# Ananta (formerly Hydra)

Ananta is a *powerful* command-line tool designed to simplify simultaneous SSH command execution across multiple remote hosts. It enhances workflows, automates repetitive tasks, and improves efficiency for system administrators and developers managing distributed systems.

## Namesake

Ananta draws inspiration from Ananta Shesha or Ananta Nagaraja (อนันตนาคราช), the many-headed serpentine demigod from Hindu mythology deeply rooted in Thai culture.

Initially, this project was named Hydra, referencing the many-headed serpent in Greek mythology. However, due to the abundance of projects named Hydra or hydra-* on PyPI (e.g., the previous project at [https://pypi.org/project/hydra-ssh/](https://pypi.org/project/hydra-ssh/)), it was renamed to Ananta. The commands you now use are `ananta`, which is shorter, more distinctive, and easier to remember than `hydra-ssh`.

## Features

- Concurrent execution of commands across multiple remote hosts
- Flexible host list configuration in **TOML** or **CSV** format
- SSH authentication with public key support
- Lightweight and user-friendly command-line interface
- Color-coded output for easy host differentiation
- Option to separate host outputs for clarity
- Support for cursor control codes for specific layouts (e.g., `fastfetch`, `neofetch`)

## Installation

### System Requirements

- Python 3.10 or higher
- `pip` package manager
- Required dependencies: `asyncssh`, `argparse`, `asyncio`
- Optional: `uvloop` (Unix-based systems) or `winloop` (Windows) for enhanced performance
- For TOML host files on Python 3.10: `tomli` (automatically installed)

### Installing via pip

Install Ananta using pip:

```bash
pip install ananta --user
```

Install Ananta with `uvloop` or `winloop` for *speed* enhancement:

```bash
pip install ananta[speed] --user
```

**Note:** Ensure Python 3.10 or higher is installed. For TOML host files, Python 3.10 requires `tomli`, while Python 3.11 and above use the built-in `tomllib`. If you previously used `hydra-ssh`, update to `pip install ananta` to get the latest version.

## Usage

### Hosts File Format

Ananta supports host files in **TOML** or **CSV** format, allowing flexible configuration of remote hosts. Below are the structures for each format.
***Note:** The TOML format is recommended for its clarity and ease of use. Any hosts file without `.toml` extension will be treated as a CSV file.*

#### TOML Host File

Create a TOML file with a `[default]` section (optional) and host sections. Example:

```toml
[default]
port = 22
username = "user"
key_path = "#"
tags = ["common"]

[host-1]
ip = "10.0.0.1"
port = 2222
key_path = "/home/user/.ssh/id_ed25519"

[host-2]
ip = "10.0.0.2"
tags = ["web"]

[host-3]
ip = "10.0.0.3"
tags = ["arch", "web"]

["host-4"]
ip = "10.0.0.4"
tags = ["ubuntu", "db"]
```

- **[default] Section**:
  - Optional section to set default values for `port`, `username`, `key_path`, and `tags`.
  - `key_path` can be `#` to use the default SSH key which can be specified via `-k` or common keys in `~/.ssh/`.
  - Fields not specified in a host section will use these defaults (except `ip`, which is required).
  - `tags`: Default tags applied to all hosts, appended to host-specific tags.
- **Host Sections**:
  - Each section (e.g., `[host-1]`) defines a host with the following fields to override defaults:
    - `ip`: Required IP address or resolvable hostname
    - `port`: SSH port
    - `username`: SSH username
    - `key_path`: Path to SSH private key
    - `tags`: Optional list of tags (e.g., `["web", "prod"]`)
- **Tags**:
  - Tags from `[default]` are *appended* to tags specified in each host section.
  - For example, if `default.tags = ["common"]` and `host-3.tags = ["arch", "web"]`, `host-2` will have tags `["common", "arch", "web"]`.
  - Use the `-t` option to filter hosts by tags (e.g., `-t common,web` matches hosts with any of these tags).
- **Note**: TOML parsing requires `tomli` on Python 3.10 (included in Ananta's dependencies) or `tomllib` on Python 3.11 and above.

#### CSV Host File

Create a CSV file with the following structure:

```csv
#alias,ip,port,username,key_path,tags(optional - colon separated)
host-1,10.0.0.1,2222,user,/home/user/.ssh/id_ed25519
host-2,10.0.0.2,22,user,#,web
host-3,10.0.0.3,22,user,#,arch:web
host-4,10.0.0.4,22,user,#,ubuntu:db
```

- Lines starting with `#` are ignored.
- **Fields**:
  - `alias`: Unique name for the host
  - `ip`: IP address or resolvable hostname
  - `port`: SSH port number
  - `username`: SSH username
  - `key_path`: Path to SSH private key, or `#` to use the default key (via `-k` or common keys in `~/.ssh/`)
  - `tags`: Optional tags, separated by colons (e.g., `web:db`)
- **Tags**: Used for filtering hosts with the `-t` option (e.g., `-t web,db`).

### Running Commands

Run commands on remote hosts with:

```bash
ananta <options> [hosts file] [command]
```

**Examples:**

```console
# Run 'uptime' on all hosts in a CSV hosts file
$ ananta hosts.csv uptime

# Run 'sensors' with separate output on all hosts in a CSV hosts file
$ ananta -s host.csv sensors

# Run 'fastfetch' with cursor control enabled and separate output on all hosts in a TOML hosts file
$ ananta -cs hosts.toml fastfetch

# Filter hosts by tags 'web' or 'db' (CSV hosts file)
$ ananta -t web,db hosts.csv uptime

# Filter hosts by tags 'common' or 'web' (TOML hosts file, includes default tags)
$ ananta -t common,web hosts.toml uptime

# Update Arch Linux hosts (TOML hosts file)
$ ananta -t arch hosts.toml sudo pacman -Syu --noconfirm
```

### Options

**Single-letter options are case-insensitive.**

- `-n, --no-color`: Disable colorized output
- `-s, --separate-output`: Display output from each host separately
- `-t, --host-tags`: Filter hosts by tag(s), comma-separated (e.g., `web,db`)
- `-w, --terminal-width`: Manually set terminal width
- `-e, --allow-empty-line`: Permit printing of empty lines
- `-c, --allow-cursor-control`: Enable cursor control codes (e.g., for `fastfetch` or `neofetch`)
- `-v, --version`: Display the Ananta version
- `-k, --default-key`: Specify the default SSH private key path

### Demo

[![asciicast](https://asciinema.org/a/711115.svg)](https://asciinema.org/a/711115)

[![asciicast](https://asciinema.org/a/711116.svg)](https://asciinema.org/a/711116)

## License

```text
The MIT License (MIT)

Copyright (c) 2023-2025 cwt(at)bashell(dot)com

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
```

