Add symlink directory for easy log access

csp_gateway/server/config/hydra/job_logging/custom.yaml

@@ -39,9 +39,11 @@ handlers:
     stream: ext://sys.stdout
   file:
     level: DEBUG
-    class: logging.FileHandler
+    class: csp_gateway.server.shared.symlink_file_handler.SymlinkFileHandler
     formatter: whenAndWhere
     filename: ${hydra.runtime.output_dir}/csp-gateway.log
+    log_links_dir: ${hydra.runtime.cwd}/${hydra.job.name}_log_links
+    symlink_filename: ${hydra.job.name}_${now:%Y%m%d_%H%M%S}.log
 root:
   handlers: [console, file]
   level: DEBUG

csp_gateway/server/shared/__init__.py

@@ -1,3 +1,4 @@
 from .adapters import *
 from .channel_selection import *
 from .json_converter import *
+from .symlink_file_handler import *

csp_gateway/server/shared/symlink_file_handler.py

@@ -0,0 +1,58 @@
+import logging
+from pathlib import Path
+from typing import Any
+
+__all__ = ["SymlinkFileHandler"]
+
+log = logging.getLogger(__name__)
+
+
+class SymlinkFileHandler(logging.FileHandler):
+    def __init__(
+        self,
+        filename: str,
+        log_links_dir: str,
+        symlink_filename: str,
+        *args: Any,
+        **kwargs: Any,
+    ) -> None:
+        self.log_links_dir = Path(log_links_dir)
+        self.symlink_filename = symlink_filename
+
+        super().__init__(filename, *args, **kwargs)
+
+        try:
+            self.log_links_dir.mkdir(parents=True, exist_ok=True)
+            log.debug("Ensured symlink directory exists: %s", self.log_links_dir)
+        except (OSError, PermissionError) as e:
+            log.error("Failed to create symlink directory %s: %s", self.log_links_dir, e, exc_info=True)
+            return
+
+        target = Path(self.baseFilename).resolve()
+
+        # Timestamped symlink
+        named_link = self.log_links_dir / self.symlink_filename
+        self._create_file_symlink(target, named_link)
+
+        # Latest symlink
+        self._create_file_symlink(target, self.log_links_dir / "latest.log")
+
+    @staticmethod
+    def _create_file_symlink(target: Path, symlink_path: Path) -> None:
+        if not target.exists():
+            log.error("Target for symlink does not exist: %s", target)
+            return
+
+        tmp = symlink_path.with_suffix(symlink_path.suffix + ".tmp")
+
+        try:
+            if tmp.exists() or tmp.is_symlink():
+                tmp.unlink()
+
+            tmp.symlink_to(target)
+            tmp.replace(symlink_path)
+
+            log.info("Created symlink %s -> %s", symlink_path, target)
+
+        except (OSError, PermissionError) as e:
+            log.error("Failed to create symlink %s: %s", symlink_path, e, exc_info=True)

csp_gateway/tests/server/shared/test_symlink_file_handler.py

@@ -0,0 +1,127 @@
+import logging
+
+from csp_gateway.server.shared.symlink_file_handler import SymlinkFileHandler
+
+
+def test_handler_creates_symlinks(tmp_path):
+    """
+    SymlinkFileHandler should create:
+    - a timestamped symlink
+    - a latest.log symlink
+    """
+
+    # Arrange
+    output_dir = tmp_path / "hydra_output"
+    log_links_dir = tmp_path / "job_log_links"
+
+    output_dir.mkdir()
+    log_links_dir.mkdir()
+
+    log_file = output_dir / "csp-gateway.log"
+
+    symlink_name = "csp-gateway_20260101_120000.log"
+
+    # Act
+    handler = SymlinkFileHandler(
+        filename=str(log_file),
+        log_links_dir=str(log_links_dir),
+        symlink_filename=symlink_name,
+    )
+
+    # Assert
+    assert log_file.exists()
+
+    timestamped_link = log_links_dir / symlink_name
+    latest_link = log_links_dir / "latest.log"
+
+    assert timestamped_link.is_symlink()
+    assert latest_link.is_symlink()
+
+    assert timestamped_link.resolve() == log_file.resolve()
+    assert latest_link.resolve() == log_file.resolve()
+
+    handler.close()
+
+
+def test_handler_creates_log_links_dir_if_missing(tmp_path):
+    output_dir = tmp_path / "hydra_output"
+    output_dir.mkdir()
+
+    log_file = output_dir / "csp-gateway.log"
+    log_file.write_text("log")
+
+    log_links_dir = tmp_path / "missing_log_links"
+
+    handler = SymlinkFileHandler(
+        filename=str(log_file),
+        log_links_dir=str(log_links_dir),
+        symlink_filename="test.log",
+    )
+
+    assert log_links_dir.exists()
+    assert log_links_dir.is_dir()
+
+    handler.close()
+
+
+def test_handler_writes_logs_through_symlink(tmp_path):
+    output_dir = tmp_path / "hydra_output"
+    output_dir.mkdir()
+
+    log_file = output_dir / "csp-gateway.log"
+    log_links_dir = tmp_path / "log_links"
+
+    handler = SymlinkFileHandler(
+        filename=str(log_file),
+        log_links_dir=str(log_links_dir),
+        symlink_filename="test.log",
+    )
+
+    test_logger = logging.getLogger("test_symlink_logger")
+    test_logger.addHandler(handler)
+    test_logger.setLevel(logging.INFO)
+
+    test_logger.info("Test log message")
+    handler.flush()
+
+    latest_symlink = log_links_dir / "latest.log"
+    assert latest_symlink.exists()
+    assert latest_symlink.is_symlink()
+
+    content = latest_symlink.read_text()
+    assert "Test log message" in content
+
+    handler.close()
+    test_logger.removeHandler(handler)
+
+
+def test_latest_symlink_updates_on_new_handler(tmp_path):
+    output_dir1 = tmp_path / "run1"
+    output_dir2 = tmp_path / "run2"
+    output_dir1.mkdir()
+    output_dir2.mkdir()
+
+    log_links_dir = tmp_path / "log_links"
+
+    handler1 = SymlinkFileHandler(
+        filename=str(output_dir1 / "csp-gateway.log"),
+        log_links_dir=str(log_links_dir),
+        symlink_filename="run1.log",
+    )
+
+    latest = log_links_dir / "latest.log"
+    assert latest.is_symlink()
+    assert latest.resolve() == (output_dir1 / "csp-gateway.log").resolve()
+
+    handler1.close()
+
+    handler2 = SymlinkFileHandler(
+        filename=str(output_dir2 / "csp-gateway.log"),
+        log_links_dir=str(log_links_dir),
+        symlink_filename="run2.log",
+    )
+
+    assert latest.is_symlink()
+    assert latest.resolve() == (output_dir2 / "csp-gateway.log").resolve()
+
+    handler2.close()