From 6a5fec6dfd94ac8e51ee74ec9389aba8d4c6d521 Mon Sep 17 00:00:00 2001
From: Tobias Raabe <raabe@posteo.de>
Date: Sun, 14 Aug 2022 17:54:15 +0200
Subject: [PATCH 1/7] Remove most code related to parsing the delay.

---
 src/pytask_parallel/build.py     |  9 ---------
 src/pytask_parallel/callbacks.py | 16 ----------------
 src/pytask_parallel/config.py    |  9 +--------
 tests/test_callbacks.py          | 19 -------------------
 tests/test_cli.py                | 27 ---------------------------
 tests/test_config.py             |  2 --
 tests/test_execute.py            | 29 -----------------------------
 7 files changed, 1 insertion(+), 110 deletions(-)
 delete mode 100644 tests/test_cli.py

diff --git a/src/pytask_parallel/build.py b/src/pytask_parallel/build.py
index 65c8b5d..d16a674 100644
--- a/src/pytask_parallel/build.py
+++ b/src/pytask_parallel/build.py
@@ -29,14 +29,5 @@ def pytask_extend_command_line_interface(cli: click.Group) -> None:
             ),
             default=None,
         ),
-        click.Option(
-            ["--delay"],
-            help=(
-                "Delay between checking whether tasks have finished.  [default: 0.1 "
-                "(seconds)]"
-            ),
-            metavar="NUMBER > 0",
-            default=None,
-        ),
     ]
     cli.commands["build"].params.extend(additional_parameters)
diff --git a/src/pytask_parallel/callbacks.py b/src/pytask_parallel/callbacks.py
index 1c28ad9..6061f4c 100644
--- a/src/pytask_parallel/callbacks.py
+++ b/src/pytask_parallel/callbacks.py
@@ -33,19 +33,3 @@ def parallel_backend_callback(value: Any) -> str | None:
             f"parallel_backend has to be one of {list(PARALLEL_BACKENDS)}."
         )
     return value
-
-
-def delay_callback(value: Any) -> float | None:
-    """Validate the delay option."""
-    if value in [None, "None", "none"]:
-        value = None
-    else:
-        try:
-            value = float(value)
-        except ValueError:
-            pass
-
-        if not (isinstance(value, float) and value > 0):
-            raise ValueError("delay has to be a number greater than 0.")
-
-    return value
diff --git a/src/pytask_parallel/config.py b/src/pytask_parallel/config.py
index d8ac251..a329900 100644
--- a/src/pytask_parallel/config.py
+++ b/src/pytask_parallel/config.py
@@ -7,7 +7,6 @@
 
 from pytask import hookimpl
 from pytask_parallel.backends import PARALLEL_BACKENDS_DEFAULT
-from pytask_parallel.callbacks import delay_callback
 from pytask_parallel.callbacks import n_workers_callback
 from pytask_parallel.callbacks import parallel_backend_callback
 
@@ -29,13 +28,7 @@ def pytask_parse_config(
     if config["n_workers"] == "auto":
         config["n_workers"] = max(os.cpu_count() - 1, 1)
 
-    config["delay"] = _get_first_non_none_value(
-        config_from_cli,
-        config_from_file,
-        key="delay",
-        default=0.1,
-        callback=delay_callback,
-    )
+    config["delay"] = 0.1
 
     config["parallel_backend"] = _get_first_non_none_value(
         config_from_cli,
diff --git a/tests/test_callbacks.py b/tests/test_callbacks.py
index bfb7473..40555a7 100644
--- a/tests/test_callbacks.py
+++ b/tests/test_callbacks.py
@@ -4,7 +4,6 @@
 
 import pytest
 from pytask_parallel.backends import PARALLEL_BACKENDS
-from pytask_parallel.callbacks import delay_callback
 from pytask_parallel.callbacks import n_workers_callback
 from pytask_parallel.callbacks import parallel_backend_callback
 
