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# 

# Licensed to the Apache Software Foundation (ASF) under one or more 

# contributor license agreements. See the NOTICE file distributed with 

# this work for additional information regarding copyright ownership. 

# The ASF licenses this file to You under the Apache License, Version 2.0 

# (the "License"); you may not use this file except in compliance with 

# the License. You may obtain a copy of the License at 

# 

# http://www.apache.org/licenses/LICENSE-2.0 

# 

# Unless required by applicable law or agreed to in writing, software 

# distributed under the License is distributed on an "AS IS" BASIS, 

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 

# See the License for the specific language governing permissions and 

# limitations under the License. 

# 

 

import json 

import os 

import time 

import uuid 

 

from pyspark import SparkContext, since 

from pyspark.ml.common import inherit_doc 

from pyspark.sql import SparkSession 

from pyspark.util import VersionUtils 

 

 

def _jvm(): 

""" 

Returns the JVM view associated with SparkContext. Must be called 

after SparkContext is initialized. 

""" 

jvm = SparkContext._jvm 

35 ↛ 38line 35 didn't jump to line 38, because the condition on line 35 was never false if jvm: 

return jvm 

else: 

raise AttributeError("Cannot load _jvm from SparkContext. Is SparkContext initialized?") 

 

 

class Identifiable(object): 

""" 

Object with a unique ID. 

""" 

 

def __init__(self): 

#: A unique id for the object. 

self.uid = self._randomUID() 

 

def __repr__(self): 

return self.uid 

 

@classmethod 

def _randomUID(cls): 

""" 

Generate a unique string id for the object. The default implementation 

concatenates the class name, "_", and 12 random hex chars. 

""" 

return str(cls.__name__ + "_" + uuid.uuid4().hex[-12:]) 

 

 

@inherit_doc 

class BaseReadWrite(object): 

""" 

Base class for MLWriter and MLReader. Stores information about the SparkContext 

and SparkSession. 

 

.. versionadded:: 2.3.0 

""" 

 

def __init__(self): 

self._sparkSession = None 

 

def session(self, sparkSession): 

""" 

Sets the Spark Session to use for saving/loading. 

""" 

self._sparkSession = sparkSession 

return self 

 

@property 

def sparkSession(self): 

""" 

Returns the user-specified Spark Session or the default. 

""" 

if self._sparkSession is None: 

self._sparkSession = SparkSession.builder.getOrCreate() 

return self._sparkSession 

 

@property 

def sc(self): 

""" 

Returns the underlying `SparkContext`. 

""" 

return self.sparkSession.sparkContext 

 

 

@inherit_doc 

class MLWriter(BaseReadWrite): 

""" 

Utility class that can save ML instances. 

 

.. versionadded:: 2.0.0 

""" 

 

def __init__(self): 

super(MLWriter, self).__init__() 

self.shouldOverwrite = False 

self.optionMap = {} 

 

def _handleOverwrite(self, path): 

from pyspark.ml.wrapper import JavaWrapper 

 

_java_obj = JavaWrapper._new_java_obj("org.apache.spark.ml.util.FileSystemOverwrite") 

wrapper = JavaWrapper(_java_obj) 

wrapper._call_java("handleOverwrite", path, True, self.sparkSession._jsparkSession) 

 

def save(self, path): 

"""Save the ML instance to the input path.""" 

if self.shouldOverwrite: 

self._handleOverwrite(path) 

self.saveImpl(path) 

 

def saveImpl(self, path): 

""" 

save() handles overwriting and then calls this method. Subclasses should override this 

method to implement the actual saving of the instance. 

""" 

raise NotImplementedError("MLWriter is not yet implemented for type: %s" % type(self)) 

 

def overwrite(self): 

"""Overwrites if the output path already exists.""" 

self.shouldOverwrite = True 

return self 

 

def option(self, key, value): 

""" 

Adds an option to the underlying MLWriter. See the documentation for the specific model's 

writer for possible options. The option name (key) is case-insensitive. 

""" 

self.optionMap[key.lower()] = str(value) 

return self 

 

 

@inherit_doc 

class GeneralMLWriter(MLWriter): 

""" 

Utility class that can save ML instances in different formats. 

 

.. versionadded:: 2.4.0 

""" 

 

def format(self, source): 

""" 

Specifies the format of ML export ("pmml", "internal", or the fully qualified class 

name for export). 

