ModelValidator TFX 流水线组件（已弃用）

ModelValidator 用于检查模型是否足以用于生产环境。我们仍然认为验证是有用的，但是由于模型 Evaluator 已经计算了要验证的所有指标，因此我们决定将两者融合，这样您就不必重复计算。

尽管我们已弃用 ModelValidator 并且不建议使用它，不过，如果您需要维护现有的 ModelValidator 组件，则示例配置如下：

import tfx
import tensorflow_model_analysis as tfma
from tfx.components.model_validator.component import ModelValidator

...

model_validator = ModelValidator(
      examples=example_gen.outputs['output_data'],
      model=trainer.outputs['model'])

对于想要将配置迁移到 Evaluator 的用户，Evaluator 的类似配置如下所示：

from tfx import components
import tensorflow_model_analysis as tfma

...

eval_config = tfma.EvalConfig(
    model_specs=[
        # This assumes a serving model with signature 'serving_default'. If
        # using estimator based EvalSavedModel, add signature_name: 'eval' and
        # remove the label_key.
        tfma.ModelSpec(label_key='<label_key>')
    ],
    metrics_specs=[
        tfma.MetricsSpec(
            # The metrics added here are in addition to those saved with the
            # model (assuming either a keras model or EvalSavedModel is used).
            # Any metrics added into the saved model (for example using
            # model.compile(..., metrics=[...]), etc) will be computed
            # automatically.
            metrics=[
                tfma.MetricConfig(class_name='ExampleCount'),
                tfma.MetricConfig(
                    class_name='BinaryAccuracy',
                    threshold=tfma.MetricThreshold(
                        value_threshold=tfma.GenericValueThreshold(
                            lower_bound={'value': 0.5}),
                        change_threshold=tfma.GenericChangeThreshold(
                            direction=tfma.MetricDirection.HIGHER_IS_BETTER,
                            absolute={'value': -1e-10})))
            ]
        )
    ],
    slicing_specs=[
        # An empty slice spec means the overall slice, i.e. the whole dataset.
        tfma.SlicingSpec(),
        # Data can be sliced along a feature column. In this case, data is
        # sliced along feature column trip_start_hour.
        tfma.SlicingSpec(feature_keys=['trip_start_hour'])
    ])

model_resolver = ResolverNode(
      instance_name='latest_blessed_model_resolver',
      resolver_class=latest_blessed_model_resolver.LatestBlessedModelResolver,
      model=Channel(type=Model),
      model_blessing=Channel(type=ModelBlessing))

model_analyzer = components.Evaluator(
      examples=examples_gen.outputs['examples'],
      model=trainer.outputs['model'],
      baseline_model=model_resolver.outputs['model'],
      # Change threshold will be ignored if there is no baseline (first run).
      eval_config=eval_config)