add Stable Diffusion with Amazon Bedrock Python boto3 article

content/post/2023-12-22-stable-diffusion-with-amazon-bedrock-python-boto3.md

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+---
+author: Thomas Taylor
+categories:
+- cloud
+- programming
+- ai
+date: 2023-12-22T02:00:00-05:00
+description: How to call use the Amazon Bedrock Runtime boto3 SDK to invoke the Stable Diffusion model
+images:
+- images/MGTrlU.png
+tags:
+- aws
+- aws-cdk
+- python
+- serverless
+- generative-ai
+title: Stable Diffusion with Amazon Bedrock Python boto3
+---
+
+![invoking amazon bedrock runtime stable diffusion model](images/MGTrlU.png)
+
+Amazon Bedrock is a managed service provided by AWS that allows users to invoke models. For more information about the service, please refer to their [user guide here][1].
+
+For this article, we're going to focus on how to invoke the Stable Diffusion model using the Python SDK: `boto3`. If you want to learn about the Amazon Bedrock SDK in general or how to invoke Claude with it, I have an [article here][2] that goes into detail.
+
+## What is Stable Diffusion
+
+Stable diffusion is a text-to-image model first released in 2022. The term "diffusion" originates from [diffusion models][3] in machine learning. OpenAI's DALL-E 2 is another example of a model that leverages diffusion. It's open source, free, and easy to run! In addition, it has an active community and a plethora of how-to tutorials.
+
+For more information about Stable Diffusion, check out the [AWS write up][4] about it.
+
+## How use Stable Diffusion with Amazon Bedrock
+
+For this article, we'll be leveraging the Python AWS SDK: `boto3` to call the Stable Diffusion model.
+
+### Install boto3
+
+Let's begin by installing the latest version of `boto3` and the Python image library `PIL`.
+
+```shell
+pip3 install boto3 Pillow
+```
+
+### Lookup the model inference parameters
+
+Each model has specific inference parameters that must be supplied to Bedrock.
+
+As of time of writing, Dec. 22nd 2023, the supported [inference parameters for Stable Diffusion 1.0 text-to-image are][5]:
+
+```text
+{
+    "text_prompts": [
+        {
+            "text": string,
+            "weight": float
+        }
+    ],
+    "height": int,
+    "width": int,
+    "cfg_scale": float,
+    "clip_guidance_preset": string,
+    "sampler": string,
+    "samples",
+    "seed": int,
+    "steps": int,
+    "style_preset": string,
+    "extras": JSON object     
+}
+```
+
+The smallest payload we can send is this:
+
+```text
+{
+    "text_prompts": [{"text": string}]
+}
+```
+
+### Use the invoke_model API
+
+```python
+import base64
+import json
+import io
+from PIL import Image
+
+import boto3
+
+client = boto3.client("bedrock-runtime", region_name="us-east-1")
+
+body = {"text_prompts": [{"text": "A blue bird"}]}
+
+response = client.invoke_model(
+    body=json.dumps(body), modelId="stability.stable-diffusion-xl"
+)
+
+response_body = json.loads(response["body"].read())
+finish_reason = response_body.get("artifacts")[0].get("finishReason")
+
+if finish_reason in ["ERROR", "CONTENT_FILTERED"]:
+    raise Exception(f"Image error: {finish_reason}")
+
+base64_image = response_body["artifacts"][0]["base64"]
+base64_bytes = base64_image.encode("ascii")
+image_bytes = base64.b64decode(base64_bytes)
+image = Image.open(io.BytesIO(image_bytes))
+image.show()
+```
+
+Here is the line-by-line breakdown of the code above:
+- Instantiate the `boto3.client("bedrock-runtime")` client with a `region_name` of `us-east-1`.
+- `json.dumps` a dictionary of Stable Diffusion's required inference parameters
+- Invoke the model by specifying the `body` (string) and `modelId`
+- If the `finishReason` is `ERROR` or `CONTENT_FILTERED`, raise an error
+- Convert the `response_body` to the necessary types for `PIL.Image`
+- Use `image.show()` to display a simple gui with the image
+
+Output:
+
+![stable diffusion output using Amazon Bedrock](images/t1MP6o.png)
+
+
+[1]: https://docs.aws.amazon.com/bedrock/latest/userguide/what-is-bedrock.html
+[2]: https://how.wtf/amazon-bedrock-runtime-examples-using-boto3.html
+[3]: https://en.wikipedia.org/wiki/Diffusion_model
+[4]: https://aws.amazon.com/what-is/stable-diffusion/
+[5]: https://docs.aws.amazon.com/bedrock/latest/userguide/model-parameters-diffusion-1-0-text-image.html