add python example

Author: teh-cmc

examples/python/external_data_loader/README.md

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+---
+title: External data-loader example
+python: https://github.com/rerun-io/rerun/tree/latest/examples/python/external_data_loader/main.py?speculative-link
+rust: https://github.com/rerun-io/rerun/tree/latest/examples/rust/external_data_loader/src/main.rs?speculative-link
+cpp: https://github.com/rerun-io/rerun/tree/latest/examples/cpp/external_data_loader/main.cpp?speculative-link
+thumbnail: https://static.rerun.io/external_data_loader_rust/45b1312910063086708d2db52dc3eb619e741d8c/480w.png
+---
+
+<picture>
+  <img src="https://static.rerun.io/external_data_loader_rust/45b1312910063086708d2db52dc3eb619e741d8c/full.png" alt="">
+  <source media="(max-width: 480px)" srcset="https://static.rerun.io/external_data_loader_rust/45b1312910063086708d2db52dc3eb619e741d8c/480w.png">
+  <source media="(max-width: 768px)" srcset="https://static.rerun.io/external_data_loader_rust/45b1312910063086708d2db52dc3eb619e741d8c/768w.png">
+  <source media="(max-width: 1024px)" srcset="https://static.rerun.io/external_data_loader_rust/45b1312910063086708d2db52dc3eb619e741d8c/1024w.png">
+  <source media="(max-width: 1200px)" srcset="https://static.rerun.io/external_data_loader_rust/45b1312910063086708d2db52dc3eb619e741d8c/1200w.png">
+</picture>
+
+This is an example executable data-loader plugin for the Rerun Viewer.
+
+It will log Python source code files as markdown documents.
+To try it out, copy it in your $PATH as `rerun-loader-python-file`, then open a Python source file with Rerun (`rerun file.py`).

examples/python/external_data_loader/main.py

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+#!/usr/bin/env python3
+"""Example of an executable data-loader plugin for the Rerun Viewer."""
+from __future__ import annotations
+
+import argparse
+import os
+
+import rerun as rr  # pip install rerun-sdk
+
+# The Rerun Viewer will always pass these two pieces of information:
+# 1. The path to be loaded, as a positional arg.
+# 2. A shared recording ID, via the `--recording-id` flag.
+#
+# It is up to you whether you make use of that shared recording ID or not.
+# If you use it, the data will end up in the same recording as all other plugins interested in
+# that file, otherwise you can just create a dedicated recording for it. Or both.
+parser = argparse.ArgumentParser(
+    description="""
+This is an example executable data-loader plugin for the Rerun Viewer.
+
+It will log Python source code files as markdown documents.
+To try it out, copy it in your $PATH as `rerun-loader-python-file`, then open a Python source file with Rerun (`rerun file.py`).
+"""
+)
+parser.add_argument("filepath", type=str)
+parser.add_argument("--recording-id", type=str)
+args = parser.parse_args()
+
+
+def main() -> None:
+    is_file = os.path.isfile(args.filepath)
+    is_rust_file = os.path.splitext(args.filepath)[1].lower() == ".py"
+
+    # We're not interested: just exit silently.
+    # Don't return an error, as that would show up to the end user in the Rerun Viewer!
+    if not (is_file and is_rust_file):
+        return
+
+    rr.init("rerun_example_external_loader", recording_id=args.recording_id)
+    # The most important part of this: log to standard output so the Rerun Viewer can ingest it!
+    rr.stdout()
+
+    with open(args.filepath) as file:
+        body = file.read()
+        text = f"""## Some Python code\n```python\n{body}\n```\n"""
+        rr.log(args.filepath, rr.TextDocument(text, media_type=rr.MediaType.MARKDOWN), timeless=True)
+
+
+if __name__ == "__main__":
+    main()

examples/python/external_data_loader/requirements.txt

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+rerun-sdk