Logger: Python API by nitbharambe · Pull Request #1593 · PowerGridModel/power-grid-model

nitbharambe · 2026-09-18T14:47:16Z

Summary of Python API of logger

Public import: from power_grid_model import Logger, LoggerType, both exported from the package root in __init__.py.

class Logger:
    def __init__(
        self,
        logger_type: LoggerType = LoggerType.info,
        *,
        python_logger: logging.Logger | None = None,
        level: int = logging.DEBUG,
    ) -> None: ...

    def __enter__(self) -> Logger: ...
    def __exit__(self, *_: object) -> None: ...

    @property
    def output(self) -> str: ...

    def clear(self) -> None: ...

LoggerType currently has one member: LoggerType.info = 3 (enum.py). (Benchmark to be added when #1598 is available)

Use Logger as a context manager to register it for calculations and unregister it on exit. output returns the accumulated text; clear() empties it. If python_logger is supplied, each non-empty output line is sent at the configured level on exit, then the buffer is cleared. The implementation and detailed behavior are in logger.py.

mgovers · 2026-09-28T10:59:02Z

+class LoggerType(IntEnum):
+    """Logger types for opt-in diagnostic output from calculations.
+
+    Output is non-conclusive and intended as debugging hints for advanced users.
+    """
+
+    do_nothing = 0
+    """Logger that discards all output (no-op). Useful as a typed placeholder."""
+    text = 1
+    """Logger that captures timestamped text messages, including sparse-matrix hints."""
+    benchmark = 2
+    """Logger that captures timing information per calculation phase."""


let's follow the same conventions as for the C API

This looks different from the C side enum PGM_LoggerType. Is that intentional?

@Jerry-Jinfeng-Guo Naming you mean? Renamed to info and then will add benchmark later.

mgovers · 2026-09-28T11:01:19Z

+        self._active: bool = False
+
+    def __del__(self) -> None:
+        if self._active:


should be mutex'ed (or at least be atomic)

mgovers · 2026-09-28T11:01:56Z

+    def __enter__(self) -> "Logger":
+        get_pgc().register_logger(self._logger_ptr)
+        assert_no_error()
+        self._active = True


self._active must be atomic

mgovers · 2026-09-28T11:03:12Z

+        assert_no_error()
+        self._python_logger = python_logger
+        self._level = level
+        self._active: bool = False


must be atomic. Also refer to python/cpython#124366

Did the suggested way in the link.

mgovers · 2026-09-28T11:09:34Z

+        get_pgc().logger_clear(self._logger_ptr)
+        assert_no_error()
+
+    def flush_to_python_logger(self) -> None:


in the future, we will probably want to extend with an asynchronous watcher to obtain the logs on-the-fly while the calculation is running.

To do that, we can extend the MultiThreadedTextLogger with a second buffer or queue/hive of buffers

to that extend, should we make this a private method instead? so that later we can choose to flush differently

I guess so. Made it private. We can specially make it available later if needed

nitbharambe · 2026-09-30T08:36:01Z

+    def __init__(
+        self,
+        logger_type: LoggerType = LoggerType.info,
+        *,
+        python_logger: _logging.Logger | None = None,
+        level: int = _logging.DEBUG,


I feel this would be a bit confusing for users.

Do i rename level -> python_logging_level?

I feel this would be a bit confusing for users.

Do i rename level -> python_logging_level?

why not keep the same loglevel for both python and C++ where it makes sense?

LoggerType.info -> _logging.INFO

LoggerType.benchmark -> _logging.DEBUG

or you can do something like override_python_log_level?

Also maybe we need to consider if in the future we decide to support multiple python log levels, then we can get something like

LoggerType.warning_only -> _logging.WARNING
LoggerType.info_only -> _logging.INFO
LoggerType.debug_only -> _logging.DEBUG

as opposed to one LoggerType.info that sends warning level C++ logs to _logging.INFO, which is not great, of course

Please also do note that there may be multi-line C++ core logs all sent to the Python logger in one single event, so maybe we need to split the output

Regarding 2nd comment, we already split at new lines when we flush to python logger. Is there a requirement to have multiline logs under a single log of python?

_flush_to_python_logger can also be customized in such a case

Regarding 1st, Since there is a lot of logic involved with levels, lets just let user determine which PGM-internal logging levels map to which of python logging levels.
So we recommend them creating LoggerType.info with _logging.info but not restrict them from creating LoggerType.some_type -> _logging.info

Regarding 2nd comment, we already split at new lines when we flush to python logger. Is there a requirement to have multiline logs under a single log of python?

_flush_to_python_logger can also be customized in such a case

ahhh sorry didn't realize that. i think it's fine. logs aren't meant to be fully stable anyways

mgovers

the rest LGTM

mgovers · 2026-09-30T12:12:23Z

+    def __init__(
+        self,
+        logger_type: LoggerType = LoggerType.info,
+        *,
+        python_logger: _logging.Logger | None = None,
+        level: int = _logging.DEBUG,


Please also do note that there may be multi-line C++ core logs all sent to the Python logger in one single event, so maybe we need to split the output

mgovers · 2026-09-30T12:12:46Z

+    Output is non-conclusive and intended as debugging hints for advanced users.
+    """
+
+    info = 3


no benchmark yet?

Adding. Was waiting on it being available in main. Now added.

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

sonarqubecloud · 2026-09-30T13:42:05Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

nitbharambe added this pull request to stack #1592 September 18, 2026 14:47

nitbharambe changed the title ~~input from poc~~ Logger: Python API Sep 21, 2026

mgovers force-pushed the pgm/feature/logger-python-api-implementation branch 2 times, most recently from ee1b59e to 468e367 Compare September 24, 2026 11:59

nitbharambe marked this pull request as ready for review September 25, 2026 14:25

mgovers reviewed Sep 28, 2026

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Comment thread src/power_grid_model/_core/logger.py Outdated

mgovers reviewed Sep 28, 2026

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nitbharambe force-pushed the pgm/feature/logger-python-api-implementation branch from 3e7516a to d113cdd Compare September 28, 2026 15:57

nitbharambe added the feature New feature or request label Sep 29, 2026

nitbharambe force-pushed the pgm/feature/logger-python-api-implementation branch from 9174b57 to f0a8907 Compare September 29, 2026 09:09

Base automatically changed from pgm/feature/logger-api-implementation to main September 29, 2026 13:06

mgovers force-pushed the pgm/feature/logger-python-api-implementation branch from f0a8907 to 2e3f9d7 Compare September 29, 2026 13:06

figueroa1395 assigned nitbharambe Sep 29, 2026

nitbharambe force-pushed the pgm/feature/logger-python-api-implementation branch from 2f3ac47 to 1cddc94 Compare September 29, 2026 15:27

mgovers reviewed Sep 30, 2026

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Comment thread src/power_grid_model/_core/logger.py

nitbharambe commented Sep 30, 2026

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mgovers reviewed Sep 30, 2026

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nitbharambe added 7 commits September 30, 2026 15:27

input from poc

b73741a

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

python logger tests

7b2087f

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address comments

ccdf340

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

add resource warning test

4506874

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

add missed __all__

7b4058a

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

rename to clear content

5944bcb

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

add a counter instead + test

a83c91e

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

nitbharambe added 4 commits September 30, 2026 15:27

address mypy

9cfa231

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

ignore ruff

ad10686

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

add python doc

7212642

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

update stale docstring

06384c7

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

nitbharambe force-pushed the pgm/feature/logger-python-api-implementation branch from fdb11d5 to 06384c7 Compare September 30, 2026 13:27

add benchmark enum

cc099a4

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

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sonarqubecloud Bot commented Sep 30, 2026

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nitbharambe commented Sep 18, 2026 •

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