Function RecReadStatsFile

src/records/P_RecCore.cc:272–325

------------------------------------------------------------------------- RecReadStatsFile -------------------------------------------------------------------------

// RecReadStatsFile
//-------------------------------------------------------------------------
RecErrT
RecReadStatsFile()
{
  RecRecord     *r;
  RecMessage    *m;
  RecMessageItr  itr;
  RecPersistT    persist_type = RECP_NULL;
  ats_scoped_str snap_fpath(RecConfigReadPersistentStatsPath());

  // lock our hash table
  ink_rwlock_wrlock(&g_records_rwlock);

  CheckSnapFileVersion(snap_fpath);

  if ((m = RecMessageReadFromDisk(snap_fpath)) != nullptr) {
    if (RecMessageUnmarshalFirst(m, &itr, &r) != REC_ERR_FAIL) {
      do {
        if ((r->name == nullptr) || (!strlen(r->name))) {
          continue;
        }

        // If we don't have a persistence type for this record, it means that it is not a stat, or it is
        // not registered yet. Either way, it's ok to just set the persisted value and keep going.
        if (RecGetRecordPersistenceType(r->name, &persist_type, false /* lock */) != REC_ERR_OKAY) {
          RecDebug(DL_Debug, "restoring value for persisted stat '%s'", r->name);
          RecSetRecord(r->rec_type, r->name, r->data_type, &(r->data), &(r->stat_meta.data_raw), REC_SOURCE_EXPLICIT, false);
          continue;
        }

        if (!REC_TYPE_IS_STAT(r->rec_type)) {
          // This should not happen, but be defensive against records changing their type ..
          RecLog(DL_Warning, "skipping restore of non-stat record '%s'", r->name);
          continue;
        }

        // Check whether the persistence type was changed by a new software version. If the record is
        // already registered with an updated persistence type, then we don't want to set it. We should
        // keep the registered value.
        if (persist_type == RECP_NON_PERSISTENT) {
          RecDebug(DL_Debug, "preserving current value of formerly persistent stat '%s'", r->name);
          continue;
        }

        RecDebug(DL_Debug, "restoring value for persisted stat '%s'", r->name);
        RecSetRecord(r->rec_type, r->name, r->data_type, &(r->data), &(r->stat_meta.data_raw), REC_SOURCE_EXPLICIT, false);
      } while (RecMessageUnmarshalNext(m, &itr, &r) != REC_ERR_FAIL);
    }
  }

  ink_rwlock_unlock(&g_records_rwlock);
  ats_free(m);

  return REC_ERR_OKAY;
}

//-------------------------------------------------------------------------
// RecSyncStatsFile