...
- A config function
- An init function
- A read function
- A shutdown function
- A function to register callbacks for all the functions above.
| Code Block |
|---|
#include "collectd.h"
#include "common.h"
#define PLUGIN_NAME "my_plugin"
static _Bool g_enable_option1;
static char g_option2 [DATA_MAX_NAME_LEN];
static int my_config_function(oconfig_item_t *ci) {
int ret = 0;
INFO (PLUGIN_NAME ": %s:%d", __FUNCTION__, __LINE__);
for (int i = 0; i < ci->children_num; i++) {
oconfig_item_t *child = ci->children + i;
if (strcasecmp("Option1", child->key) == 0) {
ret = cf_util_get_boolean(child, & g_enable_option1);
} else if (strcasecmp("Option2 ", child->key) == 0) {
ret = cf_util_get_string_buffer(child, g_option2,
sizeof(g_option2));
}else {
ERROR(PLUGIN_NAME ": Unknown configuration parameter \"%s\".", child->key);
ret = (-1);
}
if (ret != 0) {
INFO (PLUGIN_NAME ": %s:%d ret=%d", __FUNCTION__, __LINE__, ret);
return ret;
}
}
return (0);
}
static int my_read_function(__attribute__((unused)) user_data_t *ud) {
INFO (PLUGIN_NAME ": %s:%d", __FUNCTION__, __LINE__);
/*
* value_list_t vl = VALUE_LIST_INIT;
*
* vl.values = &(value_t){.derive = value}; //NOTE please change this to an appropriate type checkout https://wiki.opnfv.org/display/fastpath/Collectd+101 for more info
*
* vl.values_len = 1;
*
* sstrncpy(vl.plugin, PLUGIN_NAME, sizeof(vl.plugin));
*
* sstrncpy(vl.plugin_instance, plugin_instance, sizeof(vl.plugin_instance));
*
* sstrncpy(vl.type, type, sizeof(vl.type));
*
*
* plugin_dispatch_values(&vl);
*/
return (0);
}
static int my_shutdown_function (void) {
INFO (PLUGIN_NAME ": %s:%d", __FUNCTION__, __LINE__);
return (0);
}
static my_init_function(void) {
INFO(PLUGIN_NAME ": %s:%d", __FUNCTION__, __LINE__);
return (0);
}
void module_register(void) {
plugin_register_init("my_plugin", my_init_function);
plugin_register_complex_config("my_plugin", my_config_function);
plugin_register_complex_read(NULL, "my_plugin", my_read_function, 0, NULL);
plugin_register_shutdown("my_plugin", my_shutdown_function);
}
|
...
- Try to add a double plugin configuration option and read it in with: cf_util_get_double
- Write the configuration parameters to the collectd logfile
Statistics in collectd
Statistics in collectd consist of a value list. A value list includes:
| Value list | Example | comment | |||||
|---|---|---|---|---|---|---|---|
| Values | 99.8999 | percentage | |||||
| Value length | the number of values in the data set. | ||||||
| Time | timestamp at which the value was collected. | 1475837857 | epoch | ||||
| Interval | interval at which to expect a new value. | 10 | interval | ||||
| Host | used to identify the host. | localhost | can be uuid for vm or host… or can give host a name | ||||
| Plugin | used to identify the plugin. | cpu | |||||
| Plugin instance (optional) | used to group a set of values together. For e.g. values belonging to a DPDK interface. | 0 | |||||
| Type | unit used to measure a value. In other words used to refer to a data set. | percent | |||||
| Type instance (optional) | used to distinguish between values that have an identical type. | user | |||||
| meta data | an opaque data structure that enables the passing of additional information about a value list. “Meta data in the global cache can be used to store arbitrary information about an identifier” | ||||||
Notifications in collectd
Notifications in collectd are generic messages containing:
| An associated severity, which can be one of OKAY, WARNING, and FAILURE. | ||||||
| A time. | ||||||
| A Message | ||||||
| A host. | ||||||
| A plugin. | ||||||
| A plugin instance (optional). | ||||||
| A type. | ||||||
| A types instance (optional). | ||||||
| Meta-data. |