "sub-2", consumerConf, consumer)