add log_param/log_params

setup.cfg

@@ -29,6 +29,7 @@ package_dir=
 packages = find:
 install_requires=
     dvc_render[table]>=0.0.8
+    ruamel.yaml>=0.17.11
 
 [options.extras_require]
 tests =

src/dvclive/error.py

@@ -1,5 +1,5 @@
 import os
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Any, Optional
 
 if TYPE_CHECKING:
     from .live import Live
@@ -44,3 +44,27 @@ def __init__(self, name, step):
         super().__init__(
             f"Data '{name}' has already been logged with step '{step}'"
         )
+
+
+class ParameterAlreadyLoggedError(DvcLiveError):
+    def __init__(
+        self, name: str, val: Any, previous_val: Optional[Any] = None
+    ):
+        self.name = name
+        self.val = val
+        self.previous_val = previous_val
+        super().__init__(
+            f"Parameter '{name}={val}' has already been logged"
+            + (
+                f" (previous value={self.previous_val})."
+                if self.previous_val is not None
+                and self.val != self.previous_val
+                else "."
+            )
+        )
+
+
+class InvalidParameterTypeError(DvcLiveError):
+    def __init__(self, val: Any):
+        self.val = val
+        super().__init__(f"Parameter type {type(val)} is not supported.")

src/dvclive/live.py

@@ -7,22 +7,33 @@
 from pathlib import Path
 from typing import Any, Dict, Optional, Union
 
+from ruamel.yaml.representer import RepresenterError
+
 from . import env
 from .data import DATA_TYPES, PLOTS, Image, NumpyEncoder, Scalar
 from .dvc import make_checkpoint
 from .error import (
     ConfigMismatchError,
     InvalidDataTypeError,
+    InvalidParameterTypeError,
     InvalidPlotTypeError,
+    ParameterAlreadyLoggedError,
 )
 from .report import make_report
+from .serialize import dump_yaml, load_yaml
 from .utils import env2bool, nested_update, open_file_in_browser
 
 logging.basicConfig()
 logger = logging.getLogger("dvclive")
 logger.setLevel(os.getenv(env.DVCLIVE_LOGLEVEL, "INFO").upper())
 
 
+# Recursive type aliases are not yet supported by mypy (as of 0.971),
+# so we set type: ignore for ParamLike.
+#  See https://github.com/python/mypy/issues/731#issuecomment-1213482527
+ParamLike = Union[int, float, str, bool, Dict[str, "ParamLike"]]  # type: ignore # noqa
+
+
 class Live:
     DEFAULT_DIR = "dvclive"
 
@@ -54,6 +65,8 @@ def __init__(
         if self._path is None:
             self._path = self.DEFAULT_DIR
 
+        self._params_path = os.path.join(self._path, "params.yaml")
+
         if self._report is not None:
             if not self.report_path:
                 self.report_path = os.path.join(self.dir, f"report.{report}")
@@ -64,23 +77,25 @@ def __init__(
         self._scalars: Dict[str, Any] = OrderedDict()
         self._images: Dict[str, Any] = OrderedDict()
         self._plots: Dict[str, Any] = OrderedDict()
+        self._params: Dict[str, Any] = OrderedDict()
 
+        self._init_paths()
         if self._resume:
+            self._read_params()
             self._step = self.read_step()
             if self._step != 0:
                 self._step += 1
             logger.info(f"Resumed from step {self._step}")
         else:
             self._cleanup()
-            self._init_paths()
 
     def _cleanup(self):
         for data_type in DATA_TYPES:
             shutil.rmtree(
                 Path(self.dir) / data_type.subfolder, ignore_errors=True
             )
 
-        for f in {self.summary_path, self.report_path}:
+        for f in (self.summary_path, self.report_path, self.params_path):
             if os.path.exists(f):
                 os.remove(f)
 
@@ -116,6 +131,10 @@ def init_from_env(self) -> None:
     def dir(self):
         return self._path
 
+    @property
+    def params_path(self):
+        return self._params_path
+
     @property
     def exists(self):
         return os.path.isdir(self.dir)
@@ -130,7 +149,6 @@ def get_step(self) -> int:
     def set_step(self, step: int) -> None:
         if self._step is None:
             self._step = 0
-            self._init_paths()
             for data in chain(
                 self._scalars.values(),
                 self._images.values(),
@@ -191,6 +209,43 @@ def log_plot(self, name, labels, predictions, **kwargs):
         data.dump(val, self._step, **kwargs)
         logger.debug(f"Logged {name}")
 
+    def _read_params(self):
+        if os.path.isfile(self.params_path):
+            params = load_yaml(self.params_path)
+            self._params.update(params)
+
+    def _dump_params(self):
+        try:
+            dump_yaml(self.params_path, self._params)
+        except RepresenterError as exc:
+            raise InvalidParameterTypeError(exc.args) from exc
+
+    def log_params(self, params: Dict[str, ParamLike]):
+        """Saves the given set of parameters (dict) to yaml"""
+        if self._resume and self.get_step():
+            logger.info(
+                "Resuming previous dvclive session, not logging params."
+            )
+            return
+
+        for param_name, param_value in params.items():
+            if param_name in self._params:
+                raise ParameterAlreadyLoggedError(
+                    param_name, param_value, self._params[param_name]
+                )
+
+        self._params.update(params)
+        self._dump_params()
+        logger.debug(f"Logged {params} parameters to {self.params_path}")
+
+    def log_param(
+        self,
+        name: str,
+        val: ParamLike,
+    ):
+        """Saves the given parameter value to yaml"""
+        self.log_params({name: val})
+
     def make_summary(self):
         summary_data = {}
         if self._step is not None:

src/dvclive/serialize.py

@@ -0,0 +1,42 @@
+from collections import OrderedDict
+
+from dvclive.error import DvcLiveError
+
+
+class YAMLError(DvcLiveError):
+    pass
+
+
+class YAMLFileCorruptedError(YAMLError):
+    def __init__(self, path):
+        super().__init__(path, "YAML file structure is corrupted")
+
+
+def load_yaml(path, typ="safe"):
+    from ruamel.yaml import YAML
+    from ruamel.yaml import YAMLError as _YAMLError
+
+    yaml = YAML(typ=typ)
+    with open(path, encoding="utf-8") as fd:
+        try:
+            return yaml.load(fd.read())
+        except _YAMLError:
+            raise YAMLFileCorruptedError(path)
+
+
+def _get_yaml():
+    from ruamel.yaml import YAML
+
+    yaml = YAML()
+    yaml.default_flow_style = False
+
+    # tell Dumper to represent OrderedDict as normal dict
+    yaml_repr_cls = yaml.Representer
+    yaml_repr_cls.add_representer(OrderedDict, yaml_repr_cls.represent_dict)
+    return yaml
+
+
+def dump_yaml(path, data):
+    yaml = _get_yaml()
+    with open(path, "w", encoding="utf-8") as fd:
+        yaml.dump(data, fd)