fix[next]: Guard diskcache creation by file lock

.pre-commit-config.yaml

@@ -102,6 +102,7 @@ repos:
     - devtools==0.12.2
     - diskcache==5.6.3
     - factory-boy==3.3.1
+    - filelock==3.16.1
     - frozendict==2.4.6
     - gridtools-cpp==2.3.8
     - importlib-resources==6.4.5

constraints.txt

@@ -49,7 +49,7 @@ executing==2.1.0          # via devtools, stack-data
 factory-boy==3.3.1        # via gt4py (pyproject.toml), pytest-factoryboy
 faker==33.0.0             # via factory-boy
 fastjsonschema==2.20.0    # via nbformat
-filelock==3.16.1          # via tox, virtualenv
+filelock==3.16.1          # via gt4py (pyproject.toml), tox, virtualenv
 fonttools==4.55.0         # via matplotlib
 fparser==0.1.4            # via dace
 frozendict==2.4.6         # via gt4py (pyproject.toml)
@@ -113,8 +113,8 @@ psutil==6.1.0             # via -r requirements-dev.in, ipykernel, pytest-xdist
 ptyprocess==0.7.0         # via pexpect
 pure-eval==0.2.3          # via stack-data
 pybind11==2.13.6          # via gt4py (pyproject.toml)
-pydantic==2.9.2           # via bump-my-version, pydantic-settings
-pydantic-core==2.23.4     # via pydantic
+pydantic==2.10.0          # via bump-my-version, pydantic-settings
+pydantic-core==2.27.0     # via pydantic
 pydantic-settings==2.6.1  # via bump-my-version
 pydot==3.0.2              # via tach
 pygments==2.18.0          # via -r requirements-dev.in, devtools, ipython, nbmake, rich, sphinx
@@ -159,7 +159,7 @@ stack-data==0.6.3         # via ipython
 stdlib-list==0.10.0       # via tach
 sympy==1.13.3             # via dace
 tabulate==0.9.0           # via gt4py (pyproject.toml)
-tach==0.14.3              # via -r requirements-dev.in
+tach==0.14.4              # via -r requirements-dev.in
 tomli==2.1.0 ; python_version < "3.11"  # via -r requirements-dev.in, black, build, coverage, jupytext, mypy, pip-tools, pyproject-api, pytest, setuptools-scm, tach, tox
 tomli-w==1.0.0            # via tach
 tomlkit==0.13.2           # via bump-my-version

min-extra-requirements-test.txt

@@ -67,6 +67,7 @@ deepdiff==5.6.0
 devtools==0.6
 diskcache==5.6.3
 factory-boy==3.3.0
+filelock==3.0.0
 frozendict==2.3
 gridtools-cpp==2.3.8
 hypothesis==6.0.0

min-requirements-test.txt

@@ -63,6 +63,7 @@ deepdiff==5.6.0
 devtools==0.6
 diskcache==5.6.3
 factory-boy==3.3.0
+filelock==3.0.0
 frozendict==2.3
 gridtools-cpp==2.3.8
 hypothesis==6.0.0

pyproject.toml

@@ -36,6 +36,7 @@ dependencies = [
   'devtools>=0.6',
   'diskcache>=5.6.3',
   'factory-boy>=3.3.0',
+  'filelock>=3.0.0',
   'frozendict>=2.3',
   'gridtools-cpp>=2.3.8,==2.*',
   "importlib-resources>=5.0;python_version<'3.9'",