""" 

self.source = source 

return self 

 

 

@inherit_doc 

class JavaMLWriter(MLWriter): 

""" 

(Private) Specialization of :py:class:`MLWriter` for :py:class:`JavaParams` types 

""" 

 

def __init__(self, instance): 

super(JavaMLWriter, self).__init__() 

_java_obj = instance._to_java() 

self._jwrite = _java_obj.write() 

 

def save(self, path): 

"""Save the ML instance to the input path.""" 

175 ↛ 176line 175 didn't jump to line 176, because the condition on line 175 was never true if not isinstance(path, str): 

raise TypeError("path should be a string, got type %s" % type(path)) 

self._jwrite.save(path) 

 

def overwrite(self): 

"""Overwrites if the output path already exists.""" 

self._jwrite.overwrite() 

return self 

 

def option(self, key, value): 

self._jwrite.option(key, value) 

return self 

 

def session(self, sparkSession): 

"""Sets the Spark Session to use for saving.""" 

self._jwrite.session(sparkSession._jsparkSession) 

return self 

 

 

@inherit_doc 

class GeneralJavaMLWriter(JavaMLWriter): 

""" 

(Private) Specialization of :py:class:`GeneralMLWriter` for :py:class:`JavaParams` types 

""" 

 

def __init__(self, instance): 

super(GeneralJavaMLWriter, self).__init__(instance) 

 

def format(self, source): 

""" 

Specifies the format of ML export ("pmml", "internal", or the fully qualified class 

name for export). 

""" 

self._jwrite.format(source) 

return self 

 

 

@inherit_doc 

class MLWritable(object): 

""" 

Mixin for ML instances that provide :py:class:`MLWriter`. 

 

.. versionadded:: 2.0.0 

""" 

 

def write(self): 

"""Returns an MLWriter instance for this ML instance.""" 

raise NotImplementedError("MLWritable is not yet implemented for type: %r" % type(self)) 

 

def save(self, path): 

"""Save this ML instance to the given path, a shortcut of 'write().save(path)'.""" 

self.write().save(path) 

 

 

@inherit_doc 

class JavaMLWritable(MLWritable): 

""" 

(Private) Mixin for ML instances that provide :py:class:`JavaMLWriter`. 

""" 

 

def write(self): 

"""Returns an MLWriter instance for this ML instance.""" 

return JavaMLWriter(self) 

 

 

@inherit_doc 

class GeneralJavaMLWritable(JavaMLWritable): 

""" 

(Private) Mixin for ML instances that provide :py:class:`GeneralJavaMLWriter`. 

""" 

 

def write(self): 

"""Returns an GeneralMLWriter instance for this ML instance.""" 

return GeneralJavaMLWriter(self) 

 

 

@inherit_doc 

class MLReader(BaseReadWrite): 

""" 

Utility class that can load ML instances. 

 

.. versionadded:: 2.0.0 

""" 

 

def __init__(self): 

super(MLReader, self).__init__() 

 

def load(self, path): 

"""Load the ML instance from the input path.""" 

raise NotImplementedError("MLReader is not yet implemented for type: %s" % type(self)) 

 

 

@inherit_doc 

class JavaMLReader(MLReader): 

""" 

(Private) Specialization of :py:class:`MLReader` for :py:class:`JavaParams` types 

""" 

 

def __init__(self, clazz): 

super(JavaMLReader, self).__init__() 

self._clazz = clazz 

self._jread = self._load_java_obj(clazz).read() 

 

def load(self, path): 

"""Load the ML instance from the input path.""" 

280 ↛ 281line 280 didn't jump to line 281, because the condition on line 280 was never true if not isinstance(path, str): 

raise TypeError("path should be a string, got type %s" % type(path)) 

java_obj = self._jread.load(path) 

283 ↛ 284line 283 didn't jump to line 284, because the condition on line 283 was never true if not hasattr(self._clazz, "_from_java"): 

raise NotImplementedError("This Java ML type cannot be loaded into Python currently: %r" 

% self._clazz) 

return self._clazz._from_java(java_obj) 

 

def session(self, sparkSession): 

"""Sets the Spark Session to use for loading.""" 

self._jread.session(sparkSession._jsparkSession) 

return self 

 

@classmethod 

def _java_loader_class(cls, clazz): 

""" 

Returns the full class name of the Java ML instance. The default 

implementation replaces "pyspark" by "org.apache.spark" in 

the Python full class name. 

