Run R# lambda function in python workflow

Overview

This package enables seamless execution of R# lambda functions within Python workflows, supporting both local and Docker containerized environments. It handles configuration serialization, execution environment setup, and cross-platform compatibility.

Key Features

​

• Multi-Environment Execution​

  • Local Execution: Direct execution via .NET R# runtime ​ - Docker Execution: Containerized runs with automatic volume management

• ​Automatic Configuration​

  • Parameter serialization to .r_env/run.json
  • Runtime options serialization to .r_env/options.json

• Unified Interface​

  • Consistent API for local and containerized execution
  • Support for both dictionary and CLI-style arguments

Installation

pip install r-lambda

​

System Requirements:

• Python ≥3.8
• .NET Runtime (for local execution)
• Docker Engine (for containerized execution)

Core Concepts

Introduce the R# lambda

The R# lambda function is a kind of shell feature function in R# script host. Assuming that there is a function named hello_world in a R# package which is named demo, so that we could run this hello world function in R# script file:

# In package "demo"
# function inside package namespace: demo 
const hello_world = function(str) {
    print(`hello: ${str}!`);
}

# call function in another script file
demo::hello_world("world");

Via the R# lambda function feature, that we could run this function without write script file, and we could run this function from commandline directly, example as:

# call function via R# lambda
Rscript --lambda demo::hello_world

and the parameter value of hello world function will be setup via a runtime json file ./.r_env/run.json in the working directory:

{
    "str": "world" 
}

If the function invoke contains getOption function calls, then you could setup the runtime environment via the json file ./.r_env/options.json in the working directory:

{
    "example-var": "1234"
}

So, you could get such environment variable value in R# runtime environment by getOption:

print(getOption("example-var"));
# [1] "1234"

Configuration Files

API Reference

call_lambda(func, ​**kwargs)

​

Parameters:

Call R# lambda from a python workflow

For call a R# lambda function from your python workflow, then you could use this python package function. Current package call the R# workflow function running in local machine or running in a docker container already been wrapped into function calls, so that you can call such hello world function in R# package in python, example like:

import r_lambda
from r_lambda.docker import docker_image

r_lambda.call_lambda("demo::hello_world", 
argv = {"str": "world"}, 
    options = None,
    workdir = "./",
    docker = docker_image(id = "example_image", 
        volumn = ["/home"], name = "test"), 
    run_debug = False
)

Usage Examples

Basic Local Execution

from r_lambda import call_lambda

call_lambda(
    func="demo::hello_world",
    argv={"str": "world"},  # Dictionary-style arguments
    options={"verbose": True},
    workdir="./analysis"
)

CLI-Style Arguments

call_lambda(
    "stats::calculate",
    argv=["--input", "data.csv", "--threshold", "0.05"],  # CLI-style arguments
    options={"parallel": True}
)

Docker Execution

from r_lambda import call_lambda, docker_image

docker_config = docker_image(
    id="rsharp/runtime:3.2",
    volumn=["/data/inputs", "/data/outputs"],  # Absolute paths required
    shm_size="2g",
    name="analysis_container"
)

call_lambda(
    func="preprocess::clean_data",
    argv={"input_dir": "/data/inputs", "output_dir": "/data/outputs"},
    docker=docker_config
)

Advanced Configuration

Volume Mounting

The package automatically handles:

• Docker socket mounting (/var/run/docker.sock)
• /tmp directory sharing
• Argument-specified volumes from docker_image() ​ Example Mount:

docker_image(
    id="rsharp/runtime:3.2",
    volumn=["/host/path"],  # Mounts to /host/path in container
    ...
)

Runtime Options

Configure environment variables accessible via getOption() in R#:

options = {
    "max_memory": "16G",
    "temp_dir": "/tmp/rsharp",
    "threads": 8
}

Debugging & Testing

Dry-run Mode

call_lambda(
    func="demo::test",
    run_debug=True  # Prints command without execution
)

​Sample Output:

[DEBUG] Generated command:
docker run -v /data:/data ... rsharp/runtime:3.2 dotnet Rscript.dll --lambda demo::test

Configuration Inspection

Check generated files in workdir/.r_env:

• run.json: Serialized argv parameters
• options.json: Serialized runtime configuration

Best Practices

​

1. Path Handling​

• Use absolute paths for Docker volumes
• Avoid spaces in directory names
• Windows: Use raw strings for paths ("C:\data")

​2. Resource Allocation​

• Set shm_size for memory-intensive tasks
• Configure thread limits in options

​3. Container Management​

• Reuse containers for sequential calls
• Clean up temporary containers with --rm flag

Error Handling

​ Common Exit Codes:

License & Support

MIT License. Report issues at GitHub Repo.