vlog: add "vlog/list-pattern" command

This patch allows to query logging format at the runtime for each destination
with "vlog/list-pattern" command.

Signed-off-by: Ansis Atteka <aatteka@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>

NEWS

@@ -119,6 +119,8 @@ v2.4.0 - xx xxx xxxx
      See ovs-sim(1) for more information.
    - Support to configure method (--syslog-method argument) that determines
      how daemons will talk with syslog.
+   - Support for "ovs-appctl vlog/list-pattern" command that lets to query
+     logging message format for each destination.
 
 
 v2.3.0 - 14 Aug 2014

include/openvswitch/vlog.h

@@ -133,6 +133,7 @@ void vlog_set_levels(struct vlog_module *,
 char *vlog_set_levels_from_string(const char *) OVS_WARN_UNUSED_RESULT;
 void vlog_set_levels_from_string_assert(const char *);
 char *vlog_get_levels(void);
+char *vlog_get_patterns(void);
 bool vlog_is_enabled(const struct vlog_module *, enum vlog_level);
 bool vlog_should_drop(const struct vlog_module *, enum vlog_level,
                       struct vlog_rate_limit *);

lib/vlog-unixctl.man

@@ -51,6 +51,9 @@ Sets the log pattern for \fIdestination\fR to \fIpattern\fR.  Refer to
 .IP "\fBvlog/list\fR"
 Lists the supported logging modules and their current levels.
 .
+.IP "\fBvlog/list-pattern\fR"
+Lists logging patterns used for each destination.
+.
 .IP "\fBvlog/reopen\fR"
 Causes \fB\*(PN\fR to close and reopen its log file.  (This is useful
 after rotating log files, to cause a new log file to be used.)

lib/vlog.c

@@ -614,6 +614,17 @@ vlog_unixctl_list(struct unixctl_conn *conn, int argc OVS_UNUSED,
     free(msg);
 }
 
+static void
+vlog_unixctl_list_pattern(struct unixctl_conn *conn, int argc OVS_UNUSED,
+                          const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
+{
+    char *msg;
+
+    msg = vlog_get_patterns();
+    unixctl_command_reply(conn, msg);
+    free(msg);
+}
+
 static void
 vlog_unixctl_reopen(struct unixctl_conn *conn, int argc OVS_UNUSED,
                     const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
@@ -721,6 +732,8 @@ vlog_init(void)
             1, INT_MAX, vlog_unixctl_set, NULL);
         unixctl_command_register("vlog/list", "", 0, 0, vlog_unixctl_list,
                                  NULL);
+        unixctl_command_register("vlog/list-pattern", "", 0, 0,
+                                 vlog_unixctl_list_pattern, NULL);
         unixctl_command_register("vlog/enable-rate-limit", "[module]...",
                                  0, INT_MAX, vlog_enable_rate_limit, NULL);
         unixctl_command_register("vlog/disable-rate-limit", "[module]...",
@@ -785,6 +798,32 @@ vlog_get_levels(void)
     return ds_cstr(&s);
 }
 
+/* Returns as a string current logging patterns for each destination.
+ * This string must be released by caller. */
+char *
+vlog_get_patterns(void)
+{
+    struct ds ds = DS_EMPTY_INITIALIZER;
+    enum vlog_destination destination;
+
+    ovs_rwlock_rdlock(&pattern_rwlock);
+    ds_put_format(&ds, "         prefix                            format\n");
+    ds_put_format(&ds, "         ------                            ------\n");
+
+    for (destination = 0; destination < VLF_N_DESTINATIONS; destination++) {
+        struct destination *f = &destinations[destination];;
+        const char *prefix = "none";
+
+        if (destination == VLF_SYSLOG && syslogger) {
+            prefix = syslog_get_prefix(syslogger);
+        }
+        ds_put_format(&ds, "%-7s  %-32s  %s\n", f->name, prefix, f->pattern);
+    }
+    ovs_rwlock_unlock(&pattern_rwlock);
+
+    return ds_cstr(&ds);
+}
+
 /* Returns true if a log message emitted for the given 'module' and 'level'
  * would cause some log output, false if that module and level are completely
  * disabled. */

utilities/ovs-appctl.8.in

@@ -112,6 +112,9 @@ and adjusting log levels.
 .IP "\fBvlog/list\fR"
 Lists the known logging modules and their current levels.
 .
+.IP "\fBvlog/list-pattern\fR"
+Lists logging pattern used for each destination.
+.
 .IP "\fBvlog/set\fR [\fIspec\fR]"
 Sets logging levels.  Without any \fIspec\fR, sets the log level for
 every module and destination to \fBdbg\fR.  Otherwise, \fIspec\fR is a

utilities/ovs-appctl.c

@@ -92,6 +92,7 @@ Common commands:\n\
   list-commands      List commands supported by the target\n\
   version            Print version of the target\n\
   vlog/list          List current logging levels\n\
+  vlog/list-pattern  List logging patterns for each destination.\n\
   vlog/set [SPEC]\n\
       Set log levels as detailed in SPEC, which may include:\n\
       A valid module name (all modules, by default)\n\