From 373c38113f0e607b8be6cf58e59f86f718118db0 Mon Sep 17 00:00:00 2001
From: Matthias Bisping <matthias.bisping@iqser.com>
Date: Thu, 5 May 2022 16:26:18 +0200
Subject: [PATCH] refactoring

---
 pyinfra/server/dispatcher/dispatcher.py |  2 +-
 pyinfra/server/server.py                | 41 +++++++++++++------------
 2 files changed, 23 insertions(+), 20 deletions(-)

diff --git a/pyinfra/server/dispatcher/dispatcher.py b/pyinfra/server/dispatcher/dispatcher.py
index 8d60ce8..3f71804 100644
--- a/pyinfra/server/dispatcher/dispatcher.py
+++ b/pyinfra/server/dispatcher/dispatcher.py
@@ -9,7 +9,7 @@ class Nothing:
 
 
 def has_next(peekable_iter):
-    return peekable_iter.peek(Nothing) != Nothing
+    return peekable_iter.peek(Nothing) is not Nothing
 
 
 class Dispatcher:
diff --git a/pyinfra/server/server.py b/pyinfra/server/server.py
index f9feb94..d88c2dd 100644
--- a/pyinfra/server/server.py
+++ b/pyinfra/server/server.py
@@ -8,6 +8,7 @@ from typing import Iterable
 from flask import Flask, jsonify, request
 from funcy import compose
 
+from pyinfra.server.dispatcher.dispatcher import Nothing
 from pyinfra.server.utils import unpack_batchop_pack, unpack_op_pack
 from pyinfra.utils.buffer import bufferize
 from pyinfra.utils.func import starlift, llift
@@ -23,22 +24,28 @@ def make_processor_fn(operation, buffer_size, batched):
     wrapper = unpack_batchop_pack if batched else compose(llift, unpack_op_pack)
     operation = wrapper(operation)
 
-    return bufferize(operation, buffer_size=buffer_size, persist_fn=attrgetter("json"))
+    return bufferize(operation, buffer_size=buffer_size)
 
 
 class Processor(abc.ABC):
     def __init__(self, processor_fn):
-        self.results = []
+        self.execution_queue = []
         self.processor_fn = processor_fn
 
-    def lazy(self, package, final):
-        self.results = chain(self.results, self.processor_fn(package, final=final))
-
-    def eager(self, package, final):
+    def run(self, package, final):
+        """Eagerly execute processor function and return result immediately."""
         return self.processor_fn(package, final=final)
 
-    def yield_result(self):
-        return next(self.results)
+    def submit(self, package, final):
+        """Submit computation request to execution queue; computation is performed on demand."""
+        self.execution_queue = chain(self.execution_queue, [lambda: self.processor_fn(package, final=final)])
+
+    def compute_next(self):
+        """Processes the next request."""
+        try:
+            return next(self.execution_queue)()
+        except StopIteration:
+            return Nothing
 
 
 def set_up_processing_server(process_fn):
@@ -53,28 +60,24 @@ def set_up_processing_server(process_fn):
 
     @app.route("/process", methods=["POST", "PATCH"])
     def process():
-        response_payload = processor.eager(request, final=request.method == "POST")
+        response_payload = processor.run(request.json, final=request.method == "POST")
         return jsonify(response_payload)
 
     @app.route("/submit", methods=["POST", "PATCH"])
     def submit():
-        processor.lazy(request, final=request.method == "POST")
+        processor.submit(request.json, final=request.method == "POST")
         return jsonify(f"{request.base_url.replace('/submit', '')}/pickup")
 
     @app.route("/pickup", methods=["GET"])
     def pickup():
-
-        try:
-            resp = jsonify(processor.yield_result())
-            resp.status_code = 206
-
-        except StopIteration:
+        result = processor.compute_next()
+        if result is Nothing:
             resp = jsonify("No more items left")
             resp.status_code = 204
 
-        except:
-            logger.error(traceback.format_exc())
-            raise
+        else:
+            resp = jsonify(result)
+            resp.status_code = 206
 
         return resp