""" 

java_package = clazz.__module__.replace("pyspark", "org.apache.spark") 

if clazz.__name__ in ("Pipeline", "PipelineModel"): 

# Remove the last package name "pipeline" for Pipeline and PipelineModel. 

java_package = ".".join(java_package.split(".")[0:-1]) 

return java_package + "." + clazz.__name__ 

 

@classmethod 

def _load_java_obj(cls, clazz): 

"""Load the peer Java object of the ML instance.""" 

java_class = cls._java_loader_class(clazz) 

java_obj = _jvm() 

for name in java_class.split("."): 

java_obj = getattr(java_obj, name) 

return java_obj 

 

 

@inherit_doc 

class MLReadable(object): 

""" 

Mixin for instances that provide :py:class:`MLReader`. 

 

.. versionadded:: 2.0.0 

""" 

 

@classmethod 

def read(cls): 

"""Returns an MLReader instance for this class.""" 

raise NotImplementedError("MLReadable.read() not implemented for type: %r" % cls) 

 

@classmethod 

def load(cls, path): 

"""Reads an ML instance from the input path, a shortcut of `read().load(path)`.""" 

return cls.read().load(path) 

 

 

@inherit_doc 

class JavaMLReadable(MLReadable): 

""" 

(Private) Mixin for instances that provide JavaMLReader. 

""" 

 

@classmethod 

def read(cls): 

"""Returns an MLReader instance for this class.""" 

return JavaMLReader(cls) 

 

 

@inherit_doc 

class DefaultParamsWritable(MLWritable): 

""" 

Helper trait for making simple :py:class:`Params` types writable. If a :py:class:`Params` 

class stores all data as :py:class:`Param` values, then extending this trait will provide 

a default implementation of writing saved instances of the class. 

This only handles simple :py:class:`Param` types; e.g., it will not handle 

:py:class:`pyspark.sql.DataFrame`. See :py:class:`DefaultParamsReadable`, the counterpart 

to this class. 

 

.. versionadded:: 2.3.0 

""" 

 

def write(self): 

"""Returns a DefaultParamsWriter instance for this class.""" 

from pyspark.ml.param import Params 

 

364 ↛ 367line 364 didn't jump to line 367, because the condition on line 364 was never false if isinstance(self, Params): 

return DefaultParamsWriter(self) 

else: 

raise TypeError("Cannot use DefautParamsWritable with type %s because it does not " + 

" extend Params.", type(self)) 

 

 

@inherit_doc 

class DefaultParamsWriter(MLWriter): 

""" 

Specialization of :py:class:`MLWriter` for :py:class:`Params` types 

 

Class for writing Estimators and Transformers whose parameters are JSON-serializable. 

 

.. versionadded:: 2.3.0 

""" 

 

def __init__(self, instance): 

super(DefaultParamsWriter, self).__init__() 

self.instance = instance 

 

def saveImpl(self, path): 

DefaultParamsWriter.saveMetadata(self.instance, path, self.sc) 

 

@staticmethod 

def extractJsonParams(instance, skipParams): 

paramMap = instance.extractParamMap() 

jsonParams = {param.name: value for param, value in paramMap.items() 

if param.name not in skipParams} 

return jsonParams 

 

@staticmethod 

def saveMetadata(instance, path, sc, extraMetadata=None, paramMap=None): 

""" 

Saves metadata + Params to: path + "/metadata" 

 

- class 

- timestamp 

- sparkVersion 

- uid 

- paramMap 

- defaultParamMap (since 2.4.0) 

- (optionally, extra metadata) 

 

Parameters 

---------- 

extraMetadata : dict, optional 

Extra metadata to be saved at same level as uid, paramMap, etc. 

paramMap : dict, optional 

If given, this is saved in the "paramMap" field. 

""" 

metadataPath = os.path.join(path, "metadata") 

metadataJson = DefaultParamsWriter._get_metadata_to_save(instance, 

sc, 

extraMetadata, 

paramMap) 

sc.parallelize([metadataJson], 1).saveAsTextFile(metadataPath) 

 

@staticmethod 

def _get_metadata_to_save(instance, sc, extraMetadata=None, paramMap=None): 

""" 

Helper for :py:meth:`DefaultParamsWriter.saveMetadata` which extracts the JSON to save. 

This is useful for ensemble models which need to save metadata for many sub-models. 

 

Notes 

----- 

See :py:meth:`DefaultParamsWriter.saveMetadata` for details on what this includes. 

