This patch introduces "fast shutdown" mode and two new signals.

-- kevin brintnall

git-svn-id: svn://svn.oetiker.ch/rrdtool/trunk/program@1540 a5681a0c-68f1-0310-ab6d-d61299d08faa

diff --git a/doc/rrdcached.pod b/doc/rrdcached.pod
index d8d88c5..8ed2979 100644 (file)
--- a/doc/rrdcached.pod
+++ b/doc/rrdcached.pod
@@ -6,7 +6,7 @@ rrdcached - Data caching daemon for rrdtool
 
 =head1 SYNOPSIS
 
 
 =head1 SYNOPSIS
 

-B<rrdcached> [B<-l> I<address>] [B<-w> I<timeout>] [B<-z> I<delay>] [B<-f> I<timeout>] [B<-j> I<dir>]
+B<rrdcached> [B<-l> I<address>] [B<-w> I<timeout>] [B<-z> I<delay>] [B<-f> I<timeout>] [B<-j> I<dir>] [-F]

 
 =head1 DESCRIPTION
 
 
 =head1 DESCRIPTION
 


@@ -87,7 +87,20 @@ found, all updates therein will be read into memory before the daemon
 starts accepting new connections.
 
 The journal will be rotated with the same frequency as the flush timer
 starts accepting new connections.
 
 The journal will be rotated with the same frequency as the flush timer

-given by B<-f>.  On clean shutdown, the journal files are removed.
+given by B<-f>.
+
+When journaling is enabled, the daemon will use a fast shutdown procedure.
+Rather than flushing all files to disk, it will make sure the journal is
+properly written and exit immediately.  Although the RRD data files are
+not fully up-to-date, no information is lost; all pending updates will be
+replayed from the journal next time the daemon starts up.
+
+To disable fast shutdown, use the B<-F> option.
+
+=item B<-F>
+
+ALWAYS flush all updates to the RRD data files when the daemon is shut
+down, regardless of journal setting.

 
 =item B<-b> I<dir>
 
 
 =item B<-b> I<dir>
 


@@ -421,6 +434,29 @@ Number of times the journal has been rotated since startup.
 
 =item SIGINT and SIGTERM
 
 
 =item SIGINT and SIGTERM
 

+The daemon exits normally on receipt of either of these signals.  Pending
+updates are handled in accordance with the B<-j> and B<-F> options.
+
+=item SIGUSR1
+
+The daemon exits AFTER flushing all updates out to disk.  This may take a
+while.
+
+=item SIGUSR2
+
+The daemon exits immediately, without flushing updates out to disk.
+Pending updates will be replayed from the journal when the daemon starts
+up again.  B<WARNING: if journaling (-j) is NOT enabled, any pending
+updates WILL BE LOST>.
+
+=back
+
+=head1 SIGNALS
+
+=over 4
+
+=item SIGINT and SIGTERM
+

 The daemon exits normally on receipt of either of these signals.
 
 =back
 The daemon exits normally on receipt of either of these signals.
 
 =back

diff --git a/src/rrd_daemon.c b/src/rrd_daemon.c
index a0b8364..e0e373a 100644 (file)
--- a/src/rrd_daemon.c
+++ b/src/rrd_daemon.c
@@ -168,6 +168,7 @@ static pthread_cond_t  cache_cond = PTHREAD_COND_INITIALIZER;
 static int config_write_interval = 300;
 static int config_write_jitter   = 0;
 static int config_flush_interval = 3600;
 static int config_write_interval = 300;
 static int config_write_jitter   = 0;
 static int config_flush_interval = 3600;

+static int config_flush_at_shutdown = 0;

 static char *config_pid_file = NULL;
 static char *config_base_dir = NULL;
 
 static char *config_pid_file = NULL;
 static char *config_base_dir = NULL;
 


@@ -212,6 +213,18 @@ static void sig_term_handler (int s __attribute__((unused))) /* {{{ */
   sig_common("TERM");
 } /* }}} void sig_term_handler */
 
   sig_common("TERM");
 } /* }}} void sig_term_handler */
 

+static void sig_usr1_handler (int s __attribute__((unused))) /* {{{ */
+{
+  config_flush_at_shutdown = 1;
+  sig_common("USR1");
+} /* }}} void sig_usr1_handler */
+
+static void sig_usr2_handler (int s __attribute__((unused))) /* {{{ */
+{
+  config_flush_at_shutdown = 0;
+  sig_common("USR2");
+} /* }}} void sig_usr2_handler */
+

 static void install_signal_handlers(void) /* {{{ */
 {
   /* These structures are static, because `sigaction' behaves weird if the are
 static void install_signal_handlers(void) /* {{{ */
 {
   /* These structures are static, because `sigaction' behaves weird if the are


@@ -219,6 +232,8 @@ static void install_signal_handlers(void) /* {{{ */
   static struct sigaction sa_int;
   static struct sigaction sa_term;
   static struct sigaction sa_pipe;
   static struct sigaction sa_int;
   static struct sigaction sa_term;
   static struct sigaction sa_pipe;

