text: /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
  
  /*  Fluent Bit
   *  ==========
   *  Copyright (C) 2015-2022 The Fluent Bit Authors
   *
   *  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
   *
   *      http://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.
   */
  
  #include <fluent-bit/flb_info.h>
  #include <fluent-bit/flb_sds.h>
  #include <fluent-bit/flb_input_plugin.h>
  
  #include "ne.h"
  #include "ne_utils.h"
  
  #include <unistd.h>
  #include <float.h>
  
  /*
   * Diskstats interface references
   * ------------------------------
   * https://www.kernel.org/doc/Documentation/ABI/testing/procfs-diskstats
   * https://www.kernel.org/doc/Documentation/iostats.txt
   *
   * From the documentation, Kernel versions and expected fields:
   *
   *   ==  ===================================
   *    1  major number
   *    2  minor mumber
   *    3  device name
   *    4  reads completed successfully
   *    5  reads merged
   *    6  sectors read
   *    7  time spent reading (ms)
   *    8  writes completed
   *    9  writes merged
   *   10  sectors written
   *   11  time spent writing (ms)
   *   12  I/Os currently in progress
   *   13  time spent doing I/Os (ms)
   *   14  weighted time spent doing I/Os (ms)
   *   ==  ===================================
   *
   *   Kernel 4.18+ appends four more fields for discard
   *   tracking putting the total at 18:
   *
   *   ==  ===================================
   *   15  discards completed successfully
   *   16  discards merged
   *   17  sectors discarded
   *   18  time spent discarding
   *   ==  ===================================
   *
   *   Kernel 5.5+ appends two more fields for flush requests:
   *
   *   ==  =====================================
   *   19  flush requests completed successfully
   *   20  time spent flushing
   *   ==  =====================================
   */
  
  #define KNOWN_FIELDS     17
  #define SECTOR_SIZE      512
  #define IGNORED_DEVICES  "^(ram|loop|fd|(h|s|v|xv)d[a-z]|nvme\\d+n\\d+p)\\d+$"
  
  struct dt_metric {
      void *metric;
      double factor;
  };
  
  static void metric_cache_set(struct flb_ne *ctx, void *metric, double factor, int *offset)
  {
      int id;
      struct dt_metric *m;
      struct dt_metric **cache;
  
      id = *offset;
  
      cache = (struct dt_metric **) ctx->dt_metrics;
      m = (struct dt_metric *) &cache[id];
      m->metric = metric;
      m->factor = factor;
      (*offset)++;
  }
  
  static void metric_cache_update(struct flb_ne *ctx, int id, flb_sds_t device,
                                  flb_sds_t str_val)
  {
      int ret = -1;
      uint64_t ts;
      double val;
      struct dt_metric *m;
      struct dt_metric **cache;
      struct cmt_gauge *g;
      struct cmt_counter *c;
  
      cache = (struct dt_metric **) ctx->dt_metrics;
      m = (struct dt_metric *) &cache[id];
  
      ret = ne_utils_str_to_double(str_val, &val);
      if (ret == -1) {
          flb_plg_error(ctx->ins,
                        "could not represent string value '%s' for metric id '%i', "
                        "device '%s'",
                        str_val, id, device);
          return;
      }
  
      ts = cmt_time_now();
  
      if (m->factor > DBL_EPSILON) {
          val *= m->factor;
      }
  
      if (id == 8) {
          g = (struct cmt_gauge *) m->metric;
          ret = cmt_gauge_set(g, ts, val, 1, (char *[]) {device});
      }
      else {
          c = (struct cmt_counter *) m->metric;
          ret = cmt_counter_set(c, ts, val, 1, (char *[]) {device});
      }
  
      if (ret == -1) {
          flb_plg_error(ctx->ins,
                        "could not update metric id '%i', device '%s'",
                        id, device);
      }
  
  }
  
  /* Setup metrics contexts */
  static int ne_diskstats_configure(struct flb_ne *ctx)
  {
      int offset = 0;
      struct cmt_counter *c;
      struct cmt_gauge *g;
  
      /* Create cache for metrics */
      ctx->dt_metrics = flb_calloc(1, sizeof(struct dt_metric) * KNOWN_FIELDS);
      if (!ctx->dt_metrics) {
          flb_errno();
          return -1;
      }
  
      /* Initialize regex for skipped devices */
      ctx->dt_regex_skip_devices = flb_regex_create(IGNORED_DEVICES);
      if (!ctx->dt_regex_skip_devices) {
          flb_plg_error(ctx->ins,
                        "could not initialize regex pattern for ignored "
                        "devices: '%s'",
                        IGNORED_DEVICES);
          return -1;
      }
  
      /* node_disk_reads_completed_total */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "reads_completed_total",
                             "The total number of reads completed successfully.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, 0, &offset);
  
      /* node_disk_reads_merged_total */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "reads_merged_total",
                             "The total number of reads merged.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, 0, &offset);
  
      /* node_disk_read_bytes_total */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "read_bytes_total",
                             "The total number of bytes read successfully.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, SECTOR_SIZE, &offset);
  
      /* node_disk_read_time_seconds_total */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "read_time_seconds_total",
                             "The total number of seconds spent by all reads.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, .001, &offset);
  
      /* node_disk_writes_completed_total */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "writes_completed_total",
                             "The total number of writes completed successfully.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, 0, &offset);
  
