feat(imagegeneration): updated image schema and inference params

lambda/aws-contentgen-appsync-lambda/src/image_generator.py

@@ -108,24 +108,48 @@ def image_moderation(self):
 
     def generate_image(self,input_params):
 
-        """Generate image using Using bedrock with configured modelid"""
+        """Generate image using Using bedrock with configured modelid and params"""
 
         input_text=self.input_text
-        model_id=input_params['model_config']['modelId']
-        cfg_scale=input_params['model_config']['model_kwargs']['cfg_scale'] 
-        seed=input_params['model_config']['model_kwargs']['seed']
-        steps=input_params['model_config']['model_kwargs']['steps']
-
-        promptTemplate="{\"text_prompts\":[{\"text\":\"$input_text\\n\"}],\"cfg_scale\":$cfg_scale,\"seed\":$seed,\"steps\":$steps}"
-
-        prompt=promptTemplate.replace("$input_text", input_text).replace("$cfg_scale", str(cfg_scale)).replace("$seed", str(seed)).replace("$steps", str(steps))
 
+        # add default negative prompts
+        if 'negative_prompts' in input_params:
+               sample_string_bytes = base64.b64decode(input_params['negative_prompts'])
+               decoded_negative_prompts = sample_string_bytes.decode("utf-8")
+               logger.info(f"decoded negative prompts are :: {decoded_negative_prompts}")
+               negative_prompts= decoded_negative_prompts
+        else:
+              negative_prompts= ["poorly rendered","poor background details"]
+
+        model_id=input_params['model_config']['modelId']
+
+        model_kwargs=input_params['model_config']['model_kwargs']
+        params= get_inference_parameters(model_kwargs)
+
+        logger.info(f'SD params :: {params}')
+
+
+        request = json.dumps({
+                "text_prompts": (
+                        [{"text": input_text, "weight": 1.0}]
+                        + [{"text": negprompt, "weight": -1.0} for negprompt in negative_prompts]
+                ),
+                "cfg_scale":params['cfg_scale'],
+                "seed": params['seed'],
+                "steps": params['steps'],
+                "style_preset": params['style_preset'],
+                "clip_guidance_preset": params['clip_guidance_preset'],
+                "sampler": params['sampler'],
+                "width": params['width'],
+                "height": params['height']
+                })
+
         try:
             return  self.bedrock_client.invoke_model(
                 modelId= model_id,
                 contentType= "application/json",
                 accept= "application/json",
-                body=prompt
+                body=request
                 )
         except Exception as e:
             logger.error(f"Error occured during generating image:: {e}")
@@ -172,4 +196,50 @@ def send_job_status(self,variables):
             auth=aws_auth_appsync,
             timeout=10
         )
-        logger.info('res :: {}',responseJobstatus)
+        logger.info('res :: {}',responseJobstatus)
+
+
+def get_inference_parameters(model_kwargs):
+      """ Read inference parameters and set default values"""
+      if 'seed' in model_kwargs:
+              seed= model_kwargs['seed']
+      else:
+              seed=452345
+      if 'cfg_scale' in model_kwargs:
+              cfg_scale= model_kwargs['cfg_scale']
+      else:
+              cfg_scale=10
+      if 'steps' in model_kwargs:
+              steps= model_kwargs['steps']
+      else:
+              steps=10
+      if 'style_preset' in model_kwargs:
+              style_preset= model_kwargs['style_preset']
+      else:
+              style_preset='photographic'
+      if 'clip_guidance_preset' in model_kwargs:
+              clip_guidance_preset= model_kwargs['clip_guidance_preset']
+      else:
+              clip_guidance_preset='FAST_GREEN'
+      if 'width' in model_kwargs:
+              width= model_kwargs['width']
+      else:
+              width=512
+      if 'height' in model_kwargs:
+              height= model_kwargs['height']
+      else:
+              height=512
+      if 'sampler' in model_kwargs:
+              sampler= model_kwargs['sampler']
+      else:
+              sampler='K_DPMPP_2S_ANCESTRAL'
+      return {
+            "cfg_scale": cfg_scale,
+            "seed": seed,
+            "steps": steps,
+            "style_preset": style_preset,
+            "clip_guidance_preset": clip_guidance_preset,
+            "sampler": sampler,
+            "width": width,
+            "height": height,
+      }

resources/gen-ai/aws-contentgen-appsync-lambda/schema.graphql

@@ -11,6 +11,7 @@ input ImageInput {
 	filename: String
 	model_config: ModelConfiguration
 	input_text: String!
+	negative_prompts: String
 }
 
 type ImageOutput @aws_iam @aws_cognito_user_pools {