SoftFileLock asyncio workaround (#444)

.zenodo.json

@@ -55,6 +55,11 @@
       "name": "Johnson, Charles E.",
       "orcid": "0000-0001-7814-3501"
     },
+    {
+      "affiliation": "FCBG, EPFL",
+      "name": "Wigger, Jeffrey",
+      "orcid": "0000-0003-0978-4326"
+    },
     {
       "affiliation": "MIT, HMS",
       "name": "Ghosh, Satrajit",

pydra/engine/core.py

@@ -36,6 +36,7 @@
     ensure_list,
     record_error,
     hash_function,
+    PydraFileLock,
 )
 from .helpers_file import copyfile_input, template_update
 from .graph import DiGraph
@@ -1007,7 +1008,7 @@ async def _run(self, submitter=None, rerun=False, **kwargs):
             self.create_connections(task)
         lockfile = self.cache_dir / (checksum + ".lock")
         self.hooks.pre_run(self)
-        with SoftFileLock(lockfile):
+        async with PydraFileLock(lockfile):
             # retrieve cached results
             if not (rerun or self.task_rerun):
                 result = self.result()

pydra/engine/helpers.py

@@ -4,7 +4,7 @@
 import attr
 import cloudpickle as cp
 from pathlib import Path
-from filelock import SoftFileLock
+from filelock import SoftFileLock, Timeout
 import os
 import sys
 from hashlib import sha256
@@ -893,3 +893,29 @@ def argstr_formatting(argstr, inputs, value_updates=None):
         .strip()
     )
     return argstr_formatted
+
+
+class PydraFileLock:
+    """Wrapper for filelock's SoftFileLock that makes it work with asyncio."""
+
+    def __init__(self, lockfile):
+        self.lockfile = lockfile
+        self.timeout = 0.1
+
+    async def __aenter__(self):
+        lock = SoftFileLock(self.lockfile)
+        acquired_lock = False
+        while not acquired_lock:
+            try:
+                lock.acquire(timeout=0)
+                acquired_lock = True
+            except Timeout:
+                await asyncio.sleep(self.timeout)
+                if self.timeout <= 2:
+                    self.timeout = self.timeout * 2
+        self.lock = lock
+        return self
+
+    async def __aexit__(self, exc_type, exc_value, traceback):
+        self.lock.release()
+        return None

pydra/engine/tests/test_workflow.py

@@ -27,6 +27,7 @@
 )
 from ..submitter import Submitter
 from ..core import Workflow
+from ... import mark
 
 
 def test_wf_name_conflict1():
@@ -4561,3 +4562,79 @@ def test_graph_5(tmpdir):
     if DOT_FLAG:
         name = f"graph_{sys._getframe().f_code.co_name}"
         exporting_graphs(wf=wf, name=name)
+
+
+@pytest.mark.timeout(20)
+def test_duplicate_input_on_split_wf(tmpdir):
+    """ checking if the workflow gets stuck if it has to run two tasks with equal checksum;
+        This can occur when splitting on a list containing duplicate values.
+    """
+    text = ["test"] * 2
+
+    @mark.task
+    def printer(a):
+        return a
+
+    wf = Workflow(name="wf", input_spec=["text"], cache_dir=tmpdir)
+    wf.split(("text"), text=text)
+
+    wf.add(printer(name="printer1", a=wf.lzin.text))
+
+    wf.set_output([("out1", wf.printer1.lzout.out)])
+
+    with Submitter(plugin="cf", n_procs=6) as sub:
+        sub(wf)
+
+    res = wf.result()
+
+    assert res[0].output.out1 == "test" and res[1].output.out1 == "test"
+
+
+@pytest.mark.timeout(40)
+def test_inner_outer_wf_duplicate(tmpdir):
+    """ checking if the execution gets stuck if there is an inner and outer workflows
+        thar run two nodes with the exact same inputs.
+    """
+    task_list = ["First", "Second"]
+    start_list = [3]
+
+    @mark.task
+    def one_arg(start_number):
+        for k in range(10):
+            start_number += 1
+        return start_number
+
+    @mark.task
+    def one_arg_inner(start_number):
+        for k in range(10):
+            start_number += 1
+        return start_number
+
+    # Outer workflow
+    test_outer = Workflow(
+        name="test_outer", input_spec=["start_number", "task_name"], cache_dir=tmpdir
+    )
+    # Splitting on both arguments
+    test_outer.split(
+        ["start_number", "task_name"], start_number=start_list, task_name=task_list
+    )
+
+    # Inner Workflow
+    test_inner = Workflow(name="test_inner", input_spec=["start_number1"])
+    test_inner.add(
+        one_arg_inner(name="Ilevel1", start_number=test_inner.lzin.start_number1)
+    )
+    test_inner.set_output([("res", test_inner.Ilevel1.lzout.out)])
+
+    # Outer workflow has two nodes plus the inner workflow
+    test_outer.add(one_arg(name="level1", start_number=test_outer.lzin.start_number))
+    test_outer.add(test_inner)
+    test_inner.inputs.start_number1 = test_outer.level1.lzout.out
+
+    test_outer.set_output([("res2", test_outer.test_inner.lzout.res)])
+
+    with Submitter(plugin="cf") as sub:
+        sub(test_outer)
+
+    res = test_outer.result()
+    assert res[0].output.res2 == 23 and res[1].output.res2 == 23

setup.cfg

@@ -35,6 +35,7 @@ test_requires =
     pytest-env
     pytest-xdist < 2.0
     pytest-rerunfailures
+    pytest-timeout
     codecov
     numpy
     psutil
@@ -68,6 +69,7 @@ test =
     pytest-env
     pytest-xdist < 2.0
     pytest-rerunfailures
+    pytest-timeout
     codecov
     numpy
     pyld