requirements-dev.txt

@@ -49,7 +49,7 @@ executing==2.1.0          # via -c constraints.txt, devtools, stack-data
 factory-boy==3.3.1        # via -c constraints.txt, gt4py (pyproject.toml), pytest-factoryboy
 faker==33.0.0             # via -c constraints.txt, factory-boy
 fastjsonschema==2.20.0    # via -c constraints.txt, nbformat
-filelock==3.16.1          # via -c constraints.txt, tox, virtualenv
+filelock==3.16.1          # via -c constraints.txt, gt4py (pyproject.toml), tox, virtualenv
 fonttools==4.55.0         # via -c constraints.txt, matplotlib
 fparser==0.1.4            # via -c constraints.txt, dace
 frozendict==2.4.6         # via -c constraints.txt, gt4py (pyproject.toml)
@@ -113,8 +113,8 @@ psutil==6.1.0             # via -c constraints.txt, -r requirements-dev.in, ipyk
 ptyprocess==0.7.0         # via -c constraints.txt, pexpect
 pure-eval==0.2.3          # via -c constraints.txt, stack-data
 pybind11==2.13.6          # via -c constraints.txt, gt4py (pyproject.toml)
-pydantic==2.9.2           # via -c constraints.txt, bump-my-version, pydantic-settings
-pydantic-core==2.23.4     # via -c constraints.txt, pydantic
+pydantic==2.10.0          # via -c constraints.txt, bump-my-version, pydantic-settings
+pydantic-core==2.27.0     # via -c constraints.txt, pydantic
 pydantic-settings==2.6.1  # via -c constraints.txt, bump-my-version
 pydot==3.0.2              # via -c constraints.txt, tach
 pygments==2.18.0          # via -c constraints.txt, -r requirements-dev.in, devtools, ipython, nbmake, rich, sphinx
@@ -158,7 +158,7 @@ stack-data==0.6.3         # via -c constraints.txt, ipython
 stdlib-list==0.10.0       # via -c constraints.txt, tach
 sympy==1.13.3             # via -c constraints.txt, dace
 tabulate==0.9.0           # via -c constraints.txt, gt4py (pyproject.toml)
-tach==0.14.3              # via -c constraints.txt, -r requirements-dev.in
+tach==0.14.4              # via -c constraints.txt, -r requirements-dev.in
 tomli==2.1.0 ; python_version < "3.11"  # via -c constraints.txt, -r requirements-dev.in, black, build, coverage, jupytext, mypy, pip-tools, pyproject-api, pytest, setuptools-scm, tach, tox
 tomli-w==1.0.0            # via -c constraints.txt, tach
 tomlkit==0.13.2           # via -c constraints.txt, bump-my-version

src/gt4py/next/program_processors/runners/gtfn.py

@@ -7,11 +7,14 @@
 # SPDX-License-Identifier: BSD-3-Clause
 
 import functools
+import pathlib
+import tempfile
 import warnings
 from typing import Any, Optional
 
 import diskcache
 import factory
+import filelock
 
 import gt4py._core.definitions as core_defs
 import gt4py.next.allocators as next_allocators
@@ -139,13 +142,34 @@ def fingerprint_compilable_program(inp: stages.CompilableProgram) -> str:
 
 class FileCache(diskcache.Cache):
     """
-    This class extends `diskcache.Cache` to ensure the cache is closed upon deletion,
-    i.e. it ensures that any resources associated with the cache are properly
-    released when the instance is garbage collected.
+    This class extends `diskcache.Cache` to ensure the cache is properly
+    - opened when accessed by multiple processes using a file lock. This guards the creating of the
+    cache object, which has been reported to cause `sqlite3.OperationalError: database is locked`
+    errors and slow startup times when multiple processes access the cache concurrently. While this
+    issue occurred frequently and was observed to be fixed on distributed file systems, the lock
+    does not guarantee correct behavior in particular for accesses to the cache (beyond opening)
+    since the underlying SQLite database is unreliable when stored on an NFS based file system.
+    It does however ensure correctness of concurrent cache accesses on a local file system. See
+    #1745 for more details.
+    - closed upon deletion, i.e. it ensures that any resources associated with the cache are
+    properly released when the instance is garbage collected.
     """
 
+    def __init__(self, directory: Optional[str | pathlib.Path] = None, **settings: Any) -> None:
+        if directory:
+            lock_dir = pathlib.Path(directory).parent
+        else:
+            lock_dir = pathlib.Path(tempfile.gettempdir())
+
+        lock = filelock.FileLock(lock_dir / "file_cache.lock")
+        with lock:
+            super().__init__(directory=directory, **settings)
+
+        self._init_complete = True
+
     def __del__(self) -> None:
-        self.close()
+        if getattr(self, "_init_complete", False):  # skip if `__init__` didn't finished
+            self.close()
 
 
 class GTFNCompileWorkflowFactory(factory.Factory):