Fix flushing race in new multi-recording SDK (#2125)

* add minimal_options py example and use it in e2e suite (catches 2fast2log races(

* make sure to push goodbye last

crates/re_sdk/src/recording_stream.rs

@@ -783,6 +783,16 @@ impl RecordingStream {
             return;
         };
 
+        // TODO(cmc): The `Goodbye` message is our last remaining message piece that is neither
+        // idempotent, stateless, nor order insensitive... so make sure to get all the pending
+        // tables into the pipe first.
+
+        // 1. Flush the batcher down the table channel
+        this.batcher.flush_blocking();
+
+        // 2. Drain all pending tables from the batcher's channel _before_ any other future command
+        this.cmds_tx.send(Command::PopPendingTables).ok();
+
         this.cmds_tx
             .send(Command::RecordMsg(LogMsg::Goodbye(
                 this.info.recording_id.clone(),

examples/python/minimal_options/main.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+
+"""Demonstrates the most barebone usage of the Rerun SDK, with standard options."""
+
+
+import argparse
+
+import numpy as np
+import rerun as rr
+
+parser = argparse.ArgumentParser(description="Logs rich data using the Rerun SDK.")
+rr.script_add_args(parser)
+args, unknown = parser.parse_known_args()
+[__import__("logging").warning(f"unknown arg: {arg}") for arg in unknown]
+
+rr.script_setup(args, "minimal_options")
+
+positions = np.vstack([xyz.ravel() for xyz in np.mgrid[3 * [slice(-5, 5, 10j)]]]).T
+colors = np.vstack([rgb.ravel() for rgb in np.mgrid[3 * [slice(0, 255, 10j)]]]).astype(np.uint8).T
+
+rr.log_points("my_points", positions=positions, colors=colors)
+
+rr.script_teardown(args)

examples/python/minimal_options/requirements.txt

@@ -0,0 +1,2 @@
+numpy
+rerun-sdk

examples/python/requirements.txt

@@ -7,6 +7,7 @@
 -r dicom/requirements.txt
 -r dna/requirements.txt
 -r minimal/requirements.txt
+-r minimal_options/requirements.txt
 -r mp_pose/requirements.txt
 -r multiprocessing/requirements.txt
 -r multithreading/requirements.txt

scripts/run_python_e2e_test.py

@@ -43,6 +43,7 @@ def main() -> None:
         requirements = [
             "examples/python/api_demo/requirements.txt",
             "examples/python/car/requirements.txt",
+            "examples/python/minimal_options/requirements.txt",
             "examples/python/multithreading/requirements.txt",
             "examples/python/plots/requirements.txt",
             "examples/python/text_logging/requirements.txt",
@@ -61,6 +62,7 @@ def main() -> None:
         # Trivial examples that don't require weird dependencies, or downloading data
         ("examples/python/api_demo/main.py", ["--demo", "all"]),
         ("examples/python/car/main.py", []),
+        ("examples/python/minimal_options/main.py", []),
         ("examples/python/multithreading/main.py", []),
         ("examples/python/plots/main.py", []),
         ("examples/python/text_logging/main.py", []),