@@ -45,21 +44,3 @@ def test_n_workers_callback(value, expectation):
 def test_parallel_backend_callback(value, expectation):
     with expectation:
         parallel_backend_callback(value)
-
-
-@pytest.mark.unit
-@pytest.mark.parametrize(
-    "value, expectation",
-    [
-        (-1, pytest.raises(ValueError)),
-        (0.1, does_not_raise()),
-        (1, does_not_raise()),
-        ("asdad", pytest.raises(ValueError)),
-        (None, does_not_raise()),
-        ("None", does_not_raise()),
-        ("none", does_not_raise()),
-    ],
-)
-def test_delay_callback(value, expectation):
-    with expectation:
-        delay_callback(value)
diff --git a/tests/test_cli.py b/tests/test_cli.py
deleted file mode 100644
index f9cb0ec..0000000
--- a/tests/test_cli.py
+++ /dev/null
@@ -1,27 +0,0 @@
-from __future__ import annotations
-
-import textwrap
-from time import time
-
-import pytest
-from pytask import cli
-from pytask import ExitCode
-
-
-@pytest.mark.end_to_end
-def test_delay_via_cli(runner, tmp_path):
-    source = """
-    import pytask
-
-    @pytask.mark.produces("out_1.txt")
-    def task_1(produces):
-        produces.write_text("1")
-    """
-    tmp_path.joinpath("task_dummy.py").write_text(textwrap.dedent(source))
-
-    start = time()
-    result = runner.invoke(cli, [tmp_path.as_posix(), "-n", "2", "--delay", "5"])
-    end = time()
-
-    assert result.exit_code == ExitCode.OK
-    assert end - start > 5
diff --git a/tests/test_config.py b/tests/test_config.py
index faca99f..b399030 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -35,8 +35,6 @@ def test_interplay_between_debugging_and_parallel(tmp_path, pdb, n_workers, expe
         ("n_workers", "auto", ExitCode.OK),
         ("n_workers", 1, ExitCode.OK),
         ("n_workers", 2, ExitCode.OK),
-        ("delay", 0.1, ExitCode.OK),
-        ("delay", 1, ExitCode.OK),
         ("parallel_backend", "unknown_backend", ExitCode.CONFIGURATION_FAILED),
     ]
     + [
diff --git a/tests/test_execute.py b/tests/test_execute.py
index 495d849..7453db8 100644
--- a/tests/test_execute.py
+++ b/tests/test_execute.py
@@ -141,35 +141,6 @@ def myfunc():
     assert exception is None
 
 
-@pytest.mark.end_to_end
-@pytest.mark.parametrize("parallel_backend", PARALLEL_BACKENDS)
-def test_parallel_execution_delay(tmp_path, parallel_backend):
-    source = """
-    import pytask
-
-    @pytask.mark.produces("out_1.txt")
-    def task_1(produces):
-        produces.write_text("1")
-
-    @pytask.mark.produces("out_2.txt")
-    def task_2(produces):
-        produces.write_text("2")
-    """
-    tmp_path.joinpath("task_dummy.py").write_text(textwrap.dedent(source))
-
-    session = main(
-        {
-            "paths": tmp_path,
-            "delay": 3,
-            "n_workers": 2,
-            "parallel_backend": parallel_backend,
-        }
-    )
-
-    assert session.exit_code == ExitCode.OK
-    assert 3 < session.execution_end - session.execution_start < 10
-
-
 @pytest.mark.end_to_end
 @pytest.mark.parametrize("parallel_backend", PARALLEL_BACKENDS)
 def test_stop_execution_when_max_failures_is_reached(tmp_path, parallel_backend):

From d542e1c0180bf4abcc553d262189634995bf92f3 Mon Sep 17 00:00:00 2001
From: Tobias Raabe <raabe@posteo.de>
Date: Sun, 14 Aug 2022 18:02:46 +0200
Subject: [PATCH 2/7] add to changes.

---
 CHANGES.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGES.md b/CHANGES.md
index 45e4caf..86662c6 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -9,6 +9,7 @@ releases are available on [PyPI](https://pypi.org/project/pytask-parallel) and
 
 - {pull}`43` adds docformatter.
 - {pull}`44` allows to capture warnings from subprocesses. Fixes {issue}`41`.
+- {pull}`45` replaces the delay command line option with an internal, dynamic parameter.
 
 ## 0.2.0 - 2022-04-15
 

From f76e4789e81771bc5067408595210f656300a290 Mon Sep 17 00:00:00 2001
From: Tobias Raabe <raabe@posteo.de>
Date: Fri, 19 Aug 2022 18:52:45 +0200
Subject: [PATCH 3/7] Implement dynamic sleeper.

