darth-veitcher-comfydv/docs/index.md

comfydv

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

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 without crashing the server. Wire the status toggle to a boolean condition to skip the rest of the queue when a condition isn't met.

Install

Via ComfyUI Manager (recommended): search for comfydv and click Install.

Manual:

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

Restart ComfyUI. The nodes appear under the dv/ category in the node menu. The only runtime dependency is jinja2, installed automatically via requirements.txt.

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Format String

Formats text from a Python f-string or Jinja2 template. As you type the template, input sockets appear and disappear automatically — one per variable detected.

Python f-strings

Type {variable_name} and a socket appears. Wire it to any string output in your workflow.

Output	Content
formatted_string	The rendered result
saved_file_path	Path written to disk (if save_path is set)
<var> …	Pass-through of each input value, for easy chaining

Jinja2 templates

Switch template_type to Jinja2 to unlock filters (| upper, | int, …), conditionals ({% if %}…{% endif %}), and loops.

Variables detected in {{ }} expressions become input sockets exactly as in Simple mode. See the Jinja2 documentation for the full filter/test reference.

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Random Choice

Connect any number of inputs of the same type. Each run picks one at random. Set seed for reproducibility.

• Accepts any ComfyUI type (STRING, IMAGE, CONDITIONING, …)
• Add as many inputs as you like; unused slots are removed automatically when disconnected
• seed = 0 randomises on every run; any other value locks the selection

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Circuit Breaker

Stops the queue gracefully when a condition isn't met — no crash, no error, just a clean halt.

Wire an image (or any trigger) into trigger and a boolean into status. When status is false the node raises InterruptProcessingException, which tells ComfyUI to stop the current run cleanly. When status is true the image passes through unchanged.

Typical use: skip an expensive upscale step when a quality-check node says the draft is already good enough.