CAPIO-CL — Cross-Application Programmable I/O Coordination Language

Platform support

OS / Arch
	YES	YES	YES
	YES	YES	N.A.

Documentation

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CAPIO-CL is a novel I/O coordination language that enables users to annotate file-based workflow data dependencies with synchronization semantics for files and directories. Designed to facilitate transparent overlap between computation and I/O operations, CAPIO-CL allows multiple producer–consumer application modules to coordinate efficiently using a JSON-based syntax.

For detailed documentation and examples, please visit:

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Overview

The CAPIO Coordination Language (CAPIO-CL) allows applications to declare:

• Data objects, I/O dependencies, and access modes
• Synchronization semantics across different processes
• Commit policies for I/O objects

At runtime, CAPIO-CL’s parser and engine components analyze, track, and manage these declared relationships, enabling * transparent data sharing* and cross-application optimizations.

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Building

Requirements & dependencies

• C++17 or greater
• Cmake 3.15 or newer
• Python3 to bundle CAPIO-CL json schemas into target binaries
• danielaparker/jsoncons to parse, serialize and validate CAPIO-CL JSON config files
• GoogleTest for automated testing
• pybind11 when building python wheels

jsoncons, GoogleTest and pybind11 are fetched automatically by CMake — no manual setup required.

Steps

Clone
git clone https://github.com/High-Performance-IO/CAPIO-CL.git


mkdir -p CAPIO-CL/build && cd CAPIO-CL/build
cmake ..
make 

By default, this will:

• Build the "libcapio_cl" static library
• Build the "CAPIO_CL_tests" executable (GoogleTest-based)
• Build the "py_capio_cl" python bindings (pybind11)

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Integration as a Subproject

CAPIO-CL can be included directly into another CMake project using:

include(FetchContent)

#####################################
# External projects
#####################################
FetchContent_Declare(
        capio_cl
        GIT_REPOSITORY https://github.com/High-Performance-IO/CAPIO-CL.git
        GIT_TAG main
)
FetchContent_MakeAvailable(capio_cl)

#####################################
# Include files and directories
#####################################
target_include_directories(${TARGET_NAME} PRIVATE
        ${capio_cl_SOURCE_DIR}
)

#####################################
# Link libraries
#####################################
target_link_libraries(${PROJECT_NAME} PRIVATE
        libcapio_cl
)

When included this way, unit tests and python bindings are not built, keeping integration clean for external projects.

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Python Bindings

CAPIO-CL now provides native Python bindings built using pybind11.
These bindings expose the core C++ APIs (Engine, Parser and Serializer), directly to Python, allowing the CAPIO-CL logic to be used within python projects.

Install from PyPI

CAPIO-CL is available on PyPI! Simply run

pip install py_capio_cl

Building the Bindings

You can build and install the Python bindings directly from the CAPIO-CL source tree using:

pip install --upgrade pip
pip install -r build-requirements.txt
python -m build
pip install dst/*.whl

This will build the Python wheel and install it into your current environment using an ad-hoc build environment, which is downloaded, installed, and configured in isolation. A faster way to build and install CAPIO-CL is to use native system packages and then run from within the CAPIO-CL root directory:

pip install .

This assumes that all build dependencies not fetched by cmake are available.

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API Snapshot

A simplified example of CAPIO-CL usage in C++:

#include "capiocl.hpp"

int main() {
    capiocl::Engine engine;
    engine.newFile("Hello_World.txt")
    engine.print();
    
    // Dump engine to configuration file
    capiocl::Serializer::dump(engine, "my_workflow", "my_workflow.json")
    return 0;
}

The py_capio_cl module provides access to CAPIO-CL’s core functionality through a high-level Python interface.

from py_capio_cl import Engine, Serializer

engine = Engine()
engine.newFile("Hello_World.txt")
engine.print()

# Dump engine to configuration file
Serializer.dump(engine, "my_workflow", "my_workflow.json")

CapioCL Web API Documentation

This section describes the REST-style Web API exposed by the CapioCL Web Server. The server provides HTTP endpoints for configuring and querying the CapioCL engine at runtime. Within the bruno_webapi_tests you can find several tests and examples on how to perform requests to the API webserver using bruno.

All endpoints communicate using JSON over HTTP. To enable the webserver, users needs to explicitly start it with:

capiocl::engine::Engine engine();

// start engine with default parameters
engine.startApiServer();

// or by specifying the address and port:
engine.startApiServer("127.0.0.1", 5520);

or equivalently in python with:

engine = py_capio_cl.Engine()

#start engine with default parameters
engine.startApiServer()

# or by specifying the address and port:
engine.startApiServer("127.0.0.1", 5520)

By default, the webserver listens only on local connection at the following address: 127.0.0.1:5520. No authentication services are currently available, and as such, users should put particular care when allowing connections from external endpoints.

Notes

• All GET endpoints expect a JSON body containing the targeted file path.
• The API is intended for local control and orchestration, not public exposure.

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Developing team

Name	Role	Contact
Marco Edoardo Santimaria	Designer and Maintainer	email | Homepage
Iacopo Colonnelli	Workflows Expert and Designer	email | Homepage
Massimo Torquati	Designer	email | Homepage
Marco Aldinucci	Designer	email | Homepage

Former Members

Name	Role	Contact
Alberto Riccardo Martinelli	Designer	email | Homepage