ci/ci_gantt_chart: add option to save output to a file

Allow saving in html and in image formats.

Signed-off-by: Helen Koike <helen.koike@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25793>

bin/ci/ci_gantt_chart.py

@@ -114,6 +114,12 @@ def parse_args() -> None:
         description="Generate the Gantt chart from a given pipeline."
     )
     parser.add_argument("pipeline_url", type=str, help="URLs to the pipeline.")
+    parser.add_argument(
+        "-o",
+        "--output",
+        type=str,
+        help="Output file name. Use html ou image suffixes to choose the format.",
+    )
     parser.add_argument(
         "--token",
         metavar="token",
@@ -131,4 +137,10 @@ if __name__ == "__main__":
 
     pipeline, _ = get_gitlab_pipeline_from_url(gl, args.pipeline_url)
     fig = generate_gantt_chart(pipeline)
-    fig.show()
+    if args.output and "htm" in args.output:
+        fig.write_html(args.output)
+    elif args.output:
+        fig.update_layout(width=1000)
+        fig.write_image(args.output)
+    else:
+        fig.show()