meco

MEga COnstellation emulator

Meco is a gRPC-based application that simulates and manages a Low Earth Orbit (LEO) Mega Constellation. It provides a command-line interface (CLI) to:

• Start a background gRPC server (on)
• Stop the server (off)
• Send a resource descriptor file to the server (start)

Features

• Manage a gRPC server via CLI
• Supports daemonized execution
• Implements structured logging using Python's logging module
• Supports auto-completion with argcomplete
• Uses gRPC for communication

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Installation

Install Dependencies

pip install argcomplete grpcio grpcio-tools

Enable CLI Auto-Completion

For Bash users:

eval "$(register-python-argcomplete meco)"

For global auto-completion (one-time setup):

activate-global-python-argcomplete

Compile gRPC Protocol Buffers

Ensure you have the meco.proto file and run:

python -m grpc_tools.protoc -I. --python_out=. --grpc_python_out=. meco.proto

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Usage

Start the gRPC Server (Daemon Mode)

python meco.py on

Runs the server in the background and stores its PID in /tmp/meco_server.pid.

Stop the gRPC Server

python meco.py off

Stops the server by terminating the background process.

Send a Resource Descriptor File

python meco.py start config.json

Sends config.json to the gRPC server for processing.

Show Help Menu

python meco.py --help

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Example Commands

Start the Server

python meco.py on

Output:

2025-02-07 12:00:00 [INFO] Meco server turned ON in background (PID: 12345).

Stop the Server

python meco.py off

Output:

2025-02-07 12:05:00 [INFO] Turning OFF Meco server (PID: 12345)...
2025-02-07 12:05:01 [INFO] Meco server turned OFF.

Send a Resource File

python meco.py start my_config.json

If the file exists:

2025-02-07 12:10:00 [INFO] Successfully started with resource file: my_config.json

If the file is missing:

2025-02-07 12:10:05 [ERROR] Error: File 'my_config.json' does not exist.

Check Available Commands

python meco.py --help

Output:

usage: meco [-h] {on,off,start} ...

Emulates a LEO Mega Constellation

positional arguments:
  {on,off,start}  Available commands
    on            Turn the Meco gRPC server ON (daemon mode)
    off           Turn the Meco gRPC server OFF
    start         Send a resource descriptor file to the Meco server

optional arguments:
  -h, --help      show this help message and exit

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Logging

Meco uses Python's logging module for structured logs.

Log levels used:

• INFO → General information (logger.info())
• WARNING → Server status (logger.warning())
• ERROR → Issues (logger.error())

Example Logs

2025-02-07 12:00:00 [INFO] Meco server started on port 50051.
2025-02-07 12:05:30 [INFO] Start() called with resource descriptor file: config.json
2025-02-07 12:06:10 [ERROR] Error: File 'config.json' does not exist.

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Development Setup

1. Clone the Repository

git clone https://github.com/your-repo/meco.git
cd meco

2. Set Up a Python Virtual Environment

It is recommended to use a virtual environment to isolate dependencies.

Create and Activate the Virtual Environment:

For Linux/macOS:

python3 -m venv venv
source venv/bin/activate

For Windows:

python -m venv venv
venv\Scripts\activate

Install Dependencies:

pip install -r requirements.txt

Verify Installation:

python -m grpc_tools.protoc --version

3. Compile gRPC Stubs

python -m grpc_tools.protoc -I. --python_out=. --grpc_python_out=. meco.proto

4. Run the Server in Debug Mode

python meco.py on

5. Run the Client for Testing

python meco.py start test.json

6. Deactivate the Virtual Environment (When Done)

deactivate

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Troubleshooting

"server already running" message when running python meco.py on

Check if the PID file exists:

cat /tmp/meco_server.pid

Manually stop the process:

kill -9 $(cat /tmp/meco_server.pid)
rm /tmp/meco_server.pid

"File does not exist" error when running python meco.py start file.json

Ensure the file exists:

ls -lh file.json

Command completion is not working

Re-enable argcomplete:

eval "$(register-python-argcomplete meco)"

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License

This project is licensed under the Apache License 2.0. See the LICENSE file for details.

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Future Improvements

• Add Docker support for containerized deployment
• Add unit tests for CLI and gRPC services

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Contributors

• Stefano Salsano - Maintainer