using dataclasses

ioztat

@@ -29,13 +29,15 @@
 
 import argparse
 import copy
+import dataclasses
 import math
 import os
 import re
 import shutil
 import signal
 import sys
 import time
+import typing
 
 PROGRAM_VERSION = '2.0.2-dev'
 
@@ -93,6 +95,15 @@ if sys.platform.startswith("linux"):
         @staticmethod
         def parse_dataset(file):
             """Parse a single ZFS objset file"""
+            # header format is defined in
+            #
+            # https://github.com/openzfs/zfs/blob/9681de4657686d0ed19ca18d578513e74395f00f/module/os/linux/spl/spl-kstat.c#L53
+            #
+            # seq_printf(f, "%d %d 0x%02x %d %d %lld %lld\n",
+            # ksp->ks_kid, ksp->ks_type, ksp->ks_flags,
+            # ksp->ks_ndata, (int)ksp->ks_data_size,
+            # ksp->ks_crtime, ksp->ks_snaptime);
+            #
             # Shortened example of these files:
             #############################################
             # 31 1 0x01 7 2160 6165792836 1634992995579
@@ -196,18 +207,23 @@ else:
 class Dataset:
     """
     ZFS dataset statistics over a timespan in seconds
+
+    The Dataset fields are "documented" here:
+    https://github.com/openzfs/zfs/blob/9681de4657686d0ed19ca18d578513e74395f00f/module/zfs/dataset_kstats.c#L32
+
     """
-    name = ''
-    reads = 0
-    nread = 0
-    writes = 0
-    nwritten = 0
-    nunlinks = 0
-    nunlinked = 0
-    timespan = 0
-
-    def __init__(self, name=''):
+    __slots__ = ("name", "reads", "nread", "writes", "nwritten", "nunlinks", "nunlinked", "timespan")
+
+    def __init__(self, name='', reads=0, nread=0, writes=0, nwritten=0, nunlinks=0, nunlinked=0, timespan=0):
         self.name = name
+        self.reads = reads
+        self.nread = nread
+        self.writes = writes
+        self.nwritten = nwritten
+        self.nunlinks = nunlinks
+        self.nunlinked = nunlinked
+        self.timespan = timespan
+
 
     @classmethod
     def from_dict(cls, data):
@@ -221,6 +237,13 @@ class Dataset:
         d.timespan = int(data['timestamp']) / 1e9
         return d
 
+
+
+#    @property
+#    def name(self):
+#        return self.name
+
+
     @property
     def rareq_sz(self):
         return self.nread / self.reads if self.reads else 0
@@ -246,7 +269,7 @@ class Dataset:
         Return a copy of Dataset with values normalized to per-second rates
         """
         if self.timespan:
-            d = copy.copy(self)
+            d = Dataset(self.name)
             d.reads /= self.timespan
             d.nread /= self.timespan
             d.writes /= self.timespan
@@ -261,31 +284,32 @@ class Dataset:
         """
         Return a new Dataset with this one's values subtracted from other
         """
-        d = copy.copy(self)
-        d.reads -= other.reads
-        d.nread -= other.nread
-        d.writes -= other.writes
-        d.nwritten -= other.nwritten
-        d.nunlinks -= other.nunlinks
-        d.nunlinked -= other.nunlinked
-        d.timespan -= other.timespan
+        d = Dataset(self.name)
+        d.reads = self.reads - other.reads
+        d.nread = self.nread - other.nread
+        d.writes = self.writes - other.writes
+        d.nwritten = self.nwritten - other.nwritten
+        d.nunlinks = self.nunlinks - other.nunlinks
+        d.nunlinked = self.nunlinked - other.nunlinked
+        d.timespan = self.timespan - other.timespan
         return d
 
+
     def __add__(self, other):
         """
         Return a new Dataset with this one's values added to other
 
         Note timespan is set to the maximum of the two values instead of being
         added.
         """
-        d = copy.copy(self)
-        d.reads += other.reads
-        d.nread += other.nread
-        d.writes += other.writes
-        d.nwritten += other.nwritten
-        d.nunlinks += other.nunlinks
-        d.nunlinked += other.nunlinked
-        d.timespan = max(d.timespan, other.timespan)
+        d = Dataset(self.name)
+        d.reads = self.reads + other.reads
+        d.nread = self.nread + other.nread
+        d.writes = self.writes + other.writes
+        d.nwritten = self.nwritten + other.nwritten
+        d.nunlinks = self.nunlinks + other.nunlinks
+        d.nunlinked = self.nunlinked + other.nunlinked
+        d.timespan = max(self.timespan, other.timespan)
         return d
 
 
@@ -820,7 +844,7 @@ class DatasetDiffIter:
                 if path in sums:
                     sums[path] += diff
                 else:
-                    sums[path] = Dataset(path) + diff
+                    sums[path] = Dataset(dataset_name=path) + diff
 
         return sums.values()