Daggr

daggr

Build visual DAG pipelines connecting Gradio Spaces, HF Inference Providers, and Python functions.

Full docs: https://raw.githubusercontent.com/gradio-app/daggr/refs/heads/main/README.md

Quick Start

from daggr import GradioNode, FnNode, InferenceNode, Graph, ItemList
import gradio as gr

graph = Graph(name="My Workflow", nodes=[node1, node2, ...])
graph.launch()  # Starts web server with visual DAG UI

Node Types

GradioNode - Gradio Spaces

node = GradioNode(
    space_or_url="owner/space-name",
    api_name="/endpoint",
    inputs={
        "param": gr.Textbox(label="Input"),   # UI input
        "other": other_node.output_port,       # Port connection
        "fixed": "constant_value",             # Fixed value
    },
    postprocess=lambda *returns: returns[0],   # Transform response
    outputs={"result": gr.Image(label="Output")},
)

# Example: image generation
img = GradioNode("Tongyi-MAI/Z-Image-Turbo", api_name="/generate",
    inputs={"prompt": gr.Textbox(), "resolution": "1024x1024 ( 1:1 )"},
    postprocess=lambda imgs, *_: imgs[0]["image"],
    outputs={"image": gr.Image()})

Find Spaces with semantic queries (describe what you need): https://huggingface.co/api/spaces/semantic-search?q=generate+music+for+a+video&sdk=gradio&includeNonRunning=false Or by category: https://huggingface.co/api/spaces/semantic-search?category=image-generation&sdk=gradio&includeNonRunning=false (categories: image-generation | video-generation | text-generation | speech-synthesis | music-generation | voice-cloning | image-editing | background-removal | image-upscaling | ocr | style-transfer | image-captioning)

FnNode - Python Functions

def process(input1: str, input2: int) -> str:
    return f"{input1}: {input2}"

node = FnNode(
    fn=process,
    inputs={"input1": gr.Textbox(), "input2": other_node.port},
    outputs={"result": gr.Textbox()},
)

InferenceNode - HF Inference Providers

Find models: https://huggingface.co/api/models?inference_provider=all&pipeline_tag=text-to-image (swap pipeline_tag: text-to-image | image-to-image | image-to-text | image-to-video | text-to-video | text-to-speech | automatic-speech-recognition)

VLM/LLM models: https://router.huggingface.co/v1/models

node = InferenceNode(
    model="org/model:provider",  # model:provider (fal-ai, replicate, together, etc.)
    inputs={"image": other_node.image, "prompt": gr.Textbox()},
    outputs={"image": gr.Image()},
)

Auth: InferenceNode and ZeroGPU Spaces require a HF token. If not in env, ask user to create one: https://huggingface.co/settings/tokens/new?ownUserPermissions=inference.serverless.write&tokenType=fineGrained Out of quota? Pro gives 8x ZeroGPU + 10x inference: https://huggingface.co/subscribe/pro

Port Connections

Pass ports via inputs={...}:

inputs={"param": previous_node.output_port}       # Basic connection
inputs={"item": items_node.items.field_name}      # Scattered (per-item)
inputs={"all": scattered_node.output.all()}       # Gathered (collect list)

ItemList - Dynamic Lists

def gen_items(n: int) -> list:
    return [{"text": f"Item {i}"} for i in range(n)]

items = FnNode(fn=gen_items,
    outputs={"items": ItemList(text=gr.Textbox())})

# Runs once per item
process = FnNode(fn=process_item,
    inputs={"text": items.items.text},
    outputs={"result": gr.Textbox()})

# Collect all results
final = FnNode(fn=combine,
    inputs={"all": process.result.all()},
    outputs={"out": gr.Textbox()})

Checklist

1. Check API before using a Space:

   curl -s "https://<space-subdomain>.hf.space/gradio_api/openapi.json"
   

   Replace <space-subdomain> with the Space's subdomain (e.g., Tongyi-MAI/Z-Image-Turbo → tongyi-mai-z-image-turbo). (Spaces also have "Use via API" link in footer with endpoints and code snippets)

2. Handle files (Gradio returns dicts):

   path = file.get("path") if isinstance(file, dict) else file
   

3. Use postprocess for multi-return APIs:

   postprocess=lambda imgs, seed, num: imgs[0]["image"]
   

4. Debug with .test() to validate a node in isolation:

   node.test(param="value")
   

Common Patterns

# Image Generation
GradioNode("Tongyi-MAI/Z-Image-Turbo", api_name="/generate",
    inputs={"prompt": gr.Textbox(), "resolution": "1024x1024 ( 1:1 )"},
    postprocess=lambda imgs, *_: imgs[0]["image"],
    outputs={"image": gr.Image()})

# Text-to-Speech
GradioNode("Qwen/Qwen3-TTS", api_name="/generate_voice_design",
    inputs={"text": gr.Textbox(), "language": "English", "voice_description": "..."},
    postprocess=lambda audio, status: audio,
    outputs={"audio": gr.Audio()})

# Image-to-Video
GradioNode("alexnasa/ltx-2-TURBO", api_name="/generate_video",
    inputs={"input_image": img.image, "prompt": gr.Textbox(), "duration": 5},
    postprocess=lambda video, seed: video,
    outputs={"video": gr.Video()})

# ffmpeg composition (import tempfile, subprocess)
def combine(video: str|dict, audio: str|dict) -> str:
    v = video.get("path") if isinstance(video, dict) else video
    a = audio.get("path") if isinstance(audio, dict) else audio
    out = tempfile.mktemp(suffix=".mp4")
    subprocess.run(["ffmpeg","-y","-i",v,"-i",a,"-shortest",out])
    return out

Run

uvx --python 3.12 daggr workflow.py &  # Launch in background, hot reloads on file changes

Authentication

Local development: Use hf auth login or set HF_TOKEN env var. This enables ZeroGPU quota tracking, private Spaces access, and gated models.

Deployed Spaces: Users can click "Login" in the UI and paste their HF token. This enables persistence (sheets) so they can save outputs and resume work later. The token is stored in browser localStorage.

When deploying: Pass secrets via --secret HF_TOKEN=xxx if your workflow needs server-side auth (e.g., for gated models in FnNode). Warning: this uses the deployer's token for all users.

Deploy to Hugging Face Spaces

Only deploy if the user has explicitly asked to publish/deploy their workflow.

daggr deploy workflow.py

This extracts the Graph, creates a Space named after it, and uploads everything.

Options:

daggr deploy workflow.py --name my-space      # Custom Space name
daggr deploy workflow.py --org huggingface    # Deploy to an organization
daggr deploy workflow.py --private            # Private Space
daggr deploy workflow.py --hardware t4-small  # GPU (t4-small, t4-medium, a10g-small, etc.)
daggr deploy workflow.py --secret KEY=value   # Add secrets (repeatable)
daggr deploy workflow.py --dry-run            # Preview without deploying