Milvus C++ SDK

The C++ SDK for Milvus.

To contribute, read the contribution guidelines and the Development Guide.

Compatibility

The following table lists the recommended Milvus C++ SDK version for each Milvus release line:

Milvus version	Recommended SDK version
2.3.x	2.3 branch
2.4.x	v2.4.1
2.5.x	v2.5.4
2.6.x	v2.6.6
3.0.x	v3.0.2

Build from source

These commands build the SDK repository from source. If you want to consume the SDK from an application, see Use the SDK in your project or start with the tutorials.

Prerequisites

• C++14-capable compiler: GCC 9.4+ on Linux (GCC 9.4.0 is the oldest version currently tested in CI), Clang 5+, or MSVC 2017+
• CMake 3.16+
• Python 3 with pip (for Conan and build tools)

Quick start

git clone https://github.com/milvus-io/milvus-sdk-cpp.git
cd milvus-sdk-cpp
bash scripts/install_deps.sh
make

Build and run tests

make test          # unit tests + integration tests
make st            # system tests (requires Docker)
make coverage      # code coverage report

Install the SDK

make install       # install to /usr/local

Or specify a custom install prefix:

make install CMAKE_INSTALL_PREFIX=/path/to/install

Build with Conan

The project uses Conan 2 to manage dependencies. scripts/build.sh handles Conan integration automatically. You can also invoke Conan and CMake directly:

conan install . --build=missing -s build_type=Release
cmake --preset conan-release
cmake --build build/Release

See the Development Guide for details.

Use the SDK in your project

Choose the client API

New applications should use MilvusClientV2, which provides the current request/response-style API. The original MilvusClient API is retained for compatibility with existing applications and is in maintenance mode.

Link with CMake

After installing the SDK, consume its exported CMake package and target:

cmake_minimum_required(VERSION 3.16)
project(milvus_quickstart LANGUAGES CXX)

set(CMAKE_CXX_STANDARD 14)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(milvus_sdk CONFIG REQUIRED)

add_executable(milvus_quickstart main.cpp)
target_link_libraries(milvus_quickstart PRIVATE milvus_sdk::milvus_sdk)

If the SDK was installed to a custom prefix, provide it when configuring your project:

cmake -S . -B build -DCMAKE_PREFIX_PATH=/path/to/install
cmake --build build

The same find_package(milvus_sdk) call and milvus_sdk::milvus_sdk target are available when consuming the SDK as a Conan package.

For complete integration projects, see milvus-sdk-cpp-example. It demonstrates three supported approaches:

• without-conan: build the SDK and its dependencies from source with CMake/FetchContent
• conan-for-dependencies: build the SDK from source while Conan provides its dependencies
• conan-managed: consume the SDK itself as a Conan package

Minimal MilvusClientV2 program

The following program connects to Milvus and then closes the connection:

#include <iostream>

#include "milvus/MilvusClientV2.h"

int
main() {
    auto client = milvus::MilvusClientV2::Create();

    auto status = client->Connect(milvus::ConnectParam("http://localhost:19530"));
    if (!status.IsOk()) {
        std::cerr << "Failed to connect to Milvus: " << status.Message() << std::endl;
        return 1;
    }

    client->Disconnect();
    return 0;
}

This program expects Milvus at http://localhost:19530. For an independently buildable project that covers collection creation, insertion, loading, search, and cleanup, follow Tutorial 1: Quickstart.

Tutorials

Standalone CMake/Conan projects are available under tutorial. They consume the published C++ SDK as an application dependency and provide a beginner-to-advanced sequence.

For a first run, start with the quickstart. It demonstrates the complete connect, create, insert, load, search, and cleanup flow:

1. Quickstart
2. Collections
3. Schemas
4. Indexes
5. DML
6. DQL
7. Databases (advanced)
8. RBAC (advanced)

Each tutorial is an independent project with its own CMakeLists.txt, conanfile.py, and Makefile. Its README contains prerequisites, configuration, build/run commands, expected output, and troubleshooting guidance. See the tutorial index for shared Conan and connection settings.

Repository maintainers can build all tutorials against the current checkout and run one without changing directories:

make tutorials
make run-tutorial quickstart

More examples

This repository includes additional runnable examples under examples. New applications should start with the MilvusClientV2 examples in examples/src/v2.

Build an example and run it from the repository root using its source basename:

cmake --build cmake_build --target sdk_simple_v2 -j4
make run simple

make run simple runs cmake_build/examples/v2/sdk_simple_v2. Replace simple with another V2 example name such as general, dml, or hybrid_search. Examples connect to Milvus and may create, modify, or remove data; review the selected example and its connection settings first.

License

Apache License 2.0