Seqript (Sequence + Script)

A lightweight framework for executing structured scripts with nested operations.

Features

• Define scripts as nested JSON structures
• Register custom engines for different operations
• Environment variable expansion support
• Sequential and parallel execution modes
• Extensible through engine contributions

Documentation

• Quick Start
• Usage Guide
• Project Structure

Installation

pip install seqript (TODO: Add actual installation method)

Example

{
  "seq": [
    {"comment": "Starting operations"},
    {"sleep": 1},
    {"par": [
      {"cmd": ["echo", "Task 1"]},
      {"cmd": ["echo", "Task 2"]}
    ]}
  ]
}

Project Structure

Core Components

• Seqript: Main class that parses and executes scripts
• Engines: Modular operations (cmd, seq, par, etc.)
• Variable Expansion: ${var} substitution system

File Organization

seqript/
├── init.py
├── seqript.py # Main class
├── util/
│   └── expand_variable.py
└── engine/
    ├── init.py
    ├── cmd.py # Command execution
    ├── nop.py # No operation
    ├── par.py # Parallel execution
    ├── seq.py # Sequential execution
    └── contrib/ # Additional engines
        ├── sleep.py
        └── comment.py

Extension Points

1. Add engines to engine/contrib/
2. Override default engines during initialization
3. Extend variable expansion patterns## Extension Points

Usage Guide

Script Structure

Scripts are JSON objects where each key represents an engine:

{
  "engine_name": engine_specific_configuration
}

Environment Variables

Use ${VAR} syntax in strings for variable expansion:

{
  "cmd": ["echo", "${MESSAGE}"],
  "env": {"MESSAGE": "Hello"}
}

Custom Engines

Register additional engines during initialization:

from seqript import Seqript

def custom_engine(seqript, **kwargs):
    print(f"Custom engine called with {kwargs}")

seqript = Seqript(engines={
    "custom": custom_engine,
    **Seqript._DEFAULT_ENGINES
})

Quick Start

Basic Usage

1. Create a script file (example.json):

{
  "seq": [
    {"comment": "My first script"},
    {"sleep": 2},
    {"cmd": ["echo", "Hello World"]}
  ]
}

2. Execute it:

from seqript import Seqript

seqript = Seqript(name="example")
with open("example.json") as f:
    seqript(**json.load(f))

Available Engines

• seq: Sequential execution
• par: Parallel execution
• cmd: Command execution
• nop: No operation
• sleep: Delay execution
• comment: Print message