Add dry run argument

mailman_sync.py

@@ -11,19 +11,24 @@ import subprocess
 import requests
 
 
-def sync_members(mailman_bin: Path, mailing_list: str, members: list[str]):
+def sync_members(
+    mailman_bin: Path, mailing_list: str, members: list[str], dry_run: bool
+):
+    command = [
+        mailman_bin / "sync_members",
+        "--welcome-msg=no",
+        "--goodbye-msg=no",
+        "--notifyadmin=no",
+        "--file",
+        "-",
+        mailing_list,
+    ]
+    if dry_run:
+        command.append("--no-change")
+
     members_data = "\n".join(members)
     output = subprocess.run(
-        [
-            mailman_bin / "sync_members",
-            "--no-change",
-            "--welcome-msg=no",
-            "--goodbye-msg=no",
-            "--notifyadmin=no",
-            "--file",
-            "-",
-            mailing_list,
-        ],
+        command,
         input=members_data,
         encoding="ascii",
         capture_output=True,
@@ -32,7 +37,7 @@ def sync_members(mailman_bin: Path, mailing_list: str, members: list[str]):
     print(output.stdout)
 
 
-def main(mailman_bin: Path, api: str, token: str, list_suffix: str):
+def main(mailman_bin: Path, api: str, token: str, list_suffix: str, dry_run: bool):
     r = requests.get(api, headers={"Authorization": "Token " + token})
     if not r.ok:
         print(f"Failed to get mailing list data from api: {r.status_code} {r.text}")
@@ -48,7 +53,7 @@ def main(mailman_bin: Path, api: str, token: str, list_suffix: str):
     for name, members in certification_lists.items():
         list_name = name + list_suffix
         if list_name in existing_lists:
-            sync_members(mailman_bin, list_name, members)
+            sync_members(mailman_bin, list_name, members, dry_run)
         else:
             print(f"Skipping {list_name}, as it does not exist in Mailman")
 
@@ -64,10 +69,16 @@ if __name__ == "__main__":
     argp.add_argument("--api", required=True, help="API endpoint to retrieve JSON from")
     argp.add_argument("--token", required=True, help="Authorization Token for API")
     argp.add_argument("--list-suffix", help="Suffix for mailing lists")
+    argp.add_argument(
+        "-n",
+        "--dry-run",
+        action="store_true",
+        help="Don't make changes, just print what would happen",
+    )
     args = argp.parse_args()
 
     try:
-        main(args.bin, args.api, args.token, args.list_suffix)
+        main(args.bin, args.api, args.token, args.list_suffix, args.dry_run)
     except subprocess.CalledProcessError as e:
         print(e.stderr)
         raise