Add common stuff and week 1 materials

materials/01-intro/anysystem-intro/ping-pong/impl_retry.py

@@ -0,0 +1,52 @@
+from anysystem import Context, Message, Process
+
+
+class PingClient(Process):
+    def __init__(self, proc_id: str, server_id: str):
+        self._id = proc_id
+        self._server_id = server_id
+        self._ping = None
+
+    def on_local_message(self, msg: Message, ctx: Context):
+        # process messages from the local user
+        if msg.type == 'PING':
+            self._ping = msg
+            ctx.send(msg, self._server_id)
+            ctx.set_timer('check_pong', 3)
+
+    def on_start(self, ctx: Context):
+        pass
+
+    def on_message(self, msg: Message, sender: str, ctx: Context):
+        # process messages from the server
+        if msg.type == 'PONG' and self._ping is not None:
+            self._ping = None
+            ctx.cancel_timer('check_pong')
+            ctx.send_local(msg)
+
+    def on_timer(self, timer_name: str, ctx: Context):
+        # process fired timers
+        if timer_name == 'check_pong' and self._ping is not None:
+            ctx.send(self._ping, self._server_id)
+            ctx.set_timer('check_pong', 3)
+
+
+class PingServer(Process):
+    def __init__(self, proc_id: str):
+        self._id = proc_id
+
+    def on_local_message(self, msg: Message, ctx: Context):
+        # process messages from the local user (not used in this example)
+        pass
+
+    def on_start(self, ctx: Context):
+        pass
+
+    def on_message(self, msg: Message, sender: str, ctx: Context):
+        # process messages from the client
+        pong = Message('PONG', {'value': msg['value']})
+        ctx.send(pong, sender)
+
+    def on_timer(self, timer_name: str, ctx: Context):
+        # process fired timers
+        pass