Merge 071ad19 into 10a50f6

README.md

@@ -36,8 +36,10 @@ $ swim-protocol-demo -c --name 127.0.0.1:2003 --peer 127.0.0.1:2001 --metadata n
 $ swim-protocol-demo -c --name 127.0.0.1:2004 --peer 127.0.0.1:2003 --metadata name four
 ```
 
-Every 10 seconds or so, each member will randomize its `token` metadata field,
-which should be disseminated across the cluster with [eventual consistency][6].
+Typing in any window will disseminate what has been typed across the cluster
+with [eventual consistency][6].
+
+![swim-protocol-demo](https://user-images.githubusercontent.com/438413/117894784-16580e80-b28b-11eb-9903-762fff92eaf7.gif)
 
 ### Getting Started
 

docs/intro.rst

@@ -129,9 +129,9 @@ Glossary
       :term:`gossip` is new enough to be applied or disseminated.
 
    demo
-      The included `demo`_ is designed to randomize metadata changes on an
-      interval to see them disseminated across the cluster, as well as watch as
-      :term:`member` statuses change as demo instances are stopped and started.
+      The included `demo`_ is designed to show typing being disseminated across
+      the cluster, as well as watch as :term:`member` statuses change as demo
+      instances are stopped and started.
 
 .. _SWIM: https://www.cs.cornell.edu/projects/Quicksilver/public_pdfs/SWIM.pdf
 .. _Serf: https://www.serf.io/docs/internals/gossip.html

setup.py

@@ -28,7 +28,7 @@
     license = f.read()
 
 setup(name='swim-protocol',
-      version='0.3.6',
+      version='0.3.7',
       author='Ian Good',
       author_email='ian@icgood.net',
       description='SWIM protocol implementation for exchanging cluster '

swimprotocol/demo/__init__.py

@@ -34,8 +34,7 @@ def main() -> int:
     group.add_argument('-c', '--curses', action='store_true',
                        help='Enable the curses display.')
     group.add_argument('-i', '--token-interval', metavar='SECONDS',
-                       type=float, default=10.0,
-                       help='Cluster member token update interval.')
+                       type=float, help='Randomize metadata on an interval.')
 
     args = parser.parse_args()
 

swimprotocol/demo/changes.py

@@ -5,7 +5,7 @@
 import random
 import uuid
 from contextlib import AsyncExitStack
-from typing import NoReturn
+from typing import Optional, NoReturn
 
 from ..members import Members
 
@@ -23,8 +23,10 @@ async def _randomize_local(members: Members, interval: float) -> NoReturn:
         await asyncio.sleep(sleep_sec)
 
 
-def change_metadata(members: Members, interval: float) -> AsyncExitStack:
+def change_metadata(members: Members, interval: Optional[float]) \
+        -> AsyncExitStack:
     exit_stack = AsyncExitStack()
-    task = asyncio.create_task(_randomize_local(members, interval))
-    exit_stack.callback(task.cancel)
+    if interval is not None:
+        task = asyncio.create_task(_randomize_local(members, interval))
+        exit_stack.callback(task.cancel)
     return exit_stack

swimprotocol/demo/screen.py

@@ -3,6 +3,7 @@
 
 import asyncio
 import curses
+import string
 from contextlib import AsyncExitStack
 from curses import wrapper
 from threading import Event, Condition
@@ -14,6 +15,12 @@
 __all__ = ['run_screen']
 
 
+def _is_printable(ch: int) -> bool:
+    return ch >= 0 and ch < 256 \
+            and ch in string.printable.encode('ascii') \
+            and ch not in set(b'\t\r\n\x0b\x0c')
+
+
 class Screen:
 
     def __init__(self, members: Members) -> None:
@@ -71,6 +78,11 @@ def _render(self, stdscr: Any) -> None:
         available = len(self.members.get_status(Status.AVAILABLE)) + 1
         stdscr.addstr(f'{available}', curses.A_BOLD)
 
+    def _set_typed(self, typed: bytes) -> None:
+        members = self.members
+        new_metadata = dict(members.local.metadata) | {'typed': typed}
+        members.update(members.local, new_metadata=new_metadata)
+
     def main(self, stdscr: Any) -> None:
         curses.cbreak()
         curses.use_default_colors()
@@ -84,12 +96,21 @@ def main(self, stdscr: Any) -> None:
         curses.init_pair(8, curses.COLOR_RED, -1)
         curses.curs_set(0)
         stdscr.clear()
+        stdscr.timeout(0)
+        typed = b''
         while not self.done.is_set():
             stdscr.clear()
             self._render(stdscr)
             stdscr.refresh()
-            with self.ready:
-                self.ready.wait(timeout=1.0)
+            for i in range(20):
+                with self.ready:
+                    if self.ready.wait(timeout=0.05):
+                        break
+                ch = stdscr.getch()
+                if _is_printable(ch):
+                    typed += bytes([ch])
+                    typed = typed[-30:]
+                    self._set_typed(typed)
 
     async def run_thread(self) -> None:
         await asyncio.to_thread(wrapper, self.main)

swimprotocol/members.py

@@ -105,7 +105,8 @@ def _set_status(self, status: Status) -> None:
     def _set_metadata(self, metadata: Mapping[str, bytes]) -> None:
         assert self._pending_metadata is None
         pending_metadata = frozenset(metadata.items())
-        if pending_metadata != self._metadata:
+        if self._metadata_dict is self.METADATA_UNKNOWN or \
+                pending_metadata != self._metadata:
             self._pending_metadata = pending_metadata
 
     def _save(self, source: Optional[Member], next_clock: int) -> bool: