mlflow.pytorch
The mlflow.pytorch
module provides an API for logging and loading PyTorch models. This module
exports PyTorch models with the following flavors:
- PyTorch (native) format
This is the main flavor that can be loaded back into PyTorch.
mlflow.pyfunc
Produced for use by generic pyfunc-based deployment tools and batch inference.
-
mlflow.pytorch.
autolog
(log_every_n_epoch=1, log_every_n_step=None, log_models=True, log_datasets=True, disable=False, exclusive=False, disable_for_unsupported_versions=False, silent=False, registered_model_name=None, extra_tags=None, checkpoint=True, checkpoint_monitor='val_loss', checkpoint_mode='min', checkpoint_save_best_only=True, checkpoint_save_weights_only=False, checkpoint_save_freq='epoch')[source] Note
Autologging is known to be compatible with the following package versions:
1.9.0
<=torch
<=2.4.0
. Autologging may not succeed when used with package versions outside of this range.Enables (or disables) and configures autologging from PyTorch Lightning to MLflow.
Autologging is performed when you call the fit method of pytorch_lightning.Trainer().
Explore the complete PyTorch MNIST for an expansive example with implementation of additional lightening steps.
Note: Full autologging is only supported for PyTorch Lightning models, i.e., models that subclass pytorch_lightning.LightningModule. Autologging support for vanilla PyTorch (ie models that only subclass torch.nn.Module) only autologs calls to torch.utils.tensorboard.SummaryWriter’s
add_scalar
andadd_hparams
methods to mlflow. In this case, there’s also no notion of an “epoch”.- Parameters
log_every_n_epoch – If specified, logs metrics once every n epochs. By default, metrics are logged after every epoch.
log_every_n_step – If specified, logs batch metrics once every n training step. By default, metrics are not logged for steps. Note that setting this to 1 can cause performance issues and is not recommended. Metrics are logged against Lightning’s global step number, and when multiple optimizers are used it is assumed that all optimizers are stepped in each training step.
log_models – If
True
, trained models are logged as MLflow model artifacts. IfFalse
, trained models are not logged.log_datasets – If
True
, dataset information is logged to MLflow Tracking. IfFalse
, dataset information is not logged.disable – If
True
, disables the PyTorch Lightning autologging integration. IfFalse
, enables the PyTorch Lightning autologging integration.exclusive – If
True
, autologged content is not logged to user-created fluent runs. IfFalse
, autologged content is logged to the active fluent run, which may be user-created.disable_for_unsupported_versions – If
True
, disable autologging for versions of pytorch and pytorch-lightning that have not been tested against this version of the MLflow client or are incompatible.silent – If
True
, suppress all event logs and warnings from MLflow during PyTorch Lightning autologging. IfFalse
, show all events and warnings during PyTorch Lightning autologging.registered_model_name – If given, each time a model is trained, it is registered as a new model version of the registered model with this name. The registered model is created if it does not already exist.
extra_tags – A dictionary of extra tags to set on each managed run created by autologging.
checkpoint – Enable automatic model checkpointing, this feature only supports pytorch-lightning >= 1.6.0.
checkpoint_monitor – In automatic model checkpointing, the metric name to monitor if you set model_checkpoint_save_best_only to True.
checkpoint_save_best_only – If True, automatic model checkpointing only saves when the model is considered the “best” model according to the quantity monitored and previous checkpoint model is overwritten.
checkpoint_mode – one of {“min”, “max”}. In automatic model checkpointing, if save_best_only=True, the decision to overwrite the current save file is made based on either the maximization or the minimization of the monitored quantity.
checkpoint_save_weights_only – In automatic model checkpointing, if True, then only the model’s weights will be saved. Otherwise, the optimizer states, lr-scheduler states, etc are added in the checkpoint too.
checkpoint_save_freq – “epoch” or integer. When using “epoch”, the callback saves the model after each epoch. When using integer, the callback saves the model at end of this many batches. Note that if the saving isn’t aligned to epochs, the monitored metric may potentially be less reliable (it could reflect as little as 1 batch, since the metrics get reset every epoch). Defaults to “epoch”.