---
 .pre-commit-config.yaml        |  2 +-
 CHANGES.md                     |  1 +
 src/pytask_parallel/execute.py | 32 +++++++++++++++++++++++++++++++-
 tests/test_execute.py          | 22 ++++++++++++++++++++++
 4 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 2b45d7a..3151086 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -31,7 +31,7 @@ repos:
     rev: v2.0.0
     hooks:
     -   id: setup-cfg-fmt
--   repo: https://github.com/myint/docformatter
+-   repo: https://github.com/PYCQA/docformatter
     rev: v1.4
     hooks:
     -   id: docformatter
diff --git a/CHANGES.md b/CHANGES.md
index 86662c6..79ea50c 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -10,6 +10,7 @@ releases are available on [PyPI](https://pypi.org/project/pytask-parallel) and
 - {pull}`43` adds docformatter.
 - {pull}`44` allows to capture warnings from subprocesses. Fixes {issue}`41`.
 - {pull}`45` replaces the delay command line option with an internal, dynamic parameter.
+  Fixes {issue}`41`.
 
 ## 0.2.0 - 2022-04-15
 
diff --git a/src/pytask_parallel/execute.py b/src/pytask_parallel/execute.py
index b9a750e..a614cc8 100644
--- a/src/pytask_parallel/execute.py
+++ b/src/pytask_parallel/execute.py
@@ -9,7 +9,9 @@
 from types import TracebackType
 from typing import Any
 from typing import Callable
+from typing import List
 
+import attr
 import cloudpickle
 from pybaum.tree_util import tree_map
 from pytask import console
@@ -65,6 +67,7 @@ def pytask_execute_build(session: Session) -> bool | None:
         with parallel_backend(max_workers=session.config["n_workers"]) as executor:
 
             session.executor = executor
+            sleeper = _Sleeper()
 
             while session.scheduler.is_active():
 
@@ -96,6 +99,10 @@ def pytask_execute_build(session: Session) -> bool | None:
                             running_tasks[task_name] = session.hook.pytask_execute_task(
                                 session=session, task=task
                             )
+                            sleeper.reset()
+
+                    if not ready_tasks:
+                        sleeper.increment()
 
                     for task_name in list(running_tasks):
                         future = running_tasks[task_name]
@@ -146,7 +153,7 @@ def pytask_execute_build(session: Session) -> bool | None:
                     if session.should_stop:
                         break
                     else:
-                        time.sleep(session.config["delay"])
+                        sleeper.sleep()
                 except KeyboardInterrupt:
                     break
 
@@ -316,3 +323,26 @@ def _create_kwargs_for_task(task: Task) -> dict[Any, Any]:
             kwargs[arg_name] = tree_map(lambda x: x.value, attribute)
 
     return kwargs
+
+
+@attr.s(kw_only=True)
+class _Sleeper:
+    """A sleeper that always sleeps a bit and up to 1 second if you don't wake it up.
+
+    This class controls when the next iteration of the execution loop starts. If new
+    tasks are scheduled, the time spent sleeping is reset to a lower value.
+
+    """
+
+    timings = attr.ib(type=List[float], default=[(i / 10) ** 2 for i in range(1, 11)])
+    timing_idx = attr.ib(type=int, default=0)
+
+    def reset(self) -> None:
+        self.timing_idx = 0
+
+    def increment(self) -> None:
+        if self.timing_idx < len(self.timings) - 1:
+            self.timing_idx += 1
+
+    def sleep(self) -> None:
+        time.sleep(self.timings[self.timing_idx])
diff --git a/tests/test_execute.py b/tests/test_execute.py
index 7453db8..e9306d0 100644
--- a/tests/test_execute.py
+++ b/tests/test_execute.py
@@ -11,6 +11,7 @@
 from pytask import main
 from pytask import Task
 from pytask_parallel.backends import PARALLEL_BACKENDS
+from pytask_parallel.execute import _Sleeper
 from pytask_parallel.execute import DefaultBackendNameSpace
 from pytask_parallel.execute import ProcessesNameSpace
 
@@ -296,3 +297,24 @@ def task_example(produces):
     warnings_block = result.output.split("Warnings")[1]
     assert "task_example.py::task_example[0]" in warnings_block
     assert "task_example.py::task_example[1]" in warnings_block
+
+
+def test_sleeper():
+    sleeper = _Sleeper(timings=[1, 2, 3], timing_idx=0)
+
+    assert sleeper.timings == [1, 2, 3]
+    assert sleeper.timing_idx == 0
+
+    sleeper.increment()
+    assert sleeper.timing_idx == 1
+
+    sleeper.increment()
+    assert sleeper.timing_idx == 2
+
+    sleeper.reset()
+    assert sleeper.timing_idx == 0
+
+    start = time.time()
+    sleeper.sleep()
+    end = time.time()
+    assert 1 <= end - start <= 1.000001

From bb2d97027f5f4d0f79741fd50b66f338187d27ac Mon Sep 17 00:00:00 2001
From: Tobias Raabe <raabe@posteo.de>
Date: Fri, 19 Aug 2022 18:55:13 +0200
Subject: [PATCH 4/7] Fix test.

