src/rrd_graph.[ch]: Implemented the ":daemon=..." option for "DEF:" commands.

Rather than calling "FLUSH" for each RRD file needed for drawing a
graph and then accessing the file directly, use the "FLUSH" command to
receive the data required for drawing a graph.

The daemon can now be specified in one of three ways:

  * A new option has been added to the "DEF" option. If the "DEF" command
    includes the option "daemon=...", then the given daemon is used for
    accessing that file only. This option takes precedence over all
    other options. The value given follows the same syntax as other ways
    to specify a daemon address, thouh colons need to be escaped from
    rrdgraph(1).

    Example:
      'DEF:v1=path/to/example.rrd:value:AVERAGE:daemon=collect1.octo.cx'

  * The "--daemon" option can be given to the overall "rrdtool graph"
    command. When given, this address is used for all file accesses
    except those which explicitely contain a "daemon=..." option.

  * If the "RRDCACHED_ADDRESS" environment variable is set, it's value
    is used as the daemon address. This is the lowest priority option
    and only used if no other option is given.

One nice detail is that with ":daemon=...", the cache address can be
specified for each "DEF:" definition. It is therefore possible to graph
values stored on several servers in one graph – even if several RRD
files have the same name.

diff --git a/doc/rrdgraph_data.pod b/doc/rrdgraph_data.pod
index d5ceddb..57b9d0a 100644 (file)
--- a/doc/rrdgraph_data.pod
+++ b/doc/rrdgraph_data.pod
@@ -4,7 +4,7 @@ rrdgraph_data - preparing data for graphing in rrdtool graph
 
 =head1 SYNOPSIS
 
-B<DEF:>I<E<lt>vnameE<gt>>=I<E<lt>rrdfileE<gt>>:I<E<lt>ds-nameE<gt>>:I<E<lt>CFE<gt>>[:step=I<E<lt>stepE<gt>>][:start=I<E<lt>timeE<gt>>][:end=I<E<lt>timeE<gt>>][:reduce=I<E<lt>B<CF>E<gt>>]
+B<DEF:>I<E<lt>vnameE<gt>>=I<E<lt>rrdfileE<gt>>:I<E<lt>ds-nameE<gt>>:I<E<lt>CFE<gt>>[:step=I<E<lt>stepE<gt>>][:start=I<E<lt>timeE<gt>>][:end=I<E<lt>timeE<gt>>][:reduce=I<E<lt>B<CF>E<gt>>][:daemon=I<E<lt>addressE<gt>>]
 
 B<VDEF>:I<vname>=I<RPN expression>
 
@@ -28,7 +28,7 @@ mixed case names for variables since operators will always be in uppercase.
 
 =head1 DEF
 
-B<DEF:>I<E<lt>vnameE<gt>>=I<E<lt>rrdfileE<gt>>:I<E<lt>ds-nameE<gt>>:I<E<lt>CFE<gt>>[:step=I<E<lt>stepE<gt>>][:start=I<E<lt>timeE<gt>>][:end=I<E<lt>timeE<gt>>][:reduce=I<E<lt>B<CF>E<gt>>]
+B<DEF:>I<E<lt>vnameE<gt>>=I<E<lt>rrdfileE<gt>>:I<E<lt>ds-nameE<gt>>:I<E<lt>CFE<gt>>[:step=I<E<lt>stepE<gt>>][:start=I<E<lt>timeE<gt>>][:end=I<E<lt>timeE<gt>>][:reduce=I<E<lt>B<CF>E<gt>>][:daemon=I<E<lt>addressE<gt>>]
 
 This command fetches data from an B<RRD> file.  The virtual name
 I<vname> can then be used throughout the rest of the script. By
@@ -54,12 +54,20 @@ B<DEF> itself will be used to reduce the data density. This behavior can
 be changed using C<:reduce=I<E<lt>B<CF>E<gt>>>.  This optional parameter
 specifies the B<CF> to use during the data reduction phase.
 
+It is possible to request single data sources from a specific I<RRDCacheD>, see
+L<rrdcached(1)>, using the C<:daemon=I<E<lt>addressE<gt>>> parameter. The
+value given to this parameter follows the same syntax as other means to specify
+the address of the caching daemon. It is described in detail in the
+L<rrdcached(1)> manual page. Beware, however, that colons (in IPv6 addresses
+and as a port separator, for example) need to be escaped using a backslash.
+
 Example:
 
         DEF:ds0=router.rrd:ds0:AVERAGE
         DEF:ds0weekly=router.rrd:ds0:AVERAGE:step=7200
         DEF:ds0weekly=router.rrd:ds0:AVERAGE:start=end-1h
         DEF:ds0weekly=router.rrd:ds0:AVERAGE:start=11\:00:end=start+1h
+        DEF:ds0weekly=router.rrd:ds0:AVERAGE:daemon=collect1.example.com
 
 =head1 VDEF
 

diff --git a/src/rrd_graph.c b/src/rrd_graph.c
index 9e23a4a..872dd44 100644 (file)
--- a/src/rrd_graph.c
+++ b/src/rrd_graph.c
@@ -845,46 +845,48 @@ int data_fetch(
         }
         if (!skip) {
             unsigned long ft_step = im->gdes[i].step;   /* ft_step will record what we got from fetch */
+            const char *daemon;
+            int status;
 
