Give warning if runpath disk space is close to full on ert startup

src/ert/config/model_config.py

@@ -1,14 +1,25 @@
 from __future__ import annotations
 
+import contextlib
 import logging
 import os.path
+import shutil
 from datetime import datetime
+from pathlib import Path
 from typing import List, Optional, no_type_check
 
 from pydantic import field_validator
 from pydantic.dataclasses import dataclass
 
-from .parsing import ConfigDict, ConfigKeys, ConfigValidationError, HistorySource
+from ert.shared.status.utils import byte_with_unit
+
+from .parsing import (
+    ConfigDict,
+    ConfigKeys,
+    ConfigValidationError,
+    ConfigWarning,
+    HistorySource,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -37,6 +48,9 @@ def str_to_datetime(date_str: str) -> datetime:
 DEFAULT_JOBNAME_FORMAT = "<CONFIG_FILE>-<IENS>"
 DEFAULT_ECLBASE_FORMAT = "ECLBASE<IENS>"
 
+FULL_DISK_PERCENTAGE_THRESHOLD = 0.97
+MINIMUM_BYTES_LEFT_ON_DISK = 200 * 1024**3  # 200 GB required
+
 
 @dataclass
 class ModelConfig:
@@ -75,6 +89,19 @@ def validate_runpath(cls, runpath_format_string: str) -> str:
                 f"`{runpath_format_string}`. Valid example: "
                 f"`{DEFAULT_RUNPATH}` "
             )
+        with contextlib.suppress(Exception):
+            mount_dir = _get_mount_directory(runpath_format_string)
+            total, used, free = shutil.disk_usage(mount_dir)
+            percentage_used = used / total
+            if (
+                percentage_used > FULL_DISK_PERCENTAGE_THRESHOLD
+                and free < MINIMUM_BYTES_LEFT_ON_DISK
+            ):
+                msg = (
+                    f"Little space left in runpath, only {byte_with_unit(free)} free on {mount_dir !s}."
+                    " Consider cleaning up disk before running simulations."
+                )
+                ConfigWarning.warn(msg)
         return result
 
     @field_validator("jobname_format_string", mode="before")
@@ -134,3 +161,12 @@ def _replace_runpath_format(format_string: str) -> str:
     format_string = format_string.replace("%d", "<IENS>", 1)
     format_string = format_string.replace("%d", "<ITER>", 1)
     return format_string
+
+
+def _get_mount_directory(runpath: str) -> Path:
+    path = Path(runpath).absolute()
+
+    while not path.is_mount():
+        path = path.parent
+
+    return path

tests/ert/unit_tests/config/test_model_config.py

@@ -1,7 +1,10 @@
+from pathlib import Path
+from unittest.mock import patch
+
 import pytest
 
 from ert.config import ModelConfig
-from ert.config.parsing import ConfigKeys, ConfigValidationError
+from ert.config.parsing import ConfigKeys, ConfigValidationError, ConfigWarning
 
 
 def test_default_model_config_run_path(tmpdir):
@@ -61,3 +64,13 @@ def test_that_invalid_time_map_file_raises_config_validation_error(tmpdir):
 
         with pytest.raises(ConfigValidationError, match="Could not read timemap file"):
             _ = ModelConfig.from_dict({ConfigKeys.TIME_MAP: "time_map.txt"})
+
+
+def test_warning_when_full_disk(tmp_path):
+    Path(tmp_path / "simulations").mkdir()
+    runpath = "simulations/realization-%d/iter-%d"
+    msg = "Little space left in runpath, only 2.00 B free on"
+    with patch(
+        "ert.config.model_config.shutil.disk_usage", return_value=(100, 98, 2)
+    ), pytest.warns(ConfigWarning, match=msg):
+        _ = ModelConfig(num_realizations=1, runpath_format_string=runpath)