htop/DynamicMeter.c

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Add a new DynamicMeter class for runtime Meter extension This commit is based on exploratory work by Sohaib Mohamed. The end goal is two-fold - to support addition of Meters we build via configuration files for both the PCP platform and for scripts ( https://github.com/htop-dev/htop/issues/526 ) Here, we focus on generic code and the PCP support. A new class DynamicMeter is introduced - it uses the special case 'param' field handling that previously was used only by the CPUMeter, such that every runtime-configured Meter is given a unique identifier. Unlike with the CPUMeter this is used internally only. When reading/writing to htoprc instead of CPU(N) - where N is an integer param (CPU number) - we use the string name for each meter. For example, if we have a configuration for a DynamicMeter for some Redis metrics, we might read and write "Dynamic(redis)". This identifier is subsequently matched (back) up to the configuration file so we're able to re-create arbitrary user configurations. The PCP platform configuration file format is fairly simple. We expand configs from several directories, including the users homedir alongside htoprc (below htop/meters/) and also /etc/pcp/htop/meters. The format will be described via a new pcp-htop(5) man page, but its basically ini-style and each Meter has one or more metric expressions associated, as well as specifications for labels, color and so on via a dot separated notation for individual metrics within the Meter. A few initial sample configuration files are provided below ./pcp/meters that give the general idea. The PCP "derived" metric specification - see pmRegisterDerived(3) - is used as the syntax for specifying metrics in PCP DynamicMeters.
2021-06-23 07:44:56 +00:00
/*
htop - DynamicMeter.c
(C) 2021 htop dev team
(C) 2021 Red Hat, Inc. All Rights Reserved.
Released under the GNU GPLv2, see the COPYING file
in the source distribution for its full text.
*/
#include "config.h" // IWYU pragma: keep
#include "DynamicMeter.h"
#include "CRT.h"
#include "Object.h"
#include "Platform.h"
#include "ProcessList.h"
#include "RichString.h"
#include "XUtils.h"
static const int DynamicMeter_attributes[] = {
DYNAMIC_GRAY,
DYNAMIC_DARKGRAY,
DYNAMIC_RED,
DYNAMIC_GREEN,
DYNAMIC_BLUE,
DYNAMIC_CYAN,
DYNAMIC_MAGENTA,
DYNAMIC_YELLOW,
DYNAMIC_WHITE
};
Hashtable* DynamicMeters_new(void) {
return Platform_dynamicMeters();
}
typedef struct {
unsigned int key;
const char* name;
} DynamicIterator;
static void DynamicMeter_compare(ht_key_t key, void* value, void* data) {
const DynamicMeter* meter = (const DynamicMeter*)value;
DynamicIterator* iter = (DynamicIterator*)data;
if (String_eq(iter->name, meter->name))
iter->key = key;
}
unsigned int DynamicMeter_search(const ProcessList* pl, const char* name) {
DynamicIterator iter = { .key = 0, .name = name };
if (pl->dynamicMeters)
Hashtable_foreach(pl->dynamicMeters, DynamicMeter_compare, &iter);
return iter.key;
}
const char* DynamicMeter_lookup(const ProcessList* pl, unsigned int key) {
const DynamicMeter* meter = Hashtable_get(pl->dynamicMeters, key);
return meter ? meter->name : NULL;
}
static void DynamicMeter_init(Meter* meter) {
Platform_dynamicMeterInit(meter);
}
static void DynamicMeter_updateValues(Meter* meter) {
Platform_dynamicMeterUpdateValues(meter);
}
static void DynamicMeter_display(const Object* cast, RichString* out) {
const Meter* meter = (const Meter*)cast;
Platform_dynamicMeterDisplay(meter, out);
}
static void DynamicMeter_getUiName(const Meter* this, char* name, size_t length) {
const ProcessList* pl = this->pl;
const DynamicMeter* meter = Hashtable_get(pl->dynamicMeters, this->param);
if (meter) {
const char* uiName = meter->caption ? meter->caption : meter->name;
xSnprintf(name, length, "%s", uiName);
}
}
const MeterClass DynamicMeter_class = {
.super = {
.extends = Class(Meter),
.delete = Meter_delete,
.display = DynamicMeter_display
},
.init = DynamicMeter_init,
.updateValues = DynamicMeter_updateValues,
.getUiName = DynamicMeter_getUiName,
.defaultMode = TEXT_METERMODE,
.maxItems = 0,
.total = 100.0,
.attributes = DynamicMeter_attributes,
.name = "Dynamic",
.uiName = "Dynamic",
.caption = "",
};