""" 

uid = instance.uid 

cls = instance.__module__ + '.' + instance.__class__.__name__ 

 

# User-supplied param values 

params = instance._paramMap 

jsonParams = {} 

if paramMap is not None: 

jsonParams = paramMap 

else: 

for p in params: 

jsonParams[p.name] = params[p] 

 

# Default param values 

jsonDefaultParams = {} 

for p in instance._defaultParamMap: 

jsonDefaultParams[p.name] = instance._defaultParamMap[p] 

 

basicMetadata = {"class": cls, "timestamp": int(round(time.time() * 1000)), 

"sparkVersion": sc.version, "uid": uid, "paramMap": jsonParams, 

"defaultParamMap": jsonDefaultParams} 

if extraMetadata is not None: 

basicMetadata.update(extraMetadata) 

return json.dumps(basicMetadata, separators=[',', ':']) 

 

 

@inherit_doc 

class DefaultParamsReadable(MLReadable): 

""" 

Helper trait for making simple :py:class:`Params` types readable. 

If a :py:class:`Params` class stores all data as :py:class:`Param` values, 

then extending this trait will provide a default implementation of reading saved 

instances of the class. This only handles simple :py:class:`Param` types; 

e.g., it will not handle :py:class:`pyspark.sql.DataFrame`. See 

:py:class:`DefaultParamsWritable`, the counterpart to this class. 

 

.. versionadded:: 2.3.0 

""" 

 

@classmethod 

def read(cls): 

"""Returns a DefaultParamsReader instance for this class.""" 

return DefaultParamsReader(cls) 

 

 

@inherit_doc 

class DefaultParamsReader(MLReader): 

""" 

Specialization of :py:class:`MLReader` for :py:class:`Params` types 

 

Default :py:class:`MLReader` implementation for transformers and estimators that 

contain basic (json-serializable) params and no data. This will not handle 

more complex params or types with data (e.g., models with coefficients). 

 

.. versionadded:: 2.3.0 

""" 

 

def __init__(self, cls): 

super(DefaultParamsReader, self).__init__() 

self.cls = cls 

 

@staticmethod 

def __get_class(clazz): 

""" 

Loads Python class from its name. 

""" 

parts = clazz.split('.') 

module = ".".join(parts[:-1]) 

m = __import__(module) 

for comp in parts[1:]: 

m = getattr(m, comp) 

return m 

 

def load(self, path): 

metadata = DefaultParamsReader.loadMetadata(path, self.sc) 

py_type = DefaultParamsReader.__get_class(metadata['class']) 

instance = py_type() 

instance._resetUid(metadata['uid']) 

DefaultParamsReader.getAndSetParams(instance, metadata) 

return instance 

 

@staticmethod 

def loadMetadata(path, sc, expectedClassName=""): 

""" 

Load metadata saved using :py:meth:`DefaultParamsWriter.saveMetadata` 

 

Parameters 

---------- 

path : str 

sc : :py:class:`pyspark.SparkContext` 

expectedClassName : str, optional 

If non empty, this is checked against the loaded metadata. 

""" 

metadataPath = os.path.join(path, "metadata") 

metadataStr = sc.textFile(metadataPath, 1).first() 

loadedVals = DefaultParamsReader._parseMetaData(metadataStr, expectedClassName) 

return loadedVals 

 

@staticmethod 

def _parseMetaData(metadataStr, expectedClassName=""): 

""" 

Parse metadata JSON string produced by :py:meth`DefaultParamsWriter._get_metadata_to_save`. 

This is a helper function for :py:meth:`DefaultParamsReader.loadMetadata`. 

 

Parameters 

---------- 

metadataStr : str 

JSON string of metadata 

expectedClassName : str, optional 

If non empty, this is checked against the loaded metadata. 

""" 

metadata = json.loads(metadataStr) 

className = metadata['class'] 

544 ↛ 545line 544 didn't jump to line 545, because the condition on line 544 was never true if len(expectedClassName) > 0: 

assert className == expectedClassName, "Error loading metadata: Expected " + \ 

"class name {} but found class name {}".format(expectedClassName, className) 

return metadata 

 

@staticmethod 

def getAndSetParams(instance, metadata, skipParams=None): 

""" 

Extract Params from metadata, and set them in the instance. 

""" 

# Set user-supplied param values 

for paramName in metadata['paramMap']: 

param = instance.getParam(paramName) 

if skipParams is None or paramName not in skipParams: 

paramValue = metadata['paramMap'][paramName] 

instance.set(param, paramValue) 

 

# Set default param values 

majorAndMinorVersions = VersionUtils.majorMinorVersion(metadata['sparkVersion']) 

major = majorAndMinorVersions[0] 

minor = majorAndMinorVersions[1] 

 

# For metadata file prior to Spark 2.4, there is no default section. 

if major > 2 or (major == 2 and minor >= 4): 

assert 'defaultParamMap' in metadata, "Error loading metadata: Expected " + \ 

"`defaultParamMap` section not found" 

 

for paramName in metadata['defaultParamMap']: 

paramValue = metadata['defaultParamMap'][paramName] 

instance._setDefault(**{paramName: paramValue}) 

 

@staticmethod 

def isPythonParamsInstance(metadata): 

return metadata['class'].startswith('pyspark.ml.') 

 

@staticmethod 

def loadParamsInstance(path, sc): 

""" 

Load a :py:class:`Params` instance from the given path, and return it. 

This assumes the instance inherits from :py:class:`MLReadable`. 

""" 

metadata = DefaultParamsReader.loadMetadata(path, sc) 

if DefaultParamsReader.isPythonParamsInstance(metadata): 

pythonClassName = metadata['class'] 

else: 

pythonClassName = metadata['class'].replace("org.apache.spark", "pyspark") 

py_type = DefaultParamsReader.__get_class(pythonClassName) 

instance = py_type.load(path) 

return instance 

 

 

@inherit_doc 

class HasTrainingSummary(object): 

""" 

Base class for models that provides Training summary. 

 

.. versionadded:: 3.0.0 

""" 

 

@property 

@since("2.1.0") 

def hasSummary(self): 

""" 

Indicates whether a training summary exists for this model 

instance. 

""" 

return self._call_java("hasSummary") 

 

@property 

@since("2.1.0") 

def summary(self): 

""" 

Gets summary of the model trained on the training set. An exception is thrown if 

no summary exists. 

""" 

return (self._call_java("summary")) 

 

 

class MetaAlgorithmReadWrite: 

 

@staticmethod 

def isMetaEstimator(pyInstance): 

from pyspark.ml import Estimator, Pipeline 

from pyspark.ml.tuning import _ValidatorParams 

from pyspark.ml.classification import OneVsRest 

return isinstance(pyInstance, Pipeline) or isinstance(pyInstance, OneVsRest) or \ 

(isinstance(pyInstance, Estimator) and isinstance(pyInstance, _ValidatorParams)) 

 

@staticmethod 

def getAllNestedStages(pyInstance): 

from pyspark.ml import Pipeline, PipelineModel 

from pyspark.ml.tuning import _ValidatorParams 

from pyspark.ml.classification import OneVsRest, OneVsRestModel 

 

# TODO: We need to handle `RFormulaModel.pipelineModel` here after Pyspark RFormulaModel 

# support pipelineModel property. 

if isinstance(pyInstance, Pipeline): 

pySubStages = pyInstance.getStages() 

elif isinstance(pyInstance, PipelineModel): 

pySubStages = pyInstance.stages 

644 ↛ 645line 644 didn't jump to line 645, because the condition on line 644 was never true elif isinstance(pyInstance, _ValidatorParams): 

raise ValueError('PySpark does not support nested validator.') 

elif isinstance(pyInstance, OneVsRest): 

pySubStages = [pyInstance.getClassifier()] 

elif isinstance(pyInstance, OneVsRestModel): 

pySubStages = [pyInstance.getClassifier()] + pyInstance.models 

else: 

pySubStages = [] 

 

nestedStages = [] 

for pySubStage in pySubStages: 

nestedStages.extend(MetaAlgorithmReadWrite.getAllNestedStages(pySubStage)) 

 

return [pyInstance] + nestedStages 

 

@staticmethod 

def getUidMap(instance): 

nestedStages = MetaAlgorithmReadWrite.getAllNestedStages(instance) 

uidMap = {stage.uid: stage for stage in nestedStages} 

663 ↛ 664line 663 didn't jump to line 664, because the condition on line 663 was never true if len(nestedStages) != len(uidMap): 

raise RuntimeError(f'{instance.__class__.__module__}.{instance.__class__.__name__}' 

f'.load found a compound estimator with stages with duplicate ' 

f'UIDs. List of UIDs: {list(uidMap.keys())}.') 

return uidMap