Add ctx.time() as wrapper around ctx.run(time.time) (#121)

Author: slinkydeveloper

examples/random_greeter.py

@@ -9,6 +9,8 @@
 #  https://github.com/restatedev/sdk-typescript/blob/main/LICENSE
 #
 """example.py"""
+from datetime import datetime
+
 # pylint: disable=C0116
 # pylint: disable=W0613
 
@@ -33,7 +35,21 @@ async def greet(ctx: Context, name: str) -> str:
     # As with ctx.random(), this won't write entries in the journal
     random_uuid = ctx.uuid()
 
+    # To get a timestamp, use ctx.time()
+    # This will record the timestamp in the Restate journal
+    now = await ctx.time()
+
+    # You can convert it to date/datetime using Python's standard library functions, e.g.
+    now_datetime = datetime.fromtimestamp(now)
+
+    # Or to perform a difference:
+    # start = await ctx.time()
+    # # Some code
+    # end = await ctx.time()
+    # delta = datetime.timedelta(seconds=(end-start))
+
     return (f"Hello {name} with "
             f"random number {random_number}, "
             f"random bytes {random_bytes!r} "
-            f"and uuid {random_uuid}!")
+            f"random uuid {random_uuid},"
+            f"now datetime {now_datetime}!")

python/restate/context.py

@@ -237,6 +237,14 @@ def uuid(self) -> UUID:
         This UUID will be stable across retries and replays.
         """
 
+    @abc.abstractmethod
+    def time(self) -> RestateDurableFuture[float]:
+        """
+        Returns the result of time.time(), durably recorded in the journal.
+
+        This timestamp will be stable across retries and replays.
+        """
+
     @typing_extensions.deprecated("`run` is deprecated, use `run_typed` instead for better type safety")
     @overload
     @abc.abstractmethod

python/restate/server_context.py

@@ -26,6 +26,7 @@
 import typing
 import traceback
 from uuid import UUID
+import time
 
 from restate.context import DurablePromise, AttemptFinishedEvent, HandlerType, ObjectContext, Request, RestateDurableCallFuture, RestateDurableFuture, RunAction, SendHandle, RestateDurableSleepFuture, RunOptions, P
 from restate.exceptions import TerminalError
@@ -480,6 +481,9 @@ def random(self) -> Random:
     def uuid(self) -> UUID:
         return UUID(int=self.random_instance.getrandbits(128), version=4)
 
+    def time(self) -> RestateDurableFuture[float]:
+        return self.run_typed("timestamp", time.time)
+
     # pylint: disable=R0914
     async def create_run_coroutine(self,
                                    handle: int,