[Community Pipelines]

Community Pipelines

As of diffusers==0.4.0, you can make use of Community Pipelines.

The goal with community pipelines is to have a community-driven offering of an exotic variety of features built on top of diffusers which is maintained by the community

How to use community pipelines

Load community pipelines passing the custom_pipeline argument to DiffusionPipeline, as one of the files in diffusers/examples/community.

pipe = DiffusionPipeline.from_pretrained("CompVis/stable-diffusion-v1-4", custom_pipeline="filename_in_the_community_folder")

Contribute to the community pipelines by sending a PR with your own pipelines to diffusers/examples/community, we will merge them quickly.

Why community pipelines?

While the code of community pipelines will not be in official PyPI releases, the code is usable from the diffusers package >= 0.4.0. The reason community pipelines are not under the officially maintained pipelines but instead under the examples/community folder is:

• There is a vast amount of use cases that could be supported, but it’s hard to figure out what’s important enough to be maintained rigorously.
• Different opinions on the design philosophy of pipelines.
• We don’t want to block the community from adding features they would like to add, but at the same time, we cannot take the burden of full maintenance upon ourselves.

So by providing community pipelines, we allow community members to contribute and share their work while having flexibility and development speed while making their work easily accessible to the rest of the ecosystem.

What pipelines to contribute?

Feel free to contribute with any pipeline that is exciting to you! If you want some ideas, we’ve compiled some ideas in different issues here, but you can do other pipelines as well! Some examples:

1. 1. https://github.com/huggingface/diffusers/issues/873
2. 2. https://github.com/huggingface/diffusers/issues/875
3. 3. https://github.com/huggingface/diffusers/issues/876
4. 4. https://github.com/huggingface/diffusers/issues/877
5. 5. https://github.com/huggingface/diffusers/issues/871
6. 6. https://github.com/huggingface/diffusers/issues/872

How to contribute to a community pipeline?

Let’s make an example! Say you want to define a pipeline that just does a single forward pass to a U-Net and then calls a scheduler only once (Note, this doesn’t make any sense from a scientific point of view, but only represents an example of how things work under the hood).

Cool! So you open your favorite IDE and start creating your pipeline 💻. First, what model weights and configurations do we need? We have a U-Net and a scheduler, so our pipeline should take a U-Net and a scheduler as an argument. Also, as stated above, you’d like to be able to load weights and the scheduler config for Hub and share your code with others, so we’ll inherit from DiffusionPipeline:

from diffusers import DiffusionPipeline
import torch

class UnetSchedulerOneForwardPipeline(DiffusionPipeline):

    def __init__(self, unet, scheduler):
       super().__init__()

Now, we must save the unet and scheduler in a config file so that you can save your pipeline with save_pretrained. Therefore, make sure you add every component that is save-able to the register_modules function:

from diffusers import DiffusionPipeline
import torch

class UnetSchedulerOneForwardPipeline(DiffusionPipeline):

    def __init__(self, unet, scheduler):
       super().__init__()

       self.register_modules(unet=unet, scheduler=scheduler)

Cool, the init is done! 🔥 Now, let’s go into the forward pass, which we recommend defining as __call__ . Here you’re given all the creative freedom there is. For our amazing “one-step” pipeline, we simply create a random image and call the unet once and the scheduler once:

from diffusers import DiffusionPipeline
import torch

class UnetSchedulerOneForwardPipeline(DiffusionPipeline):

    def __init__(self, unet, scheduler):
        super().__init__()

        self.register_modules(unet=unet, scheduler=scheduler)

    def __call__(self):
          image = torch.randn(
              (1, self.unet.in_channels, self.unet.sample_size, self.unet.sample_size),
          )
          timestep = 1

          model_output = self.unet(image, timestep).sample
          scheduler_output = self.scheduler.step(model_output, timestep, image).prev_sample

          return scheduler_output

Cool, that’s it! 🚀 You can now run this pipeline by passing a unet and a scheduler to the init:

from diffusers import DDPMScheduler, Unet2DModel

scheduler = DDPMScheduler()
unet = UNet2DModel()

pipeline = UnetSchedulerOneForwardPipeline(unet=unet, scheduler=scheduler)

output = pipeline()

But what’s even better is that you can load pre-existing weights into the pipeline if they match exactly your pipeline structure. This is e.g. the case for https://huggingface.co/google/ddpm-cifar10-32 so that we can do the following:

pipeline = UnetSchedulerOneForwardPipeline.from_pretrained("google/ddpm-cifar10-32")

output = pipeline()

