Added concurrent export example

examples/concurrent_export.py

@@ -0,0 +1,50 @@
+"""Example for concurrent export of photos using osxphotos.PhotoExporter.export()
+
+Note: concurrent export can only be used on Python 3.11 and later due to the way
+python's sqlite3 module is implemented. See https://docs.python.org/3/library/sqlite3.html#sqlite3.threadsafety
+for more information.
+"""
+
+import concurrent.futures
+import os
+import time
+
+import click
+
+import osxphotos
+from osxphotos.cli import echo, query_command, verbose
+
+
+@query_command()
+@click.option(
+    "--workers",
+    metavar="WORKERS",
+    help="Maximum number of worker threads to use for export. "
+    "If not specified, it will default to the number of processors on the machine, multiplied by 5.",
+    type=int,
+)
+@click.argument(
+    "export_dir",
+    type=click.Path(exists=True, file_okay=False, dir_okay=True, writable=True),
+)
+def export(workers, export_dir, photos: list[osxphotos.PhotoInfo], **kwargs):
+    """Export photos"""
+    workers = workers or os.cpu_count() * 5
+    echo(f"Exporting {len(photos)} photos to {export_dir} using {workers} workers")
+    start_t = time.perf_counter()
+    with concurrent.futures.ThreadPoolExecutor(max_workers=workers) as executor:
+        futures = [
+            executor.submit(p.export, export_dir, f"{p.uuid}_{p.original_filename}")
+            for p in photos
+        ]
+        exported = []
+        for future in concurrent.futures.as_completed(futures):
+            exported.extend(future.result())
+    end_t = time.perf_counter()
+    echo(
+        f"Exported {len(exported)} photos to {export_dir} in {end_t-start_t:.4f} seconds"
+    )
+
+
+if __name__ == "__main__":
+    export()