      /* node_disk_writes_merged_total */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "writes_merged_total",
                             "The number of writes merged.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, 0, &offset);
  
      /* node_disk_written_bytes_total */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "written_bytes_total",
                             "The total number of bytes written successfully.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, SECTOR_SIZE, &offset);
  
      /* node_disk_write_time_seconds_total */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "write_time_seconds_total",
                             "This is the total number of seconds spent by all writes.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, .001, &offset);
  
      /* node_disk_io_now */
      g = cmt_gauge_create(ctx->cmt, "node", "disk", "io_now",
                           "The number of I/Os currently in progress.",
                           1, (char *[]) {"device"});
      if (!g) {
          return -1;
      }
      metric_cache_set(ctx, g, 0, &offset);
  
      /* node_disk_io_time_seconds */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "io_time_seconds_total",
                             "Total seconds spent doing I/Os.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, .001, &offset);
  
      /* node_disk_io_time_weighted_seconds */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "io_time_weighted_seconds_total",
                             "The weighted # of seconds spent doing I/Os.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, .001, &offset);
  
      /*
       * Linux Kernel >= 4.18
       * ====================
       */
  
      /* node_disk_discards_completed */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "discards_completed_total",
                             "The total number of discards completed successfully.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, 0, &offset);
  
      /* node_disk_discards_merged */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "discards_merged_total",
                             "The total number of discards merged.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, 0, &offset);
  
      /* node_disk_discarded_sectors */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "discarded_sectors_total",
                             "The total number of sectors discarded successfully.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, 0, &offset);
  
      /* node_disk_discard_time_seconds */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "discard_time_seconds_total",
                             "This is the total number of seconds spent by all discards.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, .001, &offset);
  
      /*
       * Linux Kernel >= 5.5
       * ===================
       */
  
      /* node_disk_flush_requests */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "flush_requests_total",
                             "The total number of flush requests completed successfully",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, 0, &offset);
  
      /* node_disk_flush_requests_time_seconds */
      c = cmt_counter_create(ctx->cmt, "node", "disk", "flush_requests_time_seconds_total",
                             "This is the total number of seconds spent by all flush "
                             "requests.",
                             1, (char *[]) {"device"});
      if (!c) {
          return -1;
      }
      metric_cache_set(ctx, c, .001, &offset);
  
      return 0;
  }
  
  static flb_sds_t get_part_id(struct mk_list *list, int id)
  {
      int i = 0;
      struct mk_list *head;
      struct flb_slist_entry *entry;
  
      mk_list_foreach(head, list) {
          if (i == id) {
              entry = mk_list_entry(head, struct flb_slist_entry, _head);
              return entry->str;
          }
          i++;
      }
      return NULL;
  }
  
  static int skip_device(struct flb_ne *ctx, flb_sds_t device)
  {
      return flb_regex_match(ctx->dt_regex_skip_devices,
                             (unsigned char *) device, flb_sds_len(device));
  }
  
  static int update_stats(struct flb_ne *ctx, struct mk_list *list, int parts)
  {
      int id = 0;
      flb_sds_t device;
      struct mk_list *head;
      struct flb_slist_entry *entry;
  
      /* Get device name: third entry */
      device = get_part_id(list, 2);
      if (!device) {
          flb_plg_error(ctx->ins, "cannot retrieve device name");
          return -1;
      }
  
      /* Check if we should process or skip this device */
      if (skip_device(ctx, device)) {
          flb_plg_debug(ctx->ins, "skip device: %s", device);
          return 0;
      }
  
      mk_list_foreach(head, list) {
          /* Skip: major number, minor number and device name */
          if (id <= 2) {
              id++;
              continue;
          }
          entry = mk_list_entry(head, struct flb_slist_entry, _head);
  
          /* update the metric */
          metric_cache_update(ctx, id - 3, device, entry->str);
          id++;
  
          /* Do not process more than the known fields as of this version */
          if (id - 3 == KNOWN_FIELDS) {
              break;
          }
      }
      return 0;
  }
  
  static int diskstats_update(struct flb_ne *ctx)
  {
      int ret;
      int parts;
      struct mk_list *head;
      struct mk_list list;
      struct mk_list split_list;
      struct flb_slist_entry *line;
  
      mk_list_init(&list);
      mk_list_init(&split_list);
  
      ret = ne_utils_file_read_lines(ctx->path_procfs, "/diskstats", &list);
      if (ret == -1) {
          return -1;
      }
  
      mk_list_foreach(head, &list) {
          line = mk_list_entry(head, struct flb_slist_entry, _head);
  
          mk_list_init(&split_list);
          ret = flb_slist_split_string(&split_list, line->str, ' ', -1);
          if (ret == -1) {
              continue;
          }
          parts = ret;
  
          update_stats(ctx, &split_list, parts);
          flb_slist_destroy(&split_list);
      }
  
      flb_slist_destroy(&list);
      return 0;
  }
  
  int ne_diskstats_init(struct flb_ne *ctx)
  {
      ne_diskstats_configure(ctx);
      return 0;
  }
  
  int ne_diskstats_update(struct flb_ne *ctx)
  {
      diskstats_update(ctx);
      return 0;
  }
  
  int ne_diskstats_exit(struct flb_ne *ctx)
  {
      flb_free(ctx->dt_metrics);
      if (ctx->dt_regex_skip_devices) {
          flb_regex_destroy(ctx->dt_regex_skip_devices);
      }
      return 0;
  }
  