+  static struct sigaction sa_usr1;
+  static struct sigaction sa_usr2;

 
   /* Install signal handlers */
   memset (&sa_int, 0, sizeof (sa_int));
 
   /* Install signal handlers */
   memset (&sa_int, 0, sizeof (sa_int));


@@ -233,6 +248,14 @@ static void install_signal_handlers(void) /* {{{ */
   sa_pipe.sa_handler = SIG_IGN;
   sigaction (SIGPIPE, &sa_pipe, NULL);
 
   sa_pipe.sa_handler = SIG_IGN;
   sigaction (SIGPIPE, &sa_pipe, NULL);
 

+  memset (&sa_pipe, 0, sizeof (sa_usr1));
+  sa_usr1.sa_handler = sig_usr1_handler;
+  sigaction (SIGUSR1, &sa_usr1, NULL);
+
+  memset (&sa_usr2, 0, sizeof (sa_usr2));
+  sa_usr2.sa_handler = sig_usr2_handler;
+  sigaction (SIGUSR2, &sa_usr2, NULL);
+

 } /* }}} void install_signal_handlers */
 
 static int open_pidfile(void) /* {{{ */
 } /* }}} void install_signal_handlers */
 
 static int open_pidfile(void) /* {{{ */


@@ -571,6 +594,7 @@ static void *queue_thread_main (void *args __attribute__((unused))) /* {{{ */
 {
   struct timeval now;
   struct timespec next_flush;
 {
   struct timeval now;
   struct timespec next_flush;

+  int final_flush = 0; /* make sure we only flush once on shutdown */

 
   gettimeofday (&now, NULL);
   next_flush.tv_sec = now.tv_sec + config_flush_interval;
 
   gettimeofday (&now, NULL);
   next_flush.tv_sec = now.tv_sec + config_flush_interval;


@@ -608,8 +632,9 @@ static void *queue_thread_main (void *args __attribute__((unused))) /* {{{ */
     }
 
     /* Now, check if there's something to store away. If not, wait until
     }
 
     /* Now, check if there's something to store away. If not, wait until

-     * something comes in or it's time to do the cache flush. */
-    if (cache_queue_head == NULL)
+     * something comes in or it's time to do the cache flush.  if we are
+     * shutting down, do not wait around.  */
+    if (cache_queue_head == NULL && !do_shutdown)

     {
       status = pthread_cond_timedwait (&cache_cond, &cache_lock, &next_flush);
       if ((status != 0) && (status != ETIMEDOUT))
     {
       status = pthread_cond_timedwait (&cache_cond, &cache_lock, &next_flush);
       if ((status != 0) && (status != ETIMEDOUT))


@@ -619,9 +644,14 @@ static void *queue_thread_main (void *args __attribute__((unused))) /* {{{ */
       }
     }
 
       }
     }
 

-    /* We're about to shut down, so lets flush the entire tree. */
-    if ((do_shutdown != 0) && (cache_queue_head == NULL))
-      flush_old_values (/* max age = */ -1);
+    /* We're about to shut down */
+    if (do_shutdown != 0 && !final_flush++)
+    {
+      if (config_flush_at_shutdown)
+        flush_old_values (-1); /* flush everything */
+      else
+        break;
+    }

 
     /* Check if a value has arrived. This may be NULL if we timed out or there
      * was an interrupt such as a signal. */
 
     /* Check if a value has arrived. This may be NULL if we timed out or there
      * was an interrupt such as a signal. */


@@ -686,14 +716,23 @@ static void *queue_thread_main (void *args __attribute__((unused))) /* {{{ */
 
     pthread_mutex_lock (&cache_lock);
 
 
     pthread_mutex_lock (&cache_lock);
 

-    /* We're about to shut down, so lets flush the entire tree. */
-    if ((do_shutdown != 0) && (cache_queue_head == NULL))
-      flush_old_values (/* max age = */ -1);
+    /* We're about to shut down */
+    if (do_shutdown != 0 && !final_flush++)
+    {
+      if (config_flush_at_shutdown)
+          flush_old_values (-1); /* flush everything */
+      else
+        break;
+    }

   } /* while ((do_shutdown == 0) || (cache_queue_head != NULL)) */
   pthread_mutex_unlock (&cache_lock);
 
   } /* while ((do_shutdown == 0) || (cache_queue_head != NULL)) */
   pthread_mutex_unlock (&cache_lock);
 

-  assert(cache_queue_head == NULL);
-  RRDD_LOG(LOG_INFO, "clean shutdown; all RRDs flushed");
+  if (config_flush_at_shutdown)
+  {
+    assert(cache_queue_head == NULL);
+    RRDD_LOG(LOG_INFO, "clean shutdown; all RRDs flushed");
+  }
+

   journal_done();
 
   return (NULL);
   journal_done();
 
   return (NULL);


