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/*
* Copyright 2018 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define _POSIX_C_SOURCE 200809L
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "scrape.h"
#include "util.h"
// size of input buffer for paths and lines
#define BUF_SIZE 256
// assumed constant size of disk sector in /proc/diskstats
#define SECTOR_SIZE 512
static void *diskstats_init(int argc, char *argv[]);
static void diskstats_collect(scrape_req *req, void *ctx);
const struct collector diskstats_collector = {
.name = "diskstats",
.collect = diskstats_collect,
.init = diskstats_init,
.has_args = true,
};
struct diskstats_context {
struct slist *include;
struct slist *exclude;
bool filter_unused;
};
static void *diskstats_init(int argc, char *argv[]) {
struct diskstats_context *ctx = must_malloc(sizeof *ctx);
ctx->include = 0;
ctx->exclude = 0;
ctx->filter_unused = true;
for (int arg = 0; arg < argc; arg++) {
if (strncmp(argv[arg], "include=", 8) == 0) {
ctx->include = slist_split(&argv[arg][8], ",");
} else if (strncmp(argv[arg], "exclude=", 8) == 0) {
ctx->exclude = slist_split(&argv[arg][8], ",");
} else if (strcmp(argv[arg], "keep-unused") == 0) {
ctx->filter_unused = false;
} else {
fprintf(stderr, "unknown argument for diskstats collector: %s", argv[arg]);
return 0;
}
}
return ctx;
}
static const struct {
const char *metric;
double factor;
} columns[] = {
{ .metric = "node_disk_reads_completed_total", .factor = 1.0 },
{ .metric = "node_disk_reads_merged_total", .factor = 1.0 },
{ .metric = "node_disk_read_bytes_total", .factor = SECTOR_SIZE },
{ .metric = "node_disk_read_time_seconds_total", .factor = 0.001 },
{ .metric = "node_disk_writes_completed_total", .factor = 1.0 },
{ .metric = "node_disk_writes_merged_total", .factor = 1.0 },
{ .metric = "node_disk_written_bytes_total", .factor = SECTOR_SIZE },
{ .metric = "node_disk_write_time_seconds_total", .factor = 0.001 },
{ .metric = "node_disk_io_now", .factor = 1.0 },
{ .metric = "node_disk_io_time_seconds_total", .factor = 0.001 },
{ .metric = "node_disk_io_time_weighted_seconds_total", .factor = 0.001 },
{ .metric = "node_disk_discards_completed_total", .factor = 1.0 },
{ .metric = "node_disk_discards_merged_total", .factor = 1.0 },
{ .metric = "node_disk_discarded_sectors_total", .factor = 1.0 },
{ .metric = "node_disk_discard_time_seconds_total", .factor = 0.001 },
};
#define NCOLUMNS (sizeof columns / sizeof *columns)
static void diskstats_collect(scrape_req *req, void *ctx_ptr) {
struct diskstats_context *ctx = ctx_ptr;
// buffers
struct label labels[] = {
{ .key = "device", .value = 0 }, // value filled by code
LABEL_END,
};
char buf[BUF_SIZE];
FILE *f;
// emit metrics for all known columns of /proc/diskstats for included devices
f = fopen(PATH("/proc/diskstats"), "r");
if (!f)
return;
while (fgets_line(buf, sizeof buf, f)) {
char *p;
// skip first two columns (device node numbers)
strtok_r(buf, " ", &p);
strtok_r(0, " ", &p);
// extract device name
char *dev = strtok_r(0, " ", &p);
if (!dev || *dev == '\0')
continue;
labels[0].value = dev;
// filter
if (ctx->include) {
if (!slist_matches(ctx->include, dev))
continue;
} else if (ctx->exclude) {
if (slist_matches(ctx->exclude, dev))
continue;
}
if (ctx->filter_unused) {
char *tail = dev + strlen(dev) + 1;
if (tail < buf + sizeof buf && strspn(tail, " 0\n") == strlen(tail))
continue; // only spaces, zeros and newlines: unused device
}
// emit metrics while known columns last
for (size_t c = 0; c < NCOLUMNS; c++) {
char *v = strtok_r(0, " \n", &p);
if (!v || *v == '\0')
break;
char *end;
double d = strtod(v, &end);
if (*end != '\0')
continue;
scrape_write(req, columns[c].metric, labels, d * columns[c].factor);
}
}
fclose(f);
}
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