From: Christian Herdtweck <christian.herdtweck@intra2net.com>
Date: Thu, 8 May 2014 12:51:37 +0000 (+0200)
Subject: if DNS request at start of ping fails, re-schedule further requests; originally faile... 
X-Git-Url: http://developer.intra2net.com/git/?a=commitdiff_plain;h=3f6ba9249f48a76c2fd35a83b8bf59b50a94cd5d;p=pingcheck

if DNS request at start of ping fails, re-schedule further requests; originally failed at once and never tried again
---

diff --git a/src/host/pingscheduler.cpp b/src/host/pingscheduler.cpp
index 22502ac..9306467 100644
--- a/src/host/pingscheduler.cpp
+++ b/src/host/pingscheduler.cpp
@@ -71,8 +71,10 @@ PingScheduler::PingScheduler(
 ) :
     IoService(),
     NextPingTimer( IoService ),
+    NextAddressTimer( IoService ),
     TimeSentLastPing( microsec_clock::universal_time() ),
     PingIntervalInSec( ping_interval_in_sec ),
+    AddressResolveIntervalInSec( ping_interval_in_sec ),
     HostAnalyzer( destination_address, ping_fail_percentage_limit, link_analyzer ),
     Ping(),
     Thread()
@@ -92,6 +94,7 @@ PingScheduler::PingScheduler(
             destination_port,
             nameserver
     );
+    AddressResolvedFirstTime = false;
 }
 
 /**
@@ -135,8 +138,12 @@ bool PingScheduler::start_pinging()
     bool address_resolved = resolve_ping_address();
     if ( !address_resolved )
     {
-        return false;
+        //return false;
+        // new behaviour: try again later
+        schedule_address_resolve();
     }
+    else
+        AddressResolvedFirstTime = true;
 
     setup_next_ping();
 
@@ -181,6 +188,17 @@ bool PingScheduler::resolve_ping_address()
     return true;
 }
 
+void PingScheduler::schedule_address_resolve()
+{
+    if (resolve_ping_address())
+        AddressResolvedFirstTime = true;
+    else
+    {
+        (void) NextAddressTimer.expires_from_now( seconds( AddressResolveIntervalInSec ) );
+        NextAddressTimer.async_wait( bind( &PingScheduler::schedule_address_resolve, this ) );
+    }
+}
+
 void PingScheduler::ping()
 {
     Ping->ping( boost::bind(&PingScheduler::ping_done_handler, this, _1) );
@@ -196,11 +214,14 @@ void PingScheduler::ping_done_handler( bool ping_success )
 
 void PingScheduler::setup_next_ping()
 {
-    BOOST_ASSERT( 1 <= Ping->get_resolved_ip_count() );
+    if (AddressResolvedFirstTime)
+    {
+        BOOST_ASSERT( 1 <= Ping->get_resolved_ip_count() );
 
-    update_ping_address();
+        update_ping_address();
 
-    ping();
+        ping();
+    }
 }
 
 void PingScheduler::schedule_next_ping()
diff --git a/src/host/pingscheduler.h b/src/host/pingscheduler.h
index e6bf01e..e29af24 100644
--- a/src/host/pingscheduler.h
+++ b/src/host/pingscheduler.h
@@ -74,6 +74,7 @@ private:
 
     void update_ping_address();
     bool resolve_ping_address();
+    void schedule_address_resolve();
 
     void ping();
     void ping_done_handler(bool ping_success);
@@ -93,16 +94,22 @@ private:
     boost::asio::io_service IoService;
     /// Timer to trigger the next ping
     boost::asio::deadline_timer NextPingTimer;
+    /// Timer to trigger the next attempt to resolve addresses
+    boost::asio::deadline_timer NextAddressTimer;
     /// Keeps track of the time when the last ping was send
     boost::posix_time::ptime TimeSentLastPing;
     /// Interval between each ping to the same host
     PingInterval PingIntervalInSec;
+    /// Interval between attempts to resolve host address
+    PingInterval AddressResolveIntervalInSec;
     /// Object responsible to evaluate the status of the host
     HostStatus HostAnalyzer;
     /// Internal boost pinger object
     PingRotateItem Ping;
     /// Thread object
     boost::thread Thread;
+    /// flag that address is resolved, so can start pinging
+    bool AddressResolvedFirstTime;
 
 };