snowpark-checkpoints-validators 0.4.0

Migration tools for Snowpark

snowpark-checkpoints-validators

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This package is on Public Preview.

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snowpark-checkpoints-validators is a package designed to validate Snowpark DataFrames against predefined schemas and checkpoints. This package ensures data integrity and consistency by performing schema and data validation checks at various stages of a Snowpark pipeline.

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Install the library

pip install snowpark-checkpoints-validators

This package requires PySpark to be installed in the same environment. If you do not have it, you can install PySpark alongside Snowpark Checkpoints by running the following command:

pip install "snowpark-checkpoints-validators[pyspark]"

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Features

• Validate Snowpark DataFrames against predefined Pandera schemas.
• Perform custom checks and skip specific checks as needed.
• Generate validation results and log them for further analysis.
• Support for sampling strategies to validate large datasets efficiently.
• Integration with PySpark for cross-validation between Snowpark and PySpark DataFrames.

Functionalities

Validate DataFrame Schema from File

The validate_dataframe_checkpoint function validates a Snowpark DataFrame against a checkpoint schema file or dataframe.

from snowflake.snowpark import DataFrame as SnowparkDataFrame
from snowflake.snowpark_checkpoints.job_context import SnowparkJobContext
from snowflake.snowpark_checkpoints.utils.constant import (
    CheckpointMode,
)
from snowflake.snowpark_checkpoints.spark_migration import SamplingStrategy
from typing import Any, Optional

# Signature of the function
def validate_dataframe_checkpoint(
    df: SnowparkDataFrame,
    checkpoint_name: str,
    job_context: Optional[SnowparkJobContext] = None,
    mode: Optional[CheckpointMode] = CheckpointMode.SCHEMA,
    custom_checks: Optional[dict[Any, Any]] = None,
    skip_checks: Optional[dict[Any, Any]] = None,
    sample_frac: Optional[float] = 1.0,
    sample_number: Optional[int] = None,
    sampling_strategy: Optional[SamplingStrategy] = SamplingStrategy.RANDOM_SAMPLE,
    output_path: Optional[str] = None,
):
...

• df: Snowpark dataframe to validate.
• checkpoint_name: Name of the checkpoint schema file or dataframe.
• job_context: Snowpark job context.
• mode: Checkpoint mode (schema or data).
• custom_checks: Custom checks to perform.
• skip_checks: Checks to skip.
• sample_frac: Fraction of the dataframe to sample.
• sample_number: Number of rows to sample.
• sampling_strategy: Sampling strategy to use.
• output_path: Output path for the checkpoint report.

Usage Example

from snowflake.snowpark import Session
from snowflake.snowpark_checkpoints.utils.constant import (
    CheckpointMode,
)
from snowflake.snowpark_checkpoints.checkpoint import validate_dataframe_checkpoint
from snowflake.snowpark_checkpoints.spark_migration import SamplingStrategy
from snowflake.snowpark_checkpoints.job_context import SnowparkJobContext
from pyspark.sql import SparkSession

session = Session.builder.getOrCreate()
job_context = SnowparkJobContext(
    session, SparkSession.builder.getOrCreate(), "job_context", True
)
df = session.read.format("csv").load("data.csv")

validate_dataframe_checkpoint(
    df,
    "schema_checkpoint",
    job_context=job_context,
    mode=CheckpointMode.SCHEMA,
    sample_frac=0.1,
    sampling_strategy=SamplingStrategy.RANDOM_SAMPLE
)

Check with Spark Decorator

The check_with_spark decorator converts any Snowpark dataframe arguments to a function, samples them, and converts them to PySpark dataframe. It then executes a provided Spark function and compares the outputs between the two implementations.

from snowflake.snowpark_checkpoints.job_context import SnowparkJobContext
from snowflake.snowpark_checkpoints.spark_migration import SamplingStrategy
from typing import Callable, Optional, TypeVar

fn = TypeVar("F", bound=Callable)

# Signature of the decorator
def check_with_spark(
    job_context: Optional[SnowparkJobContext],
    spark_function: fn,
    checkpoint_name: str,
    sample_number: Optional[int] = 100,
    sampling_strategy: Optional[SamplingStrategy] = SamplingStrategy.RANDOM_SAMPLE,
    output_path: Optional[str] = None,
) -> Callable[[fn], fn]:
    ...

• job_context: Snowpark job context.
• spark_function: PySpark function to execute.
• checkpoint_name: Name of the check.
• sample_number: Number of rows to sample.
• sampling_strategy: Sampling strategy to use.
• output_path: Output path for the checkpoint report.

Usage Example

from snowflake.snowpark import Session
from snowflake.snowpark import DataFrame as SnowparkDataFrame
from snowflake.snowpark_checkpoints.spark_migration import check_with_spark
from snowflake.snowpark_checkpoints.job_context import SnowparkJobContext
from pyspark.sql import DataFrame as SparkDataFrame, SparkSession

session = Session.builder.getOrCreate()
job_context = SnowparkJobContext(
    session, SparkSession.builder.getOrCreate(), "job_context", True
)

def my_spark_scalar_fn(df: SparkDataFrame):
    return df.count()

@check_with_spark(
    job_context=job_context,
    spark_function=my_spark_scalar_fn,
    checkpoint_name="count_checkpoint",
)
def my_snowpark_scalar_fn(df: SnowparkDataFrame):
    return df.count()

df = job_context.snowpark_session.create_dataframe(
    [[1, 2], [3, 4]], schema=["a", "b"]
)
count = my_snowpark_scalar_fn(df)

Pandera Snowpark Decorators

The decorators @check_input_schema and @check_output_schema allow for sampled schema validation of Snowpark dataframes in the input arguments or in the return value.

from snowflake.snowpark_checkpoints.spark_migration import SamplingStrategy
from snowflake.snowpark_checkpoints.job_context import SnowparkJobContext
from pandera import DataFrameSchema
from typing import Optional

# Signature of the decorator
def check_input_schema(
    pandera_schema: DataFrameSchema,
    checkpoint_name: str,
    sample_frac: Optional[float] = 1.0,
    sample_number: Optional[int] = None,
    sampling_strategy: Optional[SamplingStrategy] = SamplingStrategy.RANDOM_SAMPLE,
    job_context: Optional[SnowparkJobContext] = None,
    output_path: Optional[str] = None,
):
    ...

# Signature of the decorator
def check_output_schema(
    pandera_schema: DataFrameSchema,
    checkpoint_name: str,
    sample_frac: Optional[float] = 1.0,
    sample_number: Optional[int] = None,
    sampling_strategy: Optional[SamplingStrategy] = SamplingStrategy.RANDOM_SAMPLE,
    job_context: Optional[SnowparkJobContext] = None,
    output_path: Optional[str] = None,
):
    ...

• pandera_schema: Pandera schema to validate.
• checkpoint_name: Name of the checkpoint schema file or DataFrame.
• sample_frac: Fraction of the DataFrame to sample.
• sample_number: Number of rows to sample.
• sampling_strategy: Sampling strategy to use.
• job_context: Snowpark job context.
• output_path: Output path for the checkpoint report.

Usage Example

Check Input Schema Example

from pandas import DataFrame as PandasDataFrame
from