maintenance: use random minute in cron scheduler

The get_random_minute() method was created to allow maintenance
schedules to be fixed to a random minute of the hour. This randomness is
only intended to spread out the load from a number of clients, but each
client should have an hour between each maintenance cycle.

Add this random minute to the cron integration.

The cron schedule specification starts with a minute indicator, which
was previously inserted as the "0" string but now takes the given minute
as an integer parameter.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/gc.c b/builtin/gc.c
index 78924bb32c62b518268de004831be62a954a94bf..ef8bb772c3845ae3562cccf9f876f1c42a3b0536 100644 (file)
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -2174,6 +2174,7 @@ static int crontab_update_schedule(int run_maintenance, int fd)
        FILE *cron_list, *cron_in;
        struct strbuf line = STRBUF_INIT;
        struct tempfile *tmpedit = NULL;
+       int minute = get_random_minute();
 
        get_schedule_cmd(&cmd, NULL);
        strvec_split(&crontab_list.args, cmd);
@@ -2228,11 +2229,11 @@ static int crontab_update_schedule(int run_maintenance, int fd)
                        "# replaced in the future by a Git command.\n\n");
 
                strbuf_addf(&line_format,
-                           "%%s %%s * * %%s \"%s/git\" --exec-path=\"%s\" for-each-repo --config=maintenance.repo maintenance run --schedule=%%s\n",
+                           "%%d %%s * * %%s \"%s/git\" --exec-path=\"%s\" for-each-repo --config=maintenance.repo maintenance run --schedule=%%s\n",
                            exec_path, exec_path);
-               fprintf(cron_in, line_format.buf, "0", "1-23", "*", "hourly");
-               fprintf(cron_in, line_format.buf, "0", "0", "1-6", "daily");
-               fprintf(cron_in, line_format.buf, "0", "0", "0", "weekly");
+               fprintf(cron_in, line_format.buf, minute, "1-23", "*", "hourly");
+               fprintf(cron_in, line_format.buf, minute, "0", "1-6", "daily");
+               fprintf(cron_in, line_format.buf, minute, "0", "0", "weekly");
                strbuf_release(&line_format);
 
                fprintf(cron_in, "\n%s\n", END_LINE);