---
 tests/test_execute.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/test_execute.py b/tests/test_execute.py
index e9306d0..6c6a7cd 100644
--- a/tests/test_execute.py
+++ b/tests/test_execute.py
@@ -2,8 +2,8 @@
 
 import pickle
 import textwrap
+import time
 from pathlib import Path
-from time import time
 
 import pytest
 from pytask import cli
@@ -317,4 +317,4 @@ def test_sleeper():
     start = time.time()
     sleeper.sleep()
     end = time.time()
-    assert 1 <= end - start <= 1.000001
+    assert 1 <= end - start <= 1.01

From 2e5094b6e950f214d5387adb84b1dabf098de57c Mon Sep 17 00:00:00 2001
From: Tobias Raabe <raabe@posteo.de>
Date: Fri, 19 Aug 2022 19:31:15 +0200
Subject: [PATCH 5/7] Prepare release.

---
 CHANGES.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CHANGES.md b/CHANGES.md
index 73dce65..b303614 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -5,7 +5,7 @@ chronological order. Releases follow [semantic versioning](https://semver.org/)
 releases are available on [PyPI](https://pypi.org/project/pytask-parallel) and
 [Anaconda.org](https://anaconda.org/conda-forge/pytask-parallel).
 
-## 0.2.1 - 2022-08-xx
+## 0.2.1 - 2022-08-19
 
 - {pull}`43` adds docformatter.
 - {pull}`44` allows to capture warnings from subprocesses. Fixes {issue}`41`.

From fd839bd6622c3a95d65686dd285a64ff4be9f0a5 Mon Sep 17 00:00:00 2001
From: Tobias Raabe <raabe@posteo.de>
Date: Fri, 19 Aug 2022 19:37:19 +0200
Subject: [PATCH 6/7] Fix tests.

---
 CHANGES.md            | 2 +-
 tests/test_execute.py | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index b303614..1591ce8 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -11,7 +11,7 @@ releases are available on [PyPI](https://pypi.org/project/pytask-parallel) and
 - {pull}`44` allows to capture warnings from subprocesses. Fixes {issue}`41`.
 - {pull}`45` replaces the delay command line option with an internal, dynamic parameter.
   Fixes {issue}`41`.
-- {pull}`46` adds a dynamic sleep duration during the execution.
+- {pull}`46` adds a dynamic sleep duration during the execution. Fixes {issue}`42`.
 
 ## 0.2.0 - 2022-04-15
 
diff --git a/tests/test_execute.py b/tests/test_execute.py
index 6c6a7cd..6f6d8f8 100644
--- a/tests/test_execute.py
+++ b/tests/test_execute.py
@@ -2,8 +2,8 @@
 
 import pickle
 import textwrap
-import time
 from pathlib import Path
+from time import time
 
 import pytest
 from pytask import cli
@@ -314,7 +314,7 @@ def test_sleeper():
     sleeper.reset()
     assert sleeper.timing_idx == 0
 
-    start = time.time()
+    start = time()
     sleeper.sleep()
-    end = time.time()
+    end = time()
     assert 1 <= end - start <= 1.01

From e0b5cc82f3f988a08560c10ddc5568ad1f13a992 Mon Sep 17 00:00:00 2001
From: Tobias Raabe <raabe@posteo.de>
Date: Fri, 19 Aug 2022 19:46:53 +0200
Subject: [PATCH 7/7] Make test less flaky.

---
 tests/test_execute.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/test_execute.py b/tests/test_execute.py
index 6f6d8f8..958e6e4 100644
--- a/tests/test_execute.py
+++ b/tests/test_execute.py
@@ -317,4 +317,4 @@ def test_sleeper():
     start = time()
     sleeper.sleep()
     end = time()
-    assert 1 <= end - start <= 1.01
+    assert 1 <= end - start <= 2