---
title: Process Management Component
description: Documentation for the process management component in Raxol Terminal Emulator
date: 2023-04-04
author: Raxol Team
section: components
tags: [process, terminal, documentation]
---

# Process Management Component

The process management component handles terminal process creation, monitoring, and control.

## Features

- Process creation and execution
- Process monitoring
- Process termination
- Signal handling
- Environment variables
- Working directory management
- Process groups
- Job control
- Process priority
- Resource limits

## Usage

```elixir
# Create a new process manager
processes = Raxol.Terminal.Processes.new()

# Start a new process
{:ok, pid} = Raxol.Terminal.Processes.spawn(processes, "ls", ["-la"])

# Send signal to process
:ok = Raxol.Terminal.Processes.signal(processes, pid, :sigterm)

# Wait for process completion
{:ok, status} = Raxol.Terminal.Processes.wait(processes, pid)
```

## Configuration

The process manager can be configured with the following options:

```elixir
config = %{
  shell: "/bin/bash",
  env: %{
    "TERM" => "xterm-256color",
    "LANG" => "en_US.UTF-8"
  },
  cwd: "/home/user",
  process_limit: 100,
  default_priority: 0
}

processes = Raxol.Terminal.Processes.new(config)
```

## Implementation Details

### Process Types

1. **Shell Processes**

   - Interactive shells
   - Command execution
   - Shell integration
   - Shell history

2. **Background Processes**

   - Daemon processes
   - Job control
   - Process groups
   - Session management

3. **Special Processes**
   - PTY master/slave
   - Signal handlers
   - Zombie reaping
   - Init process

### Process Management

1. **Lifecycle Management**

   - Process creation
   - Process monitoring
   - Process termination
   - Exit status handling

2. **Resource Management**
   - CPU scheduling
   - Memory limits
   - File descriptors
   - Process priorities

### Process State

1. **Process Information**

   - Process ID
   - Parent process
   - Process group
   - Session ID

2. **Resource Usage**
   - CPU usage
   - Memory usage
   - Open files
   - Network connections

## API Reference

### Process Management

```elixir
# Initialize process manager
@spec new() :: t()

# Spawn new process
@spec spawn(processes :: t(), command :: String.t(), args :: [String.t()]) :: {:ok, pid()} | {:error, String.t()}

# Terminate process
@spec terminate(processes :: t(), pid :: pid()) :: :ok | {:error, String.t()}

# Wait for process
@spec wait(processes :: t(), pid :: pid()) :: {:ok, integer()} | {:error, String.t()}
```

### Process Control

```elixir
# Send signal to process
@spec signal(processes :: t(), pid :: pid(), signal :: atom()) :: :ok | {:error, String.t()}

# Set process priority
@spec set_priority(processes :: t(), pid :: pid(), priority :: integer()) :: :ok | {:error, String.t()}

# Get process info
@spec get_info(processes :: t(), pid :: pid()) :: {:ok, map()} | {:error, String.t()}
```

### Environment Management

```elixir
# Set environment variable
@spec set_env(processes :: t(), key :: String.t(), value :: String.t()) :: t()

# Get environment variable
@spec get_env(processes :: t(), key :: String.t()) :: {:ok, String.t()} | :error

# Set working directory
@spec set_cwd(processes :: t(), path :: String.t()) :: :ok | {:error, String.t()}
```

## Events

The process management component emits the following events:

- `:process_spawned` - When a new process is created
- `:process_exited` - When a process terminates
- `:process_signaled` - When a signal is sent to a process
- `:process_error` - When a process encounters an error
- `:env_changed` - When environment variables change
- `:cwd_changed` - When working directory changes

## Example

```elixir
defmodule MyTerminal do
  alias Raxol.Terminal.Processes

  def example do
    # Create a new process manager
    processes = Processes.new()

    # Configure environment
    processes = processes
      |> Processes.set_env("TERM", "xterm-256color")
      |> Processes.set_env("PATH", "/usr/local/bin:/usr/bin")

    # Start a shell process
    {:ok, shell_pid} = Processes.spawn(processes, "/bin/bash", [])

    # Start a background process
    {:ok, bg_pid} = Processes.spawn(processes, "long-running-task", [])

    # Monitor process state
    {:ok, info} = Processes.get_info(processes, bg_pid)
    IO.inspect(info.status)

    # Send signal to process
    :ok = Processes.signal(processes, bg_pid, :sigterm)

    # Wait for process to exit
    {:ok, status} = Processes.wait(processes, bg_pid)
  end
end
```

## Testing

The process management component includes comprehensive tests:

```elixir
defmodule Raxol.Terminal.ProcessesTest do
  use ExUnit.Case
  alias Raxol.Terminal.Processes

  test "spawns processes correctly" do
    processes = Processes.new()
    {:ok, pid} = Processes.spawn(processes, "echo", ["test"])
    {:ok, status} = Processes.wait(processes, pid)
    assert status == 0
  end

  test "handles signals correctly" do
    processes = Processes.new()
    {:ok, pid} = Processes.spawn(processes, "sleep", ["10"])
    :ok = Processes.signal(processes, pid, :sigterm)
    {:ok, status} = Processes.wait(processes, pid)
    assert status != 0
  end

  test "manages environment variables" do
    processes = Processes.new()
    processes = Processes.set_env(processes, "TEST", "value")
    assert {:ok, "value"} = Processes.get_env(processes, "TEST")
  end

  test "handles working directory changes" do
    processes = Processes.new()
    :ok = Processes.set_cwd(processes, "/tmp")
    {:ok, cwd} = Processes.get_cwd(processes)
    assert cwd == "/tmp"
  end
end
```