=back
+=head2 Plugin C<tail>
+
+The C<tail plugin> plugins follows logfiles, just like L<tail(1)> does, parses
+each line and dispatches found values. What is matched can be configured by the
+user using (extended) regular expressions, as described in L<regex(7)>.
+
+ <Plugin "tail">
+ <File "/var/log/exim4/mainlog">
+ Instance "exim"
+ <Match>
+ Regex "S=([1-9][0-9]*)"
+ DSType "CounterAdd"
+ Type "ipt_bytes"
+ Instance "total"
+ </Match>
+ <Match>
+ Regex "\\<R=local_user\\>"
+ DSType "CounterInc"
+ Type "email_count"
+ Instance "local_user"
+ </Match>
+ </File>
+ </Plugin>
+
+The config consists of one or more B<File> blocks, each of which configures one
+logfile to parse. Within each B<File> block, there are one or more B<Match>
+blocks, which configure a regular expression to search for.
+
+The B<Instance> option in the B<File> block may be used to set the plugin
+instance. So in the above example the plugin name C<tail-foo> would be used.
+This plugin instance is for all B<Match> blocks that B<follow> it, until the
+next B<Instance> option. This way you can extract several plugin instances from
+one logfile, handy when parsing syslog and the like.
+
+Each B<Match> block has the following options to describe how the match should
+be performed:
+
+=over 4
+
+=item B<Regex> I<regex>
+
+Sets the regular expression to use for matching against a line. The first
+subexpression has to match something that can be turned into a number by
+L<strtoll(3)> or L<strtod(3)>, depending on the value of C<CounterAdd>, see
+below. Because B<extended> regular expressions are used, you do not need to use
+backslashes for subexpressions! If in doubt, please consult L<regex(7)>. Due to
+collectd's config parsing you need to escape backslashes, though. So if you
+want to match literal parentheses you need to do the following:
+
+ Regex "SPAM \\(Score: (-?[0-9]+\\.[0-9]+)\\)"
+
+=item B<DSType> I<Type>
+
+Sets how the values are cumulated. I<Type> is one of:
+
+=over 4
+
+=item B<GaugeAverage>
+
+Calculate the average.
+
+=item B<GaugeMin>
+
+Use the smallest number only.
+
+=item B<GaugeMax>
+
+Use the greatest number only.
+
+=item B<GaugeLast>
+
+Use the last number found.
+
+=item B<CounterSet>
+
+The matched number is a counter. Simply sets the internal counter to this
+value.
+
+=item B<CounterAdd>
+
+Add the matched value to the internal counter.
+
+=item B<CounterInc>
+
+Increase the internal counter by one. This B<DSType> is the only one that does
+not use the matched subexpression, but simply counts the number of matched
+lines. Thus, you may use a regular expression without submatch in this case.
+
+=back
+
+As you'd expect the B<Gauge*> types interpret the submatch as a floating point
+number, using L<strtod(3)>. The B<CounterSet> and B<CounterAdd> interpret the
+submatch as an integer using L<strtoll(3)>. B<CounterInc> does not use the
+submatch at all and it may be omitted in this case.
+
+=item B<Type> I<Type>
+
+Sets the type used to dispatch this value. Detailed information about types and
+their configuration can be found in L<types.db(5)>.
+
+=item B<Instance> I<TypeInstance>
+
+This optional setting sets the type instance to use.