We want to share this amazing pipeline with the community, so we would open a PR request to add the following code under one_step_unet.py to https://github.com/huggingface/diffusers/tree/main/examples/community .

from diffusers import DiffusionPipeline
import torch

class UnetSchedulerOneForwardPipeline(DiffusionPipeline):

    def __init__(self, unet, scheduler):
        super().__init__()

        self.register_modules(unet=unet, scheduler=scheduler)

    def __call__(self):
          image = torch.randn(
              (1, self.unet.in_channels, self.unet.sample_size, self.unet.sample_size),
          )
          timestep = 1

          model_output = self.unet(image, timestep).sample
          scheduler_output = self.scheduler.step(model_output, timestep, image).prev_sample

          return scheduler_output

Our amazing pipeline got merged here: https://github.com/huggingface/diffusers/pull/840. Now everybody that has diffusers >= 0.4.0 installed can use our pipeline magically 🪄 as follows:

from diffusers import DiffusionPipeline

pipe = DiffusionPipeline.from_pretrained("google/ddpm-cifar10-32", custom_pipeline="one_step_unet")
pipe()

Another way to upload your custom_pipeline, besides sending a PR, is uploading the code that contains it to the Hugging Face Hub, as exemplified here.

Try it out now - it works!

In general, you will want to create much more sophisticated pipelines, so we recommend looking at existing pipelines here: https://github.com/huggingface/diffusers/tree/main/examples/community

IMPORTANT: You can use whatever package you want in your community pipeline file - as long as the user has it installed, everything will work fine. Make sure you have one and only one pipeline class that inherits from DiffusionPipeline as this will be automatically detected.

How do community pipelines work?

A community pipeline is a class that has to inherit from DiffusionPipeline: https://huggingface.co/docs/diffusers/api/diffusion_pipeline#diffusers.DiffusionPipeline and that has been added to https://github.com/huggingface/diffusers/tree/main/examples/community. The community can load the pipeline code via the custom_pipeline argument from DiffusionPipeline. See docs here: https://huggingface.co/docs/diffusers/api/diffusion_pipeline#diffusers.DiffusionPipelinehttps://huggingface.co/docs/diffusers/api/diffusion_pipeline#diffusers.DiffusionPipeline.from_pretrained.custom_pipeline

This means:

• The model weights and configs of the pipeline should be loaded from the pretrained_model_name_or_path argument: https://huggingface.co/docs/diffusers/api/diffusion_pipeline#diffusers.DiffusionPipeline.from_pretrained.pretrained_model_name_or_path whereas the code that powers the community pipeline is defined in a file added in https://github.com/huggingface/diffusers/tree/main/examples/community

Now, it might very well be that only some of your pipeline components weights can be downloaded from an official repo. The other components should then be passed directly to init as is the case for the ClIP guidance notebook here)

The magic behind all of this is that we load the code directly from GitHub. You can check it out in more detail if you follow the functionality defined here: https://github.com/huggingface/diffusers/blob/d3eb3b35bec35f3f4e56b7528577714bf489d464/src/diffusers/pipeline_utils.py#L405 . This is why a community pipeline merged to GitHub will be directly available to all diffusers packages.

[WASasquatch]

Looking at all these pipelines. Things are quickly falling apart, imo. Pipelines doing one little thing, and then its own pipeline to manage, is horribly counter-productive. This is falling back to the fundamental issue with diffusers itself, and needing manage tons of pipes in code just to take on certain tasks (like img2img, inpainting), and now what about, clip guided diffusion (still limited to just text2img), or wildcard pipeline being worked on just for wildcards and again, based on limited DiffusionPipeline.

The idea behind community pipelines does not seem flushed. If this was a modular plugin idea, where a pipeline could have plugins that add functionality, it would to make far more sense.

None of this seems to think of the end developers/users and how this is implemented in an efficient, and minimal API philosophy. Give it a couple months, and in order to use all the cool things community pipelines has to offer, you’ll have a script 10x the size it needs to be just to implement all these pipes, put in the logic to use the right pipes for the right tasks, etc, etc, essentially building your own API, off an API, to do something…

Like you released the mega community pipeline, which is still kinda useless. It’s just a community pipeline which conveniently has img2img and inpainting, but is incompatible with the features one may want, like CLIP Guided Diffusion not being limited to just text2img because it is its own pipe. So what is the point in Mega if it’s not useful for any of this?

[teticio]

@teticio could you open a first draft PR maybe to show the design? I’m not 100% sure exactly how the inheritance problem looks like at the moment.

Hi @patrickvonplaten, the PR is ready to go here https://github.com/huggingface/diffusers/pull/1334, for when you have a chance to look at it.