Fix: add some sane default values to --live opt

[lttng-tools.git] / src / bin / lttng / commands / create.c

diff --git a/src/bin/lttng/commands/create.c b/src/bin/lttng/commands/create.c
index d234c06a4f3f12afd891fce9e6e67b579d9e2483..2e03373266c2ca9c3d10f469bfb5da9ef3a5dfb6 100644 (file)
--- a/src/bin/lttng/commands/create.c
+++ b/src/bin/lttng/commands/create.c
@@ -65,7 +65,7 @@ static struct poptOption long_options[] = {
        {"no-consumer",     0, POPT_ARG_VAL, &opt_no_consumer, 1, 0, 0},
        {"disable-consumer", 0, POPT_ARG_VAL, &opt_disable_consumer, 1, 0, 0},
        {"snapshot",        0, POPT_ARG_VAL, &opt_snapshot, 1, 0, 0},
-       {"live",            0, POPT_ARG_INT, 0, OPT_LIVE_TIMER, 0, 0},
+       {"live",            0, POPT_ARG_INT | POPT_ARGFLAG_OPTIONAL, 0, OPT_LIVE_TIMER, 0, 0},
        {0, 0, 0, 0, 0, 0, 0}
 };
 
@@ -95,11 +95,14 @@ static void usage(FILE *ofp)
        fprintf(ofp, "                       if one, as the default snapshot output.\n");
        fprintf(ofp, "                       Every channel will be set in overwrite mode\n");
        fprintf(ofp, "                       and with mmap output (splice not supported).\n");
-       fprintf(ofp, "      --live USEC      Set the session in live-reading mode.\n");
+       fprintf(ofp, "      --live [USEC]    Set the session in live-reading mode.\n");
        fprintf(ofp, "                       The delay parameter in micro-seconds is the\n");
        fprintf(ofp, "                       maximum time the user can wait for the data\n");
-       fprintf(ofp, "                       to be flushed. Requires a network URL (-U or -C/-D)\n");
-       fprintf(ofp, "                       and a lttng-relayd listening.\n");
+       fprintf(ofp, "                       to be flushed. Can be set with a network\n");
+       fprintf(ofp, "                       URL (-U or -C/-D) and must have a relayd listening.\n");
+       fprintf(ofp, "                       By default, %u is used for the timer and the\n",
+                                                                                       DEFAULT_LTTNG_LIVE_TIMER);
+       fprintf(ofp, "                       network URL is set to net://127.0.0.1.\n");
        fprintf(ofp, "\n");
        fprintf(ofp, "Extended Options:\n");
        fprintf(ofp, "\n");
@@ -344,9 +347,15 @@ static int create_session(void)
        }
 
        if ((opt_live_timer && !opt_url) && (opt_live_timer && !opt_data_url)) {
-               ERR("You need a network URL (-U or -C/-D) to use live tracing.");
-               ret = CMD_ERROR;
-               goto error;
+               /* Use default live URL if none is found. */
+               ret = asprintf(&alloc_url, "net://127.0.0.1");
+               if (ret < 0) {
+                       PERROR("asprintf default live URL");
+                       ret = CMD_FATAL;
+                       goto error;
+               }
+               url = alloc_url;
+               print_str_url = url;
        }
 
        if (opt_snapshot && opt_live_timer) {
@@ -401,6 +410,10 @@ static int create_session(void)
        MSG("Session %s created.", session_name);
        if (print_str_url && !opt_snapshot) {
                MSG("Traces will be written in %s", print_str_url);
+
+               if (opt_live_timer) {
+                       MSG("Live timer set to %u usec", opt_live_timer);
+               }
        } else if (opt_snapshot) {
                if (print_str_url) {
                        MSG("Default snapshot output set to: %s", print_str_url);
@@ -457,6 +470,14 @@ int cmd_create(int argc, const char **argv)
 
                        errno = 0;
                        opt_arg = poptGetOptArg(pc);
+                       if (!opt_arg) {
+                               /* Set up default values. */
+                               opt_live_timer = (uint32_t) DEFAULT_LTTNG_LIVE_TIMER;
+                               DBG("Session live timer interval set to default value %d",
+                                               opt_live_timer);
+                               break;
+                       }
+
                        v = strtoul(opt_arg, NULL, 0);
                        if (errno != 0 || !isdigit(opt_arg[0])) {
                                ERR("Wrong value in --live parameter: %s", opt_arg);