comfydv

A collection of workflow efficiency and quality-of-life nodes built out of necessity for personal ComfyUI use.

What is this?

comfydv fills gaps in ComfyUI's built-in node library: dynamic string formatting, seed-controlled random selection, and graceful workflow interruption. Install it once and connect the nodes like any other — no Python knowledge required.

Node	What it does
Format String	Formats a string from a Python f-string or Jinja2 template. Detects variables in the template and automatically adds/removes input sockets.
Random Choice	Accepts any number of typed inputs and outputs one at random, with a configurable seed for reproducibility.
Circuit Breaker	Halts the current ComfyUI queue run gracefully (raises InterruptProcessingException) without crashing the server.

Install

1. Clone this repo into your ComfyUI custom_nodes/ directory:

   cd /path/to/ComfyUI/custom_nodes
   git clone https://github.com/darth-veitcher/comfydv.git
   

2. Restart ComfyUI. The nodes appear under the dv/ category in the node menu.

Dependencies (jinja2, rich, colorama, termcolor) are listed in pyproject.toml. ComfyUI's Python environment must have them installed — run pip install jinja2 rich colorama termcolor inside that environment if they are missing.

Quickstart

Format String — simple f-string:

1. Add a Format String node to your workflow.
2. Set template_type to Simple and enter Hello {name} in the template field.
3. A name input socket appears automatically — wire it up or type a value.
4. Output 0 (formatted_string) contains Hello <your value>.

Random Choice:

1. Add a Random Choice node.
2. Connect any number of inputs (strings, images, conditioning — any type).
3. Set seed for reproducibility; leave at 0 for a different pick each run.
4. Output is whichever input was selected.

Documentation

Full documentation can be found: darth-veitcher.github.io/comfydv

String Formatting

The FormatString node provides flexible string formatting with dynamic input/output configuration.

Python F-String

A simple python f-string dynamically creates the necessary inputs/outputs for the detected keys.

Jinja 2

Switching to Jinja2 allows you to use more advanced control blocks and other filters/features of that templating language. See Jinja documentation for further details.

Output Structure

The node's outputs are organized for maximum reliability and flexibility:

1. formatted_string (Output 0): The formatted result string - always in position 0
2. saved_file_path (Output 1): Path to saved state file (if save_path provided) - always in position 1
3. Variable outputs (Output 2+): Pass-through values for any variables detected in the template, enabling easy chaining

For example, with template "Hello {name}, you are {age}":

• Output 0: The formatted string (e.g., "Hello Alice, you are 30")
• Output 1: The save file path (or empty string)
• Output 2: The value of name (e.g., "Alice")
• Output 3: The value of age (e.g., "30")

This structure ensures the primary outputs (formatted_string and saved_file_path) are always in predictable, fixed positions for reliable workflow connections.

Random Choice

Ability to take arbitrary length and type of inputs to then output a choice with a controllable seed.