Drea

A C++17 framework for CLI apps and services. Declare commands and options once in YAML; Drea derives the rest.

Features

• Commands and subcommands (with argument validation)
• Options (typed, validated, with short forms)
• Configuration from multiple sources (file, env, flags, AWS Secrets Manager)
• Logging (spdlog-based, with optional Graylog sink)
• --help rendering with a dynamic footer hook
• Command groups for tier/role-based gating of help, completion, and execution
• man page generation
• Shell completion (bash, zsh, fish)

A 30-second example

commands.yml:

app: say
version: 0.0.1
description: Prints the argument of the command "this" and quits.
options:
  - option: reverse
    description: reverse string
commands:
  - command: this
    params-names: string
    description: prints the argument
    local-options:
      - reverse

main.cpp:

#include <drea/core/Core>
#include <algorithm>
#include "commands.yml.h"

int main( int argc, char * argv[] )
{
    drea::core::App app( argc, argv );

    app.parse( std::string( commands_yml, commands_yml + commands_yml_len ) );
    app.commander().run( [ &app ]( const std::string & cmd ){
        if( cmd == "this" ){
            std::string say = app.commander().arguments().front();
            if( app.config().used( "reverse" ) ){
                std::reverse( say.begin(), say.end() );
            }
            app.logger().info( "{}", say );
        }
    });
}

$ ./say this hello
[2019-04-16 09:44:44.649] [say] [info] hello
$ ./say this hello --reverse
[2019-04-16 09:44:44.690] [say] [info] olleh

Build

Drea ships CMake presets (CMake >= 3.21 + Ninja). Point VCPKG_ROOT at your vcpkg checkout, then:

cmake --preset debug
cmake --build --preset debug
ctest --preset debug

Available presets: debug, release, sdk, debug-system, release-system, sdk-system. The *-system variants use system-installed dependencies instead of vcpkg.

Opt-in vcpkg features:

cmake --preset debug -DVCPKG_MANIFEST_FEATURES=toml        # TOML config files
cmake --preset debug -DVCPKG_MANIFEST_FEATURES=aws         # AWS Secrets Manager
cmake --preset debug -DVCPKG_MANIFEST_FEATURES="toml;aws"

To enable AWS Secrets Manager at runtime, pass -DENABLE_AWS=ON.

Bare configure (no preset) also works:

cmake -S . -B build
cmake --build build
ctest --test-dir build --output-on-failure

Use Drea in your project

find_package(drea REQUIRED)
target_link_libraries(main PRIVATE drea)

Documentation

• Commands — anatomy, parameters, hierarchy, hiding, groups
• Configuration — options, sources, evaluation order, sensitive values
• Help and shell integration — --help, dynamic footer, man, completion
• API reference — App, Commander, Config, Command, Option
• Examples — index of examples/

Quality

To run the SonarQube scan locally, install build-wrapper and sonar-scanner, set SONAR_TOKEN, reconfigure CMake (so it picks up sonar-scanner), and:

cmake --build build --target sonarqube

Further reading

• Command-line syntax: some basic concepts
• Man pages
• On formats

Similar libraries: Cobra (Go), Viper (Go), CLI11, cpp_cli.