+
+=back
+
=head2 Plugin C<tcpconns>
The C<tcpconns plugin> counts the number of currently established TCP
--- /dev/null
+/**
+ * collectd - src/tail.c
+ * Copyright (C) 2008 Florian octo Forster
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; only version 2 of the License is applicable.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Authors:
+ * Florian octo Forster <octo at verplant.org>
+ **/
+
+#include "collectd.h"
+#include "common.h"
+#include "plugin.h"
+#include "utils_tail_match.h"
+
+/*
+ * <Plugin tail>
+ * <File "/var/log/exim4/mainlog">
+ * Instance "exim"
+ * <Match>
+ * Regex "S=([1-9][0-9]*)"
+ * DSType "CouterAdd"
+ * Type "ipt_bytes"
+ * Instance "total"
+ * </Match>
+ * </File>
+ * </Plugin>
+ */
+
+struct ctail_config_match_s
+{
+ char *regex;
+ int flags;
+ char *type;
+ char *type_instance;
+};
+typedef struct ctail_config_match_s ctail_config_match_t;
+
+cu_tail_match_t **tail_match_list = NULL;
+size_t tail_match_list_num = 0;
+
+static int ctail_config_add_string (const char *name, char **dest, oconfig_item_t *ci)
+{
+ if ((ci->values_num != 1) || (ci->values[0].type != OCONFIG_TYPE_STRING))
+ {
+ WARNING ("tail plugin: `%s' needs exactly one string argument.", name);
+ return (-1);
+ }
+
+ sfree (*dest);
+ *dest = strdup (ci->values[0].value.string);
+ if (*dest == NULL)
+ return (-1);
+
+ return (0);
+} /* int ctail_config_add_string */
+
+static int ctail_config_add_match_dstype (ctail_config_match_t *cm,
+ oconfig_item_t *ci)
+{
+ if ((ci->values_num != 1) || (ci->values[0].type != OCONFIG_TYPE_STRING))
+ {
+ WARNING ("tail plugin: `DSType' needs exactly one string argument.");
+ return (-1);
+ }
+
+ if (strncasecmp ("Gauge", ci->values[0].value.string, strlen ("Gauge")) == 0)
+ {
+ cm->flags = UTILS_MATCH_DS_TYPE_GAUGE;
+ if (strcasecmp ("GaugeAverage", ci->values[0].value.string) == 0)
+ cm->flags |= UTILS_MATCH_CF_GAUGE_AVERAGE;
+ else if (strcasecmp ("GaugeMin", ci->values[0].value.string) == 0)
+ cm->flags |= UTILS_MATCH_CF_GAUGE_MIN;
+ else if (strcasecmp ("GaugeMax", ci->values[0].value.string) == 0)
+ cm->flags |= UTILS_MATCH_CF_GAUGE_MAX;
+ else if (strcasecmp ("GaugeLast", ci->values[0].value.string) == 0)
+ cm->flags |= UTILS_MATCH_CF_GAUGE_LAST;
+ else
+ cm->flags = 0;
+ }
+ else if (strncasecmp ("Counter", ci->values[0].value.string, strlen ("Counter")) == 0)
+ {
+ cm->flags = UTILS_MATCH_DS_TYPE_COUNTER;
+ if (strcasecmp ("CouterSet", ci->values[0].value.string) == 0)
+ cm->flags |= UTILS_MATCH_CF_COUNTER_SET;
+ else if (strcasecmp ("CouterAdd", ci->values[0].value.string) == 0)
+ cm->flags |= UTILS_MATCH_CF_COUNTER_ADD;
+ else if (strcasecmp ("CouterInc", ci->values[0].value.string) == 0)
+ cm->flags |= UTILS_MATCH_CF_COUNTER_INC;
+ else
+ cm->flags = 0;
+ }
+ else
+ {
+ cm->flags = 0;
+ }
+
+ if (cm->flags == 0)
+ {
+ WARNING ("tail plugin: `%s' is not a valid argument to `DSType'.",
+ ci->values[0].value.string);
+ return (-1);
+ }
+
+ return (0);
+} /* int ctail_config_add_match_dstype */
+
+static int ctail_config_add_match (cu_tail_match_t *tm,
+ const char *plugin_instance, oconfig_item_t *ci)
+{
+ ctail_config_match_t cm;
+ int status;
+ int i;
+
+ memset (&cm, '\0', sizeof (cm));
+
+ if (ci->values_num != 0)
+ {
+ WARNING ("tail plugin: Ignoring arguments for the `Match' block.");
+ }
+
+ status = 0;
+ for (i = 0; i < ci->children_num; i++)
+ {
+ oconfig_item_t *option = ci->children + i;
+
+ if (strcasecmp ("Regex", option->key) == 0)
+ status = ctail_config_add_string ("Regex", &cm.regex, option);
+ else if (strcasecmp ("DSType", option->key) == 0)
+ status = ctail_config_add_match_dstype (&cm, option);
+ else if (strcasecmp ("Type", option->key) == 0)
+ status = ctail_config_add_string ("Type", &cm.type, option);
+ else if (strcasecmp ("Instance", option->key) == 0)
+ status = ctail_config_add_string ("Instance", &cm.type_instance, option);
+ else
+ {
+ WARNING ("tail plugin: Option `%s' not allowed here.", option->key);
+ status = -1;
+ }
+
+ if (status != 0)
+ break;
+ } /* for (i = 0; i < ci->children_num; i++) */
+
+ while (status == 0)
+ {