-            /* Flush the file if
-             * - a connection to the daemon has been established
-             * - this is the first occurrence of that RRD file
-             */
-            if (rrdc_is_connected(im->daemon_addr))
+            if (im->gdes[i].daemon[0] != 0)
+                daemon = im->gdes[i].daemon;
+            else
+                daemon = im->daemon_addr;
+
+            /* "daemon" may be NULL. ENV_RRDCACHED_ADDRESS is evaluated in that
+             * case. If "daemon" holds the same value as in the previous
+             * iteration, no actual new connection is established - the
+             * existing connection is re-used. */
+            rrdc_connect (daemon);
+
+            /* If connecting was successfull, use the daemon to query the data.
+             * If there is no connection, for example because no daemon address
+             * was specified, (try to) use the local file directly. */
+            if (rrdc_is_connected (daemon))
             {
-                int status;
-
-                status = 0;
-                for (ii = 0; ii < i; ii++)
-                {
-                    if (strcmp (im->gdes[i].rrd, im->gdes[ii].rrd) == 0)
-                    {
-                        status = 1;
-                        break;
-                    }
-                }
-
-                if (status == 0)
-                {
-                    status = rrdc_flush (im->gdes[i].rrd);
-                    if (status != 0)
-                    {
-                        rrd_set_error ("rrdc_flush (%s) failed with status %i.",
-                                im->gdes[i].rrd, status);
-                        return (-1);
-                    }
+                status = rrdc_fetch (im->gdes[i].rrd,
+                        cf_to_string (im->gdes[i].cf),
+                        &im->gdes[i].start,
+                        &im->gdes[i].end,
+                        &ft_step,
+                        &im->gdes[i].ds_cnt,
+                        &im->gdes[i].ds_namv,
+                        &im->gdes[i].data);
+                if (status != 0)
+                    return (status);
+            }
+            else
+            {
+                if ((rrd_fetch_fn(im->gdes[i].rrd,
+                                im->gdes[i].cf,
+                                &im->gdes[i].start,
+                                &im->gdes[i].end,
+                                &ft_step,
+                                &im->gdes[i].ds_cnt,
+                                &im->gdes[i].ds_namv,
+                                &im->gdes[i].data)) == -1) {
+                    return -1;
                 }
-            } /* if (rrdc_is_connected()) */
-
-            if ((rrd_fetch_fn(im->gdes[i].rrd,
-                              im->gdes[i].cf,
-                              &im->gdes[i].start,
-                              &im->gdes[i].end,
-                              &ft_step,
-                              &im->gdes[i].ds_cnt,
-                              &im->gdes[i].ds_namv,
-                              &im->gdes[i].data)) == -1) {
-                return -1;
             }
             im->gdes[i].data_first = 1;
 
@@ -3799,6 +3801,7 @@ int gdes_alloc(
     im->gdes[im->gdes_c - 1].cf = CF_AVERAGE;
     im->gdes[im->gdes_c - 1].yrule = DNAN;
     im->gdes[im->gdes_c - 1].xrule = 0;
+    im->gdes[im->gdes_c - 1].daemon[0] = 0;
     return 0;
 }
 
@@ -4636,11 +4639,6 @@ void rrd_graph_options(
         }
     } /* while (1) */
 
-    {   /* try to connect to rrdcached */
-        int status = rrdc_connect(im->daemon_addr);
-        if (status != 0) return;
-    }
-
     pango_cairo_context_set_font_options(pango_layout_get_context(im->layout), im->font_options);
     pango_layout_context_changed(im->layout);
 

diff --git a/src/rrd_graph.h b/src/rrd_graph.h
index 8e28f63..b811926 100644 (file)
--- a/src/rrd_graph.h
+++ b/src/rrd_graph.h
@@ -158,6 +158,7 @@ typedef struct graph_desc_t {
     char      rrd[1024];    /* name of the rrd_file containing data */
     char      ds_nam[DS_NAM_SIZE];  /* data source name */
     long      ds;       /* data source number */
+    char      daemon[256];
     enum cf_en cf;      /* consolidation function */
     enum cf_en cf_reduce;   /* consolidation function for reduce_data() */
     struct gfx_color_t col; /* graph color */

diff --git a/src/rrd_graph_helper.c b/src/rrd_graph_helper.c
index 88d4d9a..60ef0d0 100644 (file)
--- a/src/rrd_graph_helper.c
+++ b/src/rrd_graph_helper.c
@@ -962,6 +962,11 @@ int rrd_parse_def(
                 return 1;
             }
             dprintf("- done parsing:  '%s'\n", &line[*eaten]);
+        } else if (!strcmp("daemon", command)) {
+            i = scan_for_col(&line[*eaten],
+                    sizeof (gdp->daemon), gdp->daemon);
+            (*eaten) += i;
+            dprintf("- using daemon '%s'\n", gdp->daemon);
         } else {
             rrd_set_error("Parse error in '%s'", line);
             return 1;