Update pytorch/sentiment-analysis example (#1064)

Author: deliahu

examples/pytorch/sentiment-analyzer/cortex.yaml

@@ -4,7 +4,6 @@
   predictor:
     type: python
     path: predictor.py
-    config:
-      model: s3://cortex-examples/pytorch/sentiment-analyzer/export.pkl
   compute:
     cpu: 1
+    # gpu: 1  # This is optional, since the API will run on CPUs (albeit slower)

examples/pytorch/sentiment-analyzer/fastai_sentiment_ulmfit.ipynb

@@ -1,23 +1,15 @@
 # WARNING: you are on the master branch, please refer to the examples on the branch that matches your `cortex version`
 
-import os
-import re
-import boto3
-from botocore import UNSIGNED
-from botocore.client import Config
-from fastai.text import load_learner
+import torch
+from transformers import pipeline
 
 
 class PythonPredictor:
     def __init__(self, config):
-        # download the model
-        bucket, key = re.match("s3://(.+?)/(.+)", config["model"]).groups()
-        s3 = boto3.client("s3", config=Config(signature_version=UNSIGNED))
-        os.mkdir("/tmp/model")
-        s3.download_file(bucket, key, "/tmp/model/export.pkl")
+        device = 0 if torch.cuda.is_available() else -1
+        print(f"using device: {'cuda' if device == 0 else 'cpu'}")
 
-        self.predictor = load_learner("/tmp/model")
+        self.analyzer = pipeline(task="sentiment-analysis", device=device)
 
     def predict(self, payload):
-        prediction = self.predictor.predict(payload["text"])
-        return prediction[0].obj
+        return self.analyzer(payload["text"])[0]

examples/pytorch/sentiment-analyzer/predictor.py

@@ -1,2 +1,2 @@
-fastai==1.0.60
-torch==1.3.1
+torch
+transformers