Add offline runners info in the Slack report (#19169)

* send slack report for offline runners

Co-authored-by: ydshieh <ydshieh@users.noreply.github.com>

utils/check_self_hosted_runner.py

@@ -5,6 +5,8 @@ import subprocess
 
 def get_runner_status(target_runners, token):
 
+    offline_runners = []
+
     cmd = (
         f'curl -H "Accept: application/vnd.github+json" -H "Authorization: Bearer {token}"'
         " https://api.github.com/repos/huggingface/transformers/actions/runners"
@@ -17,7 +19,15 @@ def get_runner_status(target_runners, token):
     for runner in runners:
         if runner["name"] in target_runners:
             if runner["status"] == "offline":
-                raise ValueError(f"{runner['name']} is offline!")
+                offline_runners.append(runner)
+
+    # save the result so we can report them on Slack
+    with open("offline_runners.txt", "w") as fp:
+        fp.write(json.dumps(offline_runners))
+
+    if len(offline_runners) > 0:
+        failed = "\n".join(offline_runners)
+        raise ValueError(f"The following runners are offline:\n{failed}")
 
 
 if __name__ == "__main__":