+ if (cm.regex == NULL)
+ {
+ WARNING ("tail plugin: `Regex' missing in `Match' block.");
+ status = -1;
+ break;
+ }
+
+ if (cm.type == NULL)
+ {
+ WARNING ("tail plugin: `Type' missing in `Match' block.");
+ status = -1;
+ break;
+ }
+
+ if (cm.flags == 0)
+ {
+ WARNING ("tail plugin: `DSType' missing in `Match' block.");
+ status = -1;
+ break;
+ }
+
+ break;
+ } /* while (status == 0) */
+
+ if (status == 0)
+ {
+ status = tail_match_add_match_simple (tm, cm.regex, cm.flags,
+ "tail", plugin_instance, cm.type, cm.type_instance);
+
+ if (status != 0)
+ {
+ ERROR ("tail plugin: tail_match_add_match_simple failed.");
+ }
+ }
+
+ sfree (cm.regex);
+ sfree (cm.type);
+ sfree (cm.type_instance);
+
+ return (status);
+} /* int ctail_config_add_match */
+
+static int ctail_config_add_file (oconfig_item_t *ci)
+{
+ cu_tail_match_t *tm;
+ char *plugin_instance = NULL;
+ int num_matches = 0;
+ int status;
+ int i;
+
+ if ((ci->values_num != 1) || (ci->values[0].type != OCONFIG_TYPE_STRING))
+ {
+ WARNING ("tail plugin: `File' needs exactly one string argument.");
+ return (-1);
+ }
+
+ tm = tail_match_create (ci->values[0].value.string);
+ if (tm == NULL)
+ {
+ ERROR ("tail plugin: tail_match_create (%s) failed.",
+ ci->values[0].value.string);
+ return (-1);
+ }
+
+ status = 0;
+ for (i = 0; i < ci->children_num; i++)
+ {
+ oconfig_item_t *option = ci->children + i;
+
+ if (strcasecmp ("Match", option->key) == 0)
+ {
+ status = ctail_config_add_match (tm, plugin_instance, option);
+ if (status == 0)
+ num_matches++;
+ /* Be mild with failed matches.. */
+ status = 0;
+ }
+ else if (strcasecmp ("Instance", option->key) == 0)
+ status = ctail_config_add_string ("Instance", &plugin_instance, option);
+ else
+ {
+ WARNING ("tail plugin: Option `%s' not allowed here.", option->key);
+ status = -1;
+ }
+
+ if (status != 0)
+ break;
+ } /* for (i = 0; i < ci->children_num; i++) */
+
+ if (num_matches == 0)
+ {
+ ERROR ("tail plugin: No (valid) matches found for file `%s'.",
+ ci->values[0].value.string);
+ tail_match_destroy (tm);
+ return (-1);
+ }
+ else
+ {
+ cu_tail_match_t **temp;
+
+ temp = (cu_tail_match_t **) realloc (tail_match_list,
+ sizeof (cu_tail_match_t *) * (tail_match_list_num + 1));
+ if (temp == NULL)
+ {
+ ERROR ("tail plugin: realloc failed.");
+ tail_match_destroy (tm);
+ return (-1);
+ }
+
+ tail_match_list = temp;
+ tail_match_list[tail_match_list_num] = tm;
+ tail_match_list_num++;
+ }
+
+ return (0);
+} /* int ctail_config_add_file */
+
+static int ctail_config (oconfig_item_t *ci)
+{
+ int i;
+
+ for (i = 0; i < ci->children_num; i++)
+ {
+ oconfig_item_t *option = ci->children + i;
+
+ if (strcasecmp ("File", option->key) == 0)
+ ctail_config_add_file (option);
+ else
+ {
+ WARNING ("tail plugin: Option `%s' not allowed here.", option->key);
+ }
+ } /* for (i = 0; i < ci->children_num; i++) */
+
+ return (0);
+} /* int ctail_config */
+
+static int ctail_init (void)
+{
+ if (tail_match_list_num == 0)
+ {
+ WARNING ("tail plugin: File list is empty. Returning an error.");
+ return (-1);
+ }
+
+ return (0);
+} /* int ctail_init */
+
+static int ctail_read (void)
+{
+ int success = 0;
+ int i;
+
+ for (i = 0; i < tail_match_list_num; i++)
+ {
+ int status;
+
+ status = tail_match_read (tail_match_list[i]);
+ if (status != 0)
+ {
+ ERROR ("tail plugin: tail_match_read[%i] failed.", i);
+ }
+ else
+ {
+ success++;
+ }
+ }
+
+ if (success == 0)
+ return (-1);
+ return (0);
+} /* int ctail_read */
+
+static int ctail_shutdown (void)
+{
+ int i;
+
+ for (i = 0; i < tail_match_list_num; i++)
+ {
+ tail_match_destroy (tail_match_list[i]);
+ tail_match_list[i] = NULL;
+ }
+ sfree (tail_match_list);
+ tail_match_list_num = 0;
+
+ return (0);
+} /* int ctail_shutdown */
+
+void module_register (void)
+{
+ plugin_register_complex_config ("tail", ctail_config);
+ plugin_register_init ("tail", ctail_init);
+ plugin_register_read ("tail", ctail_read);
+ plugin_register_shutdown ("tail", ctail_shutdown);
+} /* void module_register */
+
+/* vim: set sw=2 sts=2 ts=8 : */
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