import os import lightning as L import torch from torch.nn import functional as F from torch.utils.data import DataLoader, Subset from torchmetrics import Accuracy from torchvision import transforms from torchvision.datasets import MNIST import mlflow.pytorch from mlflow import MlflowClient class MNISTModel(L.LightningModule): def __init__(self): super().__init__() self.l1 = torch.nn.Linear(28 * 28, 10) self.accuracy = Accuracy("multiclass", num_classes=10) def forward(self, x): return torch.relu(self.l1(x.view(x.size(0), -1))) def training_step(self, batch, batch_nb): x, y = batch logits = self(x) loss = F.cross_entropy(logits, y) pred = logits.argmax(dim=1) acc = self.accuracy(pred, y) # PyTorch `self.log` will be automatically captured by MLflow. self.log("train_loss", loss, on_epoch=True) self.log("acc", acc, on_epoch=True) return loss def configure_optimizers(self): return torch.optim.Adam(self.parameters(), lr=0.02) def print_auto_logged_info(r): tags = {k: v for k, v in r.data.tags.items() if not k.startswith("mlflow.")} artifacts = [f.path for f in MlflowClient().list_artifacts(r.info.run_id, "model")] print(f"run_id: {r.info.run_id}") print(f"artifacts: {artifacts}") print(f"params: {r.data.params}") print(f"metrics: {r.data.metrics}") print(f"tags: {tags}") # Initialize our model. mnist_model = MNISTModel() # Load MNIST dataset. train_ds = MNIST( os.getcwd(), train=True, download=True, transform=transforms.ToTensor() ) # Only take a subset of the data for faster training. indices = torch.arange(32) train_ds = Subset(train_ds, indices) train_loader = DataLoader(train_ds, batch_size=8) # Initialize a trainer. trainer = L.Trainer(max_epochs=3) # Auto log all MLflow entities mlflow.pytorch.autolog() # Train the model. with mlflow.start_run() as run: trainer.fit(mnist_model, train_loader) # Fetch the auto logged parameters and metrics. print_auto_logged_info(mlflow.get_run(run_id=run.info.run_id))
-
mlflow.pytorch.
get_default_conda_env
()[source] - Returns
The default Conda environment as a dictionary for MLflow Models produced by calls to
save_model()
andlog_model()
.
import mlflow # Log PyTorch model with mlflow.start_run() as run: mlflow.pytorch.log_model(model, "model", signature=signature) # Fetch the associated conda environment env = mlflow.pytorch.get_default_conda_env() print(f"conda env: {env}")
conda env {'name': 'mlflow-env', 'channels': ['conda-forge'], 'dependencies': ['python=3.8.15', {'pip': ['torch==1.5.1', 'mlflow', 'cloudpickle==1.6.0']}]}
-
mlflow.pytorch.
get_default_pip_requirements
()[source] - Returns
A list of default pip requirements for MLflow Models produced by this flavor. Calls to
save_model()
andlog_model()
produce a pip environment that, at minimum, contains these requirements.
-
mlflow.pytorch.
load_checkpoint
(model_class, run_id=None, epoch=None, global_step=None, kwargs=None)[source] If you enable “checkpoint” in autologging, during pytorch-lightning model training execution, checkpointed models are logged as MLflow artifacts. Using this API, you can load the checkpointed model.
If you want to load the latest checkpoint, set both epoch and global_step to None. If “checkpoint_save_freq” is set to “epoch” in autologging, you can set epoch param to the epoch of the checkpoint to load specific epoch checkpoint. If “checkpoint_save_freq” is set to an integer in autologging, you can set global_step param to the global step of the checkpoint to load specific global step checkpoint. epoch param and global_step can’t be set together.
- Parameters
model_class – The class of the training model, the class should inherit ‘pytorch_lightning.LightningModule’.
run_id – The id of the run which model is logged to. If not provided, current active run is used.
epoch – The epoch of the checkpoint to be loaded, if you set “checkpoint_save_freq” to “epoch”.
global_step – The global step of the checkpoint to be loaded, if you set “checkpoint_save_freq” to an integer.
kwargs – Any extra kwargs needed to init the model.
- Returns
The instance of a pytorch-lightning model restored from the specified checkpoint.
import mlflow mlflow.pytorch.autolog(checkpoint=True) model = MyLightningModuleNet() # A custom-pytorch lightning model train_loader = create_train_dataset_loader() trainer = Trainer() with mlflow.start_run() as run: trainer.fit(model, train_loader) run_id = run.info.run_id # load latest checkpoint model latest_checkpoint_model = mlflow.pytorch.load_checkpoint(MyLightningModuleNet, run_id) # load history checkpoint model logged in second epoch checkpoint_model = mlflow.pytorch.load_checkpoint(MyLightningModuleNet, run_id, epoch=2)
-
mlflow.pytorch.
load_model
(model_uri, dst_path=None, **kwargs)[source] Load a PyTorch model from a local file or a run.
- Parameters
model_uri –
The location, in URI format, of the MLflow model, for example:
/Users/me/path/to/local/model
relative/path/to/local/model
s3://my_bucket/path/to/model
runs:/<mlflow_run_id>/run-relative/path/to/model
models:/<model_name>/<model_version>
models:/<model_name>/<stage>
For more information about supported URI schemes, see Referencing Artifacts.
dst_path – The local filesystem path to which to download the model artifact. This directory must already exist. If unspecified, a local output path will be created.
kwargs – kwargs to pass to
torch.load
method.
- Returns
A PyTorch model.
import torch import mlflow.pytorch model = nn.Linear(1, 1) # Log the model with mlflow.start_run() as run: mlflow.pytorch.log_model(model, "model") # Inference after loading the logged model model_uri = f"runs:/{run.info.run_id}/model" loaded_model = mlflow.pytorch.load_model(model_uri) for x in [4.0, 6.0, 30.0]: X = torch.Tensor([[x]]) y_pred = loaded_model(X) print(f"predict X: {x}, y_pred: {y_pred.data.item():.2f}")
predict X: 4.0, y_pred: 7.57 predict X: 6.0, y_pred: 11.64 predict X: 30.0, y_pred: 60.48
-
mlflow.pytorch.
log_model
(pytorch_model, artifact_path, conda_env=None, code_paths=None, pickle_module=None, registered_model_name=None, signature: mlflow.models.signature.ModelSignature = None, input_example: Union[pandas.core.frame.DataFrame, numpy.ndarray, dict, list, csr_matrix, csc_matrix, str, bytes, tuple] = None, await_registration_for=300, requirements_file=None, extra_files=None, pip_requirements=None, extra_pip_requirements=None, metadata=None, **kwargs)[source] Log a PyTorch model as an MLflow artifact for the current run.
Warning
Log the model with a signature to avoid inference errors. If the model is logged without a signature, the MLflow Model Server relies on the default inferred data type from NumPy. However, PyTorch often expects different defaults, particularly when parsing floats. You must include the signature to ensure that the model is logged with the correct data type so that the MLflow model server can correctly provide valid input.
- Parameters
pytorch_model –
PyTorch model to be saved. Can be either an eager model (subclass of
torch.nn.Module
) or scripted model prepared viatorch.jit.script
ortorch.jit.trace
.The model accept a single
torch.FloatTensor
as input and produce a single output tensor.If saving an eager model, any code dependencies of the model’s class, including the class definition itself, should be included in one of the following locations:
The package(s) listed in the model’s Conda environment, specified by the
conda_env
parameter.One or more of the files specified by the
code_paths
parameter.
artifact_path – Run-relative artifact path.
conda_env –
Either a dictionary representation of a Conda environment or the path to a conda environment yaml file. If provided, this describes the environment this model should be run in. At a minimum, it should specify the dependencies contained in
get_default_conda_env()
. IfNone
, a conda environment with pip requirements inferred bymlflow.models.infer_pip_requirements()
is added to the model. If the requirement inference fails, it falls back to usingget_default_pip_requirements()
. pip requirements fromconda_env
are written to a piprequirements.txt
file and the full conda environment is written toconda.yaml
. The following is an example dictionary representation of a conda environment:{ "name": "mlflow-env", "channels": ["conda-forge"], "dependencies": [ "python=3.8.15", { "pip": [ "torch==x.y.z" ], }, ], }
code_paths –
A list of local filesystem paths to Python file dependencies (or directories containing file dependencies). These files are prepended to the system path when the model is loaded. Files declared as dependencies for a given model should have relative imports declared from a common root path if multiple files are defined with import dependencies between them to avoid import errors when loading the model.
You can leave
code_paths
argument unset but setinfer_code_paths
toTrue
to let MLflow infer the model code paths. Seeinfer_code_paths
argument doc for details.For a detailed explanation of
code_paths
functionality, recommended usage patterns and limitations, see the code_paths usage guide.pickle_module – The module that PyTorch should use to serialize (“pickle”) the specified
pytorch_model
. This is passed as thepickle_module
parameter totorch.save()
. By default, this module is also used to deserialize (“unpickle”) the PyTorch model at load time.registered_model_name – If given, create a model version under
registered_model_name
, also create a registered model if one with the given name does not exist.signature –
an instance of the
ModelSignature
class that describes the model’s inputs and outputs. If not specified but aninput_example
is supplied, a signature will be automatically inferred based on the supplied input example and model. To disable automatic signature inference when providing an input example, setsignature
toFalse
. To manually infer a model signature, callinfer_signature()
on datasets with valid model inputs, such as a training dataset with the target column omitted, and valid model outputs, like model predictions made on the training dataset, for example:from mlflow.models import infer_signature train = df.drop_column("target_label") predictions = ... # compute model predictions signature = infer_signature(train, predictions)
input_example – one or several instances of valid model input. The input example is used as a hint of what data to feed the model. It will be converted to a Pandas DataFrame and then serialized to json using the Pandas split-oriented format, or a numpy array where the example will be serialized to json by converting it to a list. Bytes are base64-encoded. When the
signature
parameter isNone
, the input example is used to infer a model signature.await_registration_for – Number of seconds to wait for the model version to finish being created and is in
READY
status. By default, the function waits for five minutes. Specify 0 or None to skip waiting.requirements_file –
Warning
requirements_file
has been deprecated. Please usepip_requirements
instead.A string containing the path to requirements file. Remote URIs are resolved to absolute filesystem paths. For example, consider the following
requirements_file
string:requirements_file = "s3://my-bucket/path/to/my_file"
In this case, the
"my_file"
requirements file is downloaded from S3. IfNone
, no requirements file is added to the model.extra_files –
A list containing the paths to corresponding extra files, if
None
, no extra files are added to the model. Remote URIs are resolved to absolute filesystem paths. For example, consider the followingextra_files
list:extra_files = ["s3://my-bucket/path/to/my_file1", "s3://my-bucket/path/to/my_file2"]
In this case, the
"my_file1 & my_file2"
extra file is downloaded from S3.pip_requirements – Either an iterable of pip requirement strings (e.g.
["torch", "-r requirements.txt", "-c constraints.txt"]
) or the string path to a pip requirements file on the local filesystem (e.g."requirements.txt"
). If provided, this describes the environment this model should be run in. IfNone
, a default list of requirements is inferred bymlflow.models.infer_pip_requirements()
from the current software environment. If the requirement inference fails, it falls back to usingget_default_pip_requirements()
. Both requirements and constraints are automatically parsed and written torequirements.txt
andconstraints.txt
files, respectively, and stored as part of the model. Requirements are also written to thepip
section of the model’s conda environment (conda.yaml
) file.extra_pip_requirements –
Either an iterable of pip requirement strings (e.g.
["pandas", "-r requirements.txt", "-c constraints.txt"]
) or the string path to a pip requirements file on the local filesystem (e.g."requirements.txt"
). If provided, this describes additional pip requirements that are appended to a default set of pip requirements generated automatically based on the user’s current software environment. Both requirements and constraints are automatically parsed and written torequirements.txt
andconstraints.txt
files, respectively, and stored as part of the model. Requirements are also written to thepip
section of the model’s conda environment (conda.yaml
) file.Warning
The following arguments can’t be specified at the same time:
conda_env
pip_requirements
extra_pip_requirements
This example demonstrates how to specify pip requirements using
pip_requirements
andextra_pip_requirements
.metadata – Custom metadata dictionary passed to the model and stored in the MLmodel file.
kwargs – kwargs to pass to
torch.save
method.
