influxdb-cpp-rest

A modern C++20 InfluxDB client via C++ REST SDK + a C wrapper of the asynchronous API as a shared library.

C++ Standard Requirements

This project requires C++20 or later.

• Minimum compiler versions:
  • GCC 11+
  • Clang 14+
  • MSVC 2019+ (19.29+) with /std:c++20 or later
• The project uses C++20
• All dependencies are C++20 compatible
• Note: The legacy C++03 version is available in the v0.0.1-legacy tag

See the demo source for the current api example.

The unbatched approach (and without connection reuse) may not be sufficient in some situations, as without batching, about 200 lines/sec can be inserted.

An async batching api targets thousands inserts per second. Behind the scenes, the API uses RxCpp and cppformat.

Status

• Modern C++20 build system with CMake and Conan
• CI/CD with GitHub Actions (Linux, macOS, Windows)
• Tested with InfluxDB v1.8+

Synchronous insertion

using namespace influxdb::api;
using namespace std::string_literals;

auto db = simple_db("http://localhost:8086"s, "my_db"s);
db.insert(
    line("log"s,
         key_value_pairs("my_tag"s, 42L),
         key_value_pairs("value"s, "hello world!"s)));

Asynchronous insertion

The asynchronous API inserts the points on an active object with automatic batching, thus increasing throughput.

using namespace influxdb::api;  // For line, key_value_pairs
using namespace std::string_literals;
using async_db = influxdb::async_api::simple_db;  // Type alias to avoid ambiguity

auto db = async_db("http://localhost:8086"s, "my_db"s);

for (auto i = 0; i < 123456; ++i) {
    db.insert(
        line(
            "my_measurements"s,
            key_value_pairs("my_count"s, i % MAX_VALUES_PER_TAG),
            key_value_pairs("value"s, "hi!"s)
        )
    );
}

C API

see async_c_test.cpp and the related headers.

Timestamps

Timestamps can be added as the last parameter to the line constructor, and only need to return a serializable value on TTimestamp::now(). There is a default std::chrono-based implementation:

using namespace influxdb::api;
using namespace std::string_literals;

line(
    "my_measurements"s,
    key_value_pairs("my_count"s, 42),
    key_value_pairs("value"s, "hi!"s),
    default_timestamp()  // Optional: uses std::chrono for timestamps
)

MAX_VALUES_PER_TAG for demo purposes here, as there is such a maximum and it has to be observed by the clients.

Multiple lines in synchronous API

Add lines using the () operator on the line:

using namespace influxdb::api;
using namespace std::string_literals;

line
    ("multiple"s, key_value_pairs("v1"s, 1), key_value_pairs())
    ("multiple"s, key_value_pairs("v2"s, 2), key_value_pairs())

Query

using namespace influxdb::raw;
using namespace std::string_literals;

auto db = db_utf8("http://localhost:8086"s, "my_db"s);
auto query = "select count(*) from my_db..my_measurements"s;
auto json_response = db.get(query);

↓

{"results":[{"series":[{"name":"asynctest","columns":["time","count_value"],"values":[["...Z",123456]]}]}]}

Authentication

Basic authentication can be used with all API variants:

using namespace influxdb::raw;
using namespace std::string_literals;

auto db = db_utf8("http://localhost:8086"s, "my_db"s);
db.with_authentication("username"s, "password"s);
auto response = db.get("select * from my_measurements");

Error Handling

• Synchronous C++ API will throw exceptions on HTTP errors
• Asynchronous APIs will drop inserts on HTTP errors and print to stderr
• C api tries to catch CPP exceptions and
  • print exceptions to stderr
  • return non-zero int or nullptr where sensible
• Open issue: #18

Build & Test

Prerequisites

• CMake 3.20+
• Conan 2.0+
• C++20 compatible compiler
• Python 3.x (for Conan)
• Docker (for running tests)

Quick Development Workflow

# 1. Install Conan (one-time setup)
pip install conan

# 2. Build the library
./scripts/build.sh Release        # Linux/macOS
# or
scripts\build.bat Release         # Windows

# 3. Start InfluxDB for testing
./scripts/start-influxdb.sh       # Linux/macOS
# or
scripts\start-influxdb.bat         # Windows

# 4. Run tests
./scripts/test.sh                  # Linux/macOS
# or
scripts\test.bat                   # Windows

# 5. Stop InfluxDB when done
./scripts/stop-influxdb.sh        # Linux/macOS
# or
scripts\stop-influxdb.bat         # Windows

Using docker compose directly:

# Linux/macOS
docker compose up -d              # Start InfluxDB
docker compose down               # Stop InfluxDB

# Windows
docker compose -f docker-compose.win.yml up -d    # Start InfluxDB
docker compose -f docker-compose.win.yml down     # Stop InfluxDB

For detailed development instructions, see docs/development.md.

Thanks to

• @kirkshoop for indispensable help with RxCpp
• @nikkov for pointing out the missing essential features
• @promgamer, @garaemon for the identifiers PRs

License