Fix IERS download issue in integration tests CI

docs/changes/2129.bugfix.md

@@ -0,0 +1 @@
+Disable Astropy IERS auto-download in offline/test mode to prevent network timeouts and spurious warnings causing test failures.

src/simtools/application_control.py

@@ -7,6 +7,8 @@
 from dataclasses import dataclass
 from pathlib import Path
 
+from astropy.utils import iers
+
 import simtools.utils.general as gen
 from simtools import dependencies, version
 from simtools.configuration import configurator
@@ -20,6 +22,26 @@
 ]
 
 
+def _configure_iers_from_env():
+    """
+    Configure Astropy IERS behavior based on environment variables.
+
+    This disables network access for IERS tables when running in offline mode.
+
+    Controlled via:
+        SIMTOOLS_OFFLINE_IERS=1
+    """
+    if os.getenv("SIMTOOLS_OFFLINE_IERS") != "1":
+        return
+
+    if iers is None:
+        return  # nothing to configure
+
+    iers.conf.auto_download = False
+    iers.conf.use_network = False
+    iers.conf.iers_degraded_accuracy = "warn"
+
+
 def setup_logging(logger_name=None, log_level="INFO", log_file=None):
     """
     Set up logging configuration.
@@ -282,6 +304,8 @@ def main():
             app_context.logger.info("Starting application")
             # ... rest of application logic
     """
+    _configure_iers_from_env()
+
     args_dict, db_config = parse_function()
     config.load(
         args_dict,

src/simtools/production_configuration/generate_production_grid.py

@@ -71,7 +71,6 @@ def __init__(
             telescope names when matching lookup-table telescope selections.
         """
         self._logger = logging.getLogger(__name__)
-
         self.axes = axes["axes"] if "axes" in axes else axes
         self.coordinate_system = coordinate_system
         self.observing_location = (

tests/integration_tests/test_applications_from_config.py

@@ -3,6 +3,7 @@
 
 import copy
 import logging
+import os
 import subprocess
 from pathlib import Path
 
@@ -69,7 +70,16 @@ def test_applications_from_config(tmp_test_directory, config, request):
         pytest.skip(str(exc))
 
     logger.info(f"Running application: {cmd}")
-    result = subprocess.run(cmd, shell=True, input="y\n", capture_output=True, text=True)
+    env = os.environ.copy()
+    env["SIMTOOLS_OFFLINE_IERS"] = "1"
+    result = subprocess.run(
+        cmd,
+        shell=True,
+        input="y\n",
+        capture_output=True,
+        text=True,
+        env=env,
+    )
     msg = f"Command {cmd!r} failed. stdout:\n{result.stdout}\nstderr:\n{result.stderr}"
     assert result.returncode == 0, msg
 

tests/unit_tests/production_configuration/test_generate_production_grid.py

@@ -637,3 +637,31 @@ def test_missing_observing_time(grid_gen):
 
     with pytest.raises(ValueError, match="Observing time is not set"):
         grid_gen.convert_altaz_to_radec(45 * u.deg, 30 * u.deg)
+
+
+def test_iers_not_modified_without_env(monkeypatch):
+    from simtools.application_control import _configure_iers_from_env
+
+    iers.conf.auto_download = True
+
+    monkeypatch.delenv("SIMTOOLS_OFFLINE_IERS", raising=False)
+
+    _configure_iers_from_env()
+
+    GridGeneration(axes={"axes": {}})
+
+    assert iers.conf.auto_download is True
+
+
+def test_iers_disabled_with_env(monkeypatch):
+    from simtools.application_control import _configure_iers_from_env
+
+    iers.conf.auto_download = True
+
+    monkeypatch.setenv("SIMTOOLS_OFFLINE_IERS", "1")
+
+    _configure_iers_from_env()
+
+    GridGeneration(axes={"axes": {}})
+
+    assert iers.conf.auto_download is False

tests/unit_tests/production_configuration/test_plot_production_grid.py

@@ -407,3 +407,53 @@ def test_plot_inferred_radec_grid_logs_no_tracks(tmp_test_directory, caplog):
         assert "No inferred RA/Dec grid tracks available for plotting" in caplog.text
     finally:
         plt.close(figure)
+
+
+def test_iers_disabled_with_env_plotter(monkeypatch, tmp_test_directory):
+    from simtools.application_control import _configure_iers_from_env
+
+    iers.conf.auto_download = True
+    iers.conf.auto_max_age = 30
+
+    monkeypatch.setenv("SIMTOOLS_OFFLINE_IERS", "1")
+
+    _configure_iers_from_env()
+
+    grid_file = _write_grid_file(
+        tmp_test_directory,
+        "grid.ecsv",
+        [{"azimuth": 0.0, "zenith_angle": 0.0}],
+    )
+
+    _create_plotter(
+        grid_file=grid_file,
+        observation_time="2025-01-01 00:00:00",
+        output_path=Path(tmp_test_directory) / "output",
+    )
+
+    assert iers.conf.auto_download is False
+
+
+def test_iers_not_modified_without_env_plotter(monkeypatch, tmp_test_directory):
+    from simtools.application_control import _configure_iers_from_env
+
+    iers.conf.auto_download = True
+    iers.conf.auto_max_age = 30
+
+    monkeypatch.delenv("SIMTOOLS_OFFLINE_IERS", raising=False)
+
+    _configure_iers_from_env()
+
+    grid_file = _write_grid_file(
+        tmp_test_directory,
+        "grid.ecsv",
+        [{"azimuth": 0.0, "zenith_angle": 0.0}],
+    )
+
+    _create_plotter(
+        grid_file=grid_file,
+        observation_time="2025-01-01 00:00:00",
+        output_path=Path(tmp_test_directory) / "output",
+    )
+
+    assert iers.conf.auto_download is True