mpacklog.cpp

Log dictionaries to MessagePack files in C++.

Installation

Add a git repository rule to your Bazel WORKSPACE:

load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")

http_archive(
    name = "mpacklog",
    sha256 = "389cbd249607f1d0a2bbf6d11cbf0690604966e29a8e75e50160cf0faab068c7",
    strip_prefix = "mpacklog.cpp-3.1.0",
    url = "https://github.com/upkie/mpacklog.cpp/archive/refs/tags/v3.1.0.tar.gz",
)

load("@mpacklog//tools/workspace:default.bzl", add_mpacklog_repositories = "add_default_repositories")

# This adds dependencies such as @palimpsest for building mpacklog targets
add_mpacklog_repositories()

You can then use the @mpacklog dependency in your C++ targets.

Usage

The library is multi-threaded. Add messages to the log using the put function, they will be written to file in the background.

#include <mpacklog/Logger.h>
#include <palimpsest/Dictionary.h>

int main() {
    mpacklog::Logger logger("output.mpack");

    for (unsigned bar = 0; bar < 1000u; ++bar) {
        palimpsest::Dictionary dict;
        dict("foo") = bar;
        dict("something") = "else";
        logger.put(dict):
    }
}

See also

• mpacklog.py: Sibling Python project with an mpacklog command-line tool to manipulate MessagePack files.
• jq: manipulate JSON series to add, remove or extend fields.
• rq: transform from/to MessagePack, JSON, YAML, TOML, ...