Adds Range header support to content app

This unskips the `Range` header and adds support for it to the content
app.

closes #8865

CHANGES/8865.bugfix

@@ -0,0 +1,2 @@
+Fixed bug where content app would not respond to `Range` HTTP Header in requests, e.g. from Anaconda
+clients.

pulpcore/content/handler.py

@@ -436,6 +436,8 @@ async def _match_and_stream(self, path, request):
             :class:`aiohttp.web.StreamResponse` or :class:`aiohttp.web.FileResponse`: The response
                 streamed back to the client.
         """
+        # import pydevd_pycharm
+        # pydevd_pycharm.settrace('localhost', port=29437, stdoutToServer=True, stderrToServer=True)
 
         def match_distribution_blocking():
             return self._match_distribution(path)
@@ -665,7 +667,7 @@ def get_remote_artifacts_blocking():
                 return response
 
             except (ClientResponseError, UnsupportedDigestValidationError) as e:
-                log.warn(
+                log.warning(
                     _("Could not download remote artifact at '{}': {}").format(
                         remote_artifact.url, str(e)
                     )
@@ -809,15 +811,33 @@ def cast_remote_blocking():
 
         remote = await loop.run_in_executor(None, cast_remote_blocking)
 
-        async def handle_headers(headers):
+        rng = request.http_range
+
+        async def handle_response_headers(headers):
             for name, value in headers.items():
                 if name.lower() in self.hop_by_hop_headers:
                     continue
                 response.headers[name] = value
             await response.prepare(request)
 
         async def handle_data(data):
-            await response.write(data)
+            if rng.start or rng.stop:
+                start_byte_pos = 0
+                end_byte_pos = len(data)
+                if rng.start:
+                    start_byte_pos = max(0, rng.start - downloader._size)
+                if rng.stop:
+                    end_byte_pos = min(len(data), rng.stop - downloader._size)
+
+                if start_byte_pos < 0:
+                    raise Exception("start is less than zerooooo")
+                if end_byte_pos > len(data):
+                    raise Exception("end is more than len(data)")
+
+                data_for_client = data[start_byte_pos:end_byte_pos]
+                await response.write(data_for_client)
+            else:
+                await response.write(data)
             if remote.policy != Remote.STREAMED:
                 await original_handle_data(data)
 
@@ -826,7 +846,7 @@ async def finalize():
                 await original_finalize()
 
         downloader = remote.get_downloader(
-            remote_artifact=remote_artifact, headers_ready_callback=handle_headers
+            remote_artifact=remote_artifact, headers_ready_callback=handle_response_headers
         )
         original_handle_data = downloader.handle_data
         downloader.handle_data = handle_data

pulpcore/download/http.py

@@ -207,7 +207,8 @@ async def _handle_response(self, response):
         if self.headers_ready_callback:
             await self.headers_ready_callback(response.headers)
         while True:
-            chunk = await response.content.read(1048576)  # 1 megabyte
+            # chunk = await response.content.read(1048576)  # 1 megabyte
+            chunk = await response.content.read(3)  # 3 bytes
             if not chunk:
                 await self.finalize()
                 break  # the download is done

pulpcore/tests/functional/api/using_plugin/test_distributions.py

@@ -329,7 +329,6 @@ def test_content_served_immediate(self):
         self.setup_download_test("immediate")
         self.do_test_content_served()
 
-    @unittest.skip("https://pulp.plan.io/issues/8865")
     def test_content_served_on_demand_with_range_request(self):
         """Assert that on_demand content can be properly downloaded with range requests."""
         self.setup_download_test("on_demand")
@@ -389,9 +388,11 @@ def do_test_content_served(self):
         self.assertEqual(len(pulp_manifest), FILE_FIXTURE_COUNT, pulp_manifest)
 
     def do_range_request_download_test(self):
+        # import pydevd_pycharm
+        # pydevd_pycharm.settrace('localhost', port=29437, stdoutToServer=True, stderrToServer=True)
         file_path = "1.iso"
 
-        headers = {"Range": "bytes=0-9"}  # first 10 bytes
+        headers = {"Range": "bytes=2-11"}  # first 10 bytes
         NUM_BYTES = 10
 
         req1 = download_content_unit(