- Returns
A
ModelInfo
instance that contains the metadata of the logged model.
import numpy as np import torch import mlflow from mlflow import MlflowClient from mlflow.models import infer_signature # Define model, loss, and optimizer model = nn.Linear(1, 1) criterion = torch.nn.MSELoss() optimizer = torch.optim.SGD(model.parameters(), lr=0.001) # Create training data with relationship y = 2X X = torch.arange(1.0, 26.0).reshape(-1, 1) y = X * 2 # Training loop epochs = 250 for epoch in range(epochs): # Forward pass: Compute predicted y by passing X to the model y_pred = model(X) # Compute the loss loss = criterion(y_pred, y) # Zero gradients, perform a backward pass, and update the weights. optimizer.zero_grad() loss.backward() optimizer.step() # Create model signature signature = infer_signature(X.numpy(), model(X).detach().numpy()) # Log the model with mlflow.start_run() as run: mlflow.pytorch.log_model(model, "model") # convert to scripted model and log the model scripted_pytorch_model = torch.jit.script(model) mlflow.pytorch.log_model(scripted_pytorch_model, "scripted_model") # Fetch the logged model artifacts print(f"run_id: {run.info.run_id}") for artifact_path in ["model/data", "scripted_model/data"]: artifacts = [ f.path for f in MlflowClient().list_artifacts(run.info.run_id, artifact_path) ] print(f"artifacts: {artifacts}")
run_id: 1a1ec9e413ce48e9abf9aec20efd6f71 artifacts: ['model/data/model.pth', 'model/data/pickle_module_info.txt'] artifacts: ['scripted_model/data/model.pth', 'scripted_model/data/pickle_module_info.txt']
-
mlflow.pytorch.
save_model
(pytorch_model, path, conda_env=None, mlflow_model=None, code_paths=None, pickle_module=None, signature: mlflow.models.signature.ModelSignature = None, input_example: Union[pandas.core.frame.DataFrame, numpy.ndarray, dict, list, csr_matrix, csc_matrix, str, bytes, tuple] = None, requirements_file=None, extra_files=None, pip_requirements=None, extra_pip_requirements=None, metadata=None, **kwargs)[source] Save a PyTorch model to a path on the local file system.
- Parameters
pytorch_model –
PyTorch model to be saved. Can be either an eager model (subclass of
torch.nn.Module
) or a scripted model prepared viatorch.jit.script
ortorch.jit.trace
.To save an eager model, any code dependencies of the model’s class, including the class definition itself, should be included in one of the following locations:
The package(s) listed in the model’s Conda environment, specified by the
conda_env
parameter.One or more of the files specified by the
code_paths
parameter.
path – Local path where the model is to be saved.
conda_env –
Either a dictionary representation of a Conda environment or the path to a conda environment yaml file. If provided, this describes the environment this model should be run in. At a minimum, it should specify the dependencies contained in
get_default_conda_env()
. IfNone
, a conda environment with pip requirements inferred bymlflow.models.infer_pip_requirements()
is added to the model. If the requirement inference fails, it falls back to usingget_default_pip_requirements()
. pip requirements fromconda_env
are written to a piprequirements.txt
file and the full conda environment is written toconda.yaml
. The following is an example dictionary representation of a conda environment:{ "name": "mlflow-env", "channels": ["conda-forge"], "dependencies": [ "python=3.8.15", { "pip": [ "torch==x.y.z" ], }, ], }
mlflow_model –
mlflow.models.Model
this flavor is being added to.code_paths –
A list of local filesystem paths to Python file dependencies (or directories containing file dependencies). These files are prepended to the system path when the model is loaded. Files declared as dependencies for a given model should have relative imports declared from a common root path if multiple files are defined with import dependencies between them to avoid import errors when loading the model.
