ovn-controller: Add a generic way to check if the daemon started rece…

…ntly.

In some cases we need to know if ovn-controller started long enough and
has enough iterations of input processing, primarily to ensure it has
downloaded and handled a complete initial view of the SB DB (and of
course the local OVS DB), so that it won't delete things too early by
mistake based on incomplete data.

The mechanism will be used in follow up patches.

Suggested-by: Dumitru Ceara <[email protected]>
Signed-off-by: Han Zhou <[email protected]>
Acked-by: Dumitru Ceara <[email protected]>

TODO.rst

@@ -172,3 +172,10 @@ OVN To-do List
   * Multi-threaded logical flow computation was optimized for the case
     when datapath groups are disabled.  Datpath groups are always enabled
     now so northd parallel processing should be revisited.
+
+* ovn-controller daemon module
+
+  * Dumitru Ceara: Add a new module e.g. ovn/lib/daemon-ovn.c that wraps
+    OVS' daemonize_start() call and initializes the additional things, like
+    the unixctl commands. Or, we should move the APIs such as
+    daemon_started_recently() to OVS's lib/daemon.

controller/ovn-controller.c

@@ -94,6 +94,7 @@ static unixctl_cb_func debug_dump_lflow_conj_ids;
 static unixctl_cb_func lflow_cache_flush_cmd;
 static unixctl_cb_func lflow_cache_show_stats_cmd;
 static unixctl_cb_func debug_delay_nb_cfg_report;
+static unixctl_cb_func debug_ignore_startup_delay;
 
 #define DEFAULT_BRIDGE_NAME "br-int"
 #define DEFAULT_DATAPATH "system"
@@ -866,11 +867,12 @@ static void
 store_nb_cfg(struct ovsdb_idl_txn *sb_txn, struct ovsdb_idl_txn *ovs_txn,
              const struct sbrec_chassis_private *chassis,
              const struct ovsrec_bridge *br_int,
-             unsigned int delay_nb_cfg_report, int64_t startup_ts)
+             unsigned int delay_nb_cfg_report)
 {
     struct ofctrl_acked_seqnos *acked_nb_cfg_seqnos =
         ofctrl_acked_seqnos_get(ofctrl_seq_type_nb_cfg);
     uint64_t cur_cfg = acked_nb_cfg_seqnos->last_acked;
+    int64_t startup_ts = daemon_startup_ts();
 
     if (ovs_txn && br_int
             && startup_ts != smap_get_ullong(&br_int->external_ids,
@@ -3858,6 +3860,9 @@ main(int argc, char *argv[])
                              debug_dump_lflow_conj_ids,
                              &lflow_output_data->conj_ids);
 
+    unixctl_command_register("debug/ignore-startup-delay", "", 0, 0,
+                             debug_ignore_startup_delay, NULL);
+
     unsigned int ovs_cond_seqno = UINT_MAX;
     unsigned int ovnsb_cond_seqno = UINT_MAX;
     unsigned int ovnsb_expected_cond_seqno = UINT_MAX;
@@ -3879,7 +3884,6 @@ main(int argc, char *argv[])
     /* Main loop. */
     exiting = false;
     restart = false;
-    int64_t startup_ts = time_wall_msec();
     bool sb_monitor_all = false;
     while (!exiting) {
         memory_run();
@@ -4059,6 +4063,10 @@ main(int argc, char *argv[])
                     }
                     stopwatch_stop(CONTROLLER_LOOP_STOPWATCH_NAME,
                                    time_msec());
+                    if (engine_has_updated()) {
+                        daemon_started_recently_countdown();
+                    }
+
                     ct_zones_data = engine_get_data(&en_ct_zones);
                     if (ovs_idl_txn) {
                         if (ct_zones_data) {
@@ -4221,7 +4229,7 @@ main(int argc, char *argv[])
             }
 
             store_nb_cfg(ovnsb_idl_txn, ovs_idl_txn, chassis_private,
-                         br_int, delay_nb_cfg_report, startup_ts);
+                         br_int, delay_nb_cfg_report);
 
             if (pending_pkt.conn) {
                 struct ed_type_addr_sets *as_data =
@@ -4698,3 +4706,11 @@ debug_dump_lflow_conj_ids(struct unixctl_conn *conn, int argc OVS_UNUSED,
     unixctl_command_reply(conn, ds_cstr(&conj_ids_dump));
     ds_destroy(&conj_ids_dump);
 }
+
+static void
+debug_ignore_startup_delay(struct unixctl_conn *conn, int argc OVS_UNUSED,
+                           const char *argv[] OVS_UNUSED, void *arg OVS_UNUSED)
+{
+    daemon_started_recently_ignore();
+    unixctl_command_reply(conn, NULL);
+}

lib/inc-proc-eng.c

@@ -312,6 +312,17 @@ engine_has_run(void)
     return false;
 }
 
+bool
+engine_has_updated(void)
+{
+    for (size_t i = 0; i < engine_n_nodes; i++) {
+        if (engine_nodes[i]->state == EN_UPDATED) {
+            return true;
+        }
+    }
+    return false;
+}
+
 bool
 engine_aborted(void)
 {

lib/inc-proc-eng.h

@@ -238,6 +238,10 @@ bool engine_node_changed(struct engine_node *node);
 /* Return true if the engine has run in the last iteration. */
 bool engine_has_run(void);
 
+/* Return true if the engine has any update in any node, i.e. any input
+ * has changed; false if nothing has changed. */
+bool engine_has_updated(void);
+
 /* Returns true if during the last engine run we had to abort processing. */
 bool engine_aborted(void);
 

lib/ovn-util.c

@@ -883,3 +883,55 @@ get_bridge(const struct ovsrec_bridge_table *bridge_table, const char *br_name)
     }
     return NULL;
 }
+
+#define DAEMON_STARTUP_DELAY_SEED 20
+#define DAEMON_STARTUP_DELAY_MS   10000
+
+static int64_t startup_ts;
+static int startup_delay = DAEMON_STARTUP_DELAY_SEED;
+
+/* Used by debug command only, for tests. */
+static bool ignore_startup_delay = false;
+
+OVS_CONSTRUCTOR(startup_ts_initializer) {
+    startup_ts = time_wall_msec();
+}
+
+int64_t
+daemon_startup_ts(void)
+{
+    return startup_ts;
+}
+
+void
+daemon_started_recently_countdown(void)
+{
+    if (startup_delay > 0) {
+        startup_delay--;
+    }
+}
+
+void
+daemon_started_recently_ignore(void)
+{
+    ignore_startup_delay = true;
+}
+
+bool
+daemon_started_recently(void)
+{
+    if (ignore_startup_delay) {
+        return false;
+    }
+
+    VLOG_DBG("startup_delay: %d, startup_ts: %"PRId64, startup_delay,
+             startup_ts);
+
+    /* Ensure that at least an amount of updates has been handled. */
+    if (startup_delay) {
+        return true;
+    }
+
+    /* Ensure that at least an amount of time has passed. */
+    return time_wall_msec() - startup_ts <= DAEMON_STARTUP_DELAY_MS;
+}

lib/ovn-util.h

@@ -309,5 +309,9 @@ struct ovsrec_bridge_table;
 const struct ovsrec_bridge *get_bridge(const struct ovsrec_bridge_table *,
                                        const char *br_name);
 
+void daemon_started_recently_countdown(void);
+void daemon_started_recently_ignore(void);
+bool daemon_started_recently(void);
+int64_t daemon_startup_ts(void);
 
 #endif /* OVN_UTIL_H */