Add isort via pre-commit

.pre-commit-config.yaml

@@ -1,15 +1,30 @@
 ---
-# black complains loudly that fio-histo-log-pctile.py is not a python file,
-# which it isn't, so ignore it.
-exclude: (agent/bench-scripts/test-bin/fio-histo-log-pctiles.py)
+# `black` complains loudly that fio-histo-log-pctile.py is not a python file,
+# which it isn't, and also complains about the long forgotten demo.py file, so
+# we ignore them both.
+#
+# We must duplicate these excludes also listed in pyproject.toml because the
+# commands below are explicitly invoked on the files added or changed.  This
+# exclude prevents those checks being run.
+exclude: (agent/bench-scripts/test-bin/fio-histo-log-pctiles\.py|web-server/v0\.3/demo\.py)
 repos:
   - repo: https://gitlab.com/pycqa/flake8
     rev: 4.0.1
     hooks:
-     - id: flake8
+      - id: flake8
+        name: flake8 (python3)
+        language_version: python3
   - repo: https://github.com/python/black.git
     rev: 22.3.0
     hooks:
-        - id: black
-          language_version: python3
-          args: ["--check"]
+      - id: black
+        name: black (python3)
+        language_version: python3
+        args: ["--check"]
+  - repo: https://github.com/pycqa/isort
+    rev: 5.10.1
+    hooks:
+      - id: isort
+        name: isort (python3)
+        language_version: python3
+        args: ["--check"]

pyproject.toml

@@ -11,7 +11,7 @@ known_first_party = ["pbench"]    # separate "pbench" section
 multi_line_output = 3             # "hanging" indent with dedented paren
 force_sort_within_sections = true # don't separate import vs from
 order_by_type = false             # sort alphabetic regardless of case
-skip = ["fio-histo-log-pctiles.py", "web-server/v0.3/demo.py"] # like black
+extend_skip = ["fio-histo-log-pctiles.py", "web-server/v0.3/demo.py"] # like black
 
 [tool.black]
 skip-string-normalization = false