You can leave
code_paths
argument unset but setinfer_code_paths
toTrue
to let MLflow infer the model code paths. Seeinfer_code_paths
argument doc for details.For a detailed explanation of
code_paths
functionality, recommended usage patterns and limitations, see the code_paths usage guide.pickle_module – The module that PyTorch should use to serialize (“pickle”) the specified
pytorch_model
. This is passed as thepickle_module
parameter totorch.save()
. By default, this module is also used to deserialize (“unpickle”) the model at loading time.signature –
an instance of the
ModelSignature
class that describes the model’s inputs and outputs. If not specified but aninput_example
is supplied, a signature will be automatically inferred based on the supplied input example and model. To disable automatic signature inference when providing an input example, setsignature
toFalse
. To manually infer a model signature, callinfer_signature()
on datasets with valid model inputs, such as a training dataset with the target column omitted, and valid model outputs, like model predictions made on the training dataset, for example:from mlflow.models import infer_signature train = df.drop_column("target_label") predictions = ... # compute model predictions signature = infer_signature(train, predictions)
input_example – one or several instances of valid model input. The input example is used as a hint of what data to feed the model. It will be converted to a Pandas DataFrame and then serialized to json using the Pandas split-oriented format, or a numpy array where the example will be serialized to json by converting it to a list. Bytes are base64-encoded. When the
signature
parameter isNone
, the input example is used to infer a model signature.requirements_file –
Warning
requirements_file
has been deprecated. Please usepip_requirements
instead.A string containing the path to requirements file. Remote URIs are resolved to absolute filesystem paths. For example, consider the following
requirements_file
string:requirements_file = "s3://my-bucket/path/to/my_file"
In this case, the
"my_file"
requirements file is downloaded from S3. IfNone
, no requirements file is added to the model.extra_files –
A list containing the paths to corresponding extra files. Remote URIs are resolved to absolute filesystem paths. For example, consider the following
extra_files
list -extra_files = [“s3://my-bucket/path/to/my_file1”, “s3://my-bucket/path/to/my_file2”]
In this case, the
"my_file1 & my_file2"
extra file is downloaded from S3.If
None
, no extra files are added to the model.pip_requirements – Either an iterable of pip requirement strings (e.g.
["torch", "-r requirements.txt", "-c constraints.txt"]
) or the string path to a pip requirements file on the local filesystem (e.g."requirements.txt"
). If provided, this describes the environment this model should be run in. IfNone
, a default list of requirements is inferred bymlflow.models.infer_pip_requirements()
from the current software environment. If the requirement inference fails, it falls back to usingget_default_pip_requirements()
. Both requirements and constraints are automatically parsed and written torequirements.txt
andconstraints.txt
files, respectively, and stored as part of the model. Requirements are also written to thepip
section of the model’s conda environment (conda.yaml
) file.extra_pip_requirements –
Either an iterable of pip requirement strings (e.g.
["pandas", "-r requirements.txt", "-c constraints.txt"]
) or the string path to a pip requirements file on the local filesystem (e.g."requirements.txt"
). If provided, this describes additional pip requirements that are appended to a default set of pip requirements generated automatically based on the user’s current software environment. Both requirements and constraints are automatically parsed and written torequirements.txt
andconstraints.txt
files, respectively, and stored as part of the model. Requirements are also written to thepip
section of the model’s conda environment (conda.yaml
) file.Warning
The following arguments can’t be specified at the same time:
conda_env
pip_requirements
extra_pip_requirements
This example demonstrates how to specify pip requirements using
pip_requirements
andextra_pip_requirements
.metadata – Custom metadata dictionary passed to the model and stored in the MLmodel file.
kwargs – kwargs to pass to
torch.save
method.
import os import mlflow import torch model = nn.Linear(1, 1) # Save PyTorch models to current working directory with mlflow.start_run() as run: mlflow.pytorch.save_model(model, "model") # Convert to a scripted model and save it scripted_pytorch_model = torch.jit.script(model) mlflow.pytorch.save_model(scripted_pytorch_model, "scripted_model") # Load each saved model for inference for model_path in ["model", "scripted_model"]: model_uri = f"{os.getcwd()}/{model_path}" loaded_model = mlflow.pytorch.load_model(model_uri) print(f"Loaded {model_path}:") for x in [6.0, 8.0, 12.0, 30.0]: X = torch.Tensor([[x]]) y_pred = loaded_model(X) print(f"predict X: {x}, y_pred: {y_pred.data.item():.2f}") print("--")
Loaded model: predict X: 6.0, y_pred: 11.90 predict X: 8.0, y_pred: 15.92 predict X: 12.0, y_pred: 23.96 predict X: 30.0, y_pred: 60.13 -- Loaded scripted_model: predict X: 6.0, y_pred: 11.90 predict X: 8.0, y_pred: 15.92 predict X: 12.0, y_pred: 23.96 predict X: 30.0, y_pred: 60.13