Support output field for inference server

serve/main.py

@@ -22,7 +22,7 @@ if topology_filepath is None:
     )
 
 with_gpu = os.getenv('WITH_GPU', '0') != '0'
-
+output_field = os.getenv('OUTPUT_FIELD', 'value')
 port = int(os.getenv('PORT', '80'))
 
 app = Flask(__name__)
@@ -55,6 +55,9 @@ def infer():
 # threads, so we create a single worker thread.
 def worker():
     paddle.init(use_gpu=with_gpu)
+
+    fields = filter(lambda x: len(x) != 0, output_field.split(","))
+
     with open(tarfn) as param_f, open(topology_filepath) as topo_f:
         params = paddle.parameters.Parameters.from_tar(param_f)
         inferer = paddle.inference.Inference(parameters=params, fileobj=topo_f)
@@ -67,7 +70,7 @@ def worker():
             for i, key in enumerate(j):
                 d.append(j[key])
                 feeding[key] = i
-                r = inferer.infer([d], feeding=feeding)
+                r = inferer.infer([d], feeding=feeding, field=fields)
         except:
             trace = traceback.format_exc()
             recvQ.put((False, trace))