@@ -1343,10 +1382,16 @@ static void journal_rotate(void) /* {{{ */
     fclose(old_fh);
 
   if (journal_fh == NULL)
     fclose(old_fh);
 
   if (journal_fh == NULL)

+  {

     RRDD_LOG(LOG_CRIT,
              "JOURNALING DISABLED: Cannot open journal file '%s' : (%s)",
              journal_cur, rrd_strerror(errno));
 
     RRDD_LOG(LOG_CRIT,
              "JOURNALING DISABLED: Cannot open journal file '%s' : (%s)",
              journal_cur, rrd_strerror(errno));
 

+    RRDD_LOG(LOG_ERR,
+             "JOURNALING DISABLED: All values will be flushed at shutdown");
+    config_flush_at_shutdown = 1;
+  }
+

 } /* }}} static void journal_rotate */
 
 static void journal_done(void) /* {{{ */
 } /* }}} static void journal_rotate */
 
 static void journal_done(void) /* {{{ */


@@ -1361,10 +1406,18 @@ static void journal_done(void) /* {{{ */
     journal_fh = NULL;
   }
 
     journal_fh = NULL;
   }
 

-  RRDD_LOG(LOG_INFO, "removing journals");
+  if (config_flush_at_shutdown)
+  {
+    RRDD_LOG(LOG_INFO, "removing journals");
+    unlink(journal_old);
+    unlink(journal_cur);
+  }
+  else
+  {
+    RRDD_LOG(LOG_INFO, "expedited shutdown; "
+             "journals will be used at next startup");
+  }

 
 

-  unlink(journal_old);
-  unlink(journal_cur);

   pthread_mutex_unlock(&journal_lock);
 
 } /* }}} static void journal_done */
   pthread_mutex_unlock(&journal_lock);
 
 } /* }}} static void journal_done */


@@ -1490,7 +1543,9 @@ static void *connection_thread_main (void *args) /* {{{ */
     pollfd.revents = 0;
 
     status = poll (&pollfd, 1, /* timeout = */ 500);
     pollfd.revents = 0;
 
     status = poll (&pollfd, 1, /* timeout = */ 500);

-    if (status == 0) /* timeout */
+    if (do_shutdown)
+      break;
+    else if (status == 0) /* timeout */

       continue;
     else if (status < 0) /* error */
     {
       continue;
     else if (status < 0) /* error */
     {


@@ -1797,11 +1852,11 @@ static void *listen_thread_main (void *args __attribute__((unused))) /* {{{ */
     }
 
     status = poll (pollfds, pollfds_num, /* timeout = */ 1000);
     }
 
     status = poll (pollfds, pollfds_num, /* timeout = */ 1000);

-    if (status == 0)
-    {
-      continue; /* timeout */
-    }
-    else if (status < 0)
+    if (do_shutdown)
+      break;
+    else if (status == 0) /* timeout */
+      continue;
+    else if (status < 0) /* error */

     {
       status = errno;
       if (status != EINTR)
     {
       status = errno;
       if (status != EINTR)


@@ -1965,7 +2020,7 @@ static int read_options (int argc, char **argv) /* {{{ */
   int option;
   int status = 0;
 
   int option;
   int status = 0;
 

-  while ((option = getopt(argc, argv, "gl:f:w:b:z:p:j:h?")) != -1)
+  while ((option = getopt(argc, argv, "gl:f:w:b:z:p:j:h?F")) != -1)

   {
     switch (option)
     {
   {
     switch (option)
     {


@@ -2083,6 +2138,10 @@ static int read_options (int argc, char **argv) /* {{{ */
       }
       break;
 
       }
       break;
 

+      case 'F':
+        config_flush_at_shutdown = 1;
+        break;
+

       case 'j':
       {
         struct stat statbuf;
       case 'j':
       {
         struct stat statbuf;


@@ -2133,6 +2192,7 @@ static int read_options (int argc, char **argv) /* {{{ */
             "  -b <dir>      Base directory to change to.\n"
             "  -g            Do not fork and run in the foreground.\n"
             "  -j <dir>      Directory in which to create the journal files.\n"
             "  -b <dir>      Base directory to change to.\n"
             "  -g            Do not fork and run in the foreground.\n"
             "  -j <dir>      Directory in which to create the journal files.\n"

+            "  -F            Always flush all updates at shutdown\n"

             "\n"
             "For more information and a detailed description of all options "
             "please refer\n"
             "\n"
             "For more information and a detailed description of all options "
             "please refer\n"


@@ -2151,6 +2211,9 @@ static int read_options (int argc, char **argv) /* {{{ */
     fprintf(stderr, "WARNING: write delay (-z) should NOT be larger than"
             " write interval (-w) !\n");
 
     fprintf(stderr, "WARNING: write delay (-z) should NOT be larger than"
             " write interval (-w) !\n");
 

+  if (journal_cur == NULL)
+    config_flush_at_shutdown = 1;
+

   return (status);
 } /* }}} int read_options */
 
   return (status);
 } /* }}} int read_options */