Add a common function to get the warm-start timer (sonic-net#589)

* Add common getWarmStartTimer function

* simplify the warm-start timer schema

* Add timer details in the schema and fix a few things in gettimer common function

Author: zhenggen-xu

doc/swss-schema.md

@@ -634,17 +634,18 @@ Equivalent RedisDB entry:
     ;Stores system warm start configuration
     ;Status: work in progress
 
-    key             = WARM_RESTART:name         ; name is the name of SONiC docker or "system" for global configuration.
-
-    enable          = "true" / "false"          ; Default value as false.
-                                                ; If "system" warm start knob is true, docker level knob will be ignored.
-                                                ; If "system" warm start knob is false, docker level knob takes effect.
-
-    timer_name      = 1*255VCHAR,               ; timer_name is the name of warm start timer for the whole system or the specific docker,
-                                                ; Ex. "neighbor_timer", "bgp_timer". The name should not contain "," character.
-                                                ; There could be more than one timer in a docker or the system, separated by ",".
-
-    timer_duration  = 1*4DIGIT,                 ; timer duration, in seconds. Separated by "," if there are more than on timer.
+    key                 = WARM_RESTART:name ; name is the name of SONiC docker or "system" for global configuration.
+
+    enable              = "true" / "false"  ; Default value as false.
+                                            ; If "system" warm start knob is true, docker level knob will be ignored.
+                                            ; If "system" warm start knob is false, docker level knob takes effect.
+
+    neighsyncd_timer    = 1*4DIGIT          ; neighsyncd_timer is the timer used for neighsyncd during the warm restart.
+                                            ; Timer is started after we restored the neighborTable to internal data structures.
+                                            ; neighborsyncd then starts to read all linux kernel entries and mark the entries in
+                                            ; the data structures accordingly. Once the timer is expired, we will do reconciliation
+                                            ; and push the delta to appDB
+                                            ; Valid value is 1-9999. 0 is invalid.
 
 
 ## State DB schema

warmrestart/warm_restart.cpp

@@ -1,6 +1,7 @@
 #include <string>
 #include "logger.h"
 #include "schema.h"
+#include <climits>
 #include "warm_restart.h"
 
 namespace swss {
@@ -96,6 +97,34 @@ bool WarmStart::checkWarmStart(const std::string &app_name, const std::string &d
     return true;
 }
 
+/*
+ * Get warmStartTimer for an application in a docker (default to be swss)
+ * return timer value. Value 0 means invalid.
+ */
+uint32_t WarmStart::getWarmStartTimer(const std::string &app_name,
+    const std::string &docker_name)
+{
+    auto& warmStart = getInstance();
+    std::string timer_name = app_name + "_timer";
+    std::string timer_value_str;
+
+    warmStart.m_cfgWarmRestartTable->hget(docker_name, timer_name, timer_value_str);
+
+    unsigned long int temp_value = strtoul(timer_value_str.c_str(), NULL, 0);
+    if (temp_value != 0 && temp_value != ULONG_MAX && temp_value <= MAXIMUN_WARMRESTART_TIMER_VALUE)
+    {
+        SWSS_LOG_NOTICE("Getting warmStartTimer for docker: %s, app: %s, value: %lu",
+                docker_name.c_str(), app_name.c_str(), temp_value);
+        return (uint32_t)temp_value;
+    }
+    else
+    {
+        SWSS_LOG_NOTICE("warmStartTimer is not configured or invalid for docker: %s, app: %s",
+                docker_name.c_str(), app_name.c_str());
+        return 0;
+    }
+}
+
 bool WarmStart::isWarmStart()
 {
     auto& warmStart = getInstance();

warmrestart/warm_restart.h

@@ -5,6 +5,8 @@
 #include "dbconnector.h"
 #include "table.h"
 
+#define MAXIMUN_WARMRESTART_TIMER_VALUE 9999
+
 namespace swss {
 
 class WarmStart
@@ -23,6 +25,8 @@ class WarmStart
     static WarmStart &getInstance();
 
     static bool checkWarmStart(const std::string &app_name, const std::string &docker_name = "swss");
+    static uint32_t getWarmStartTimer(const std::string &app_name,
+        const std::string &docker_name ="swss");
     static bool isWarmStart();
     static void setWarmStartState(const std::string &app_name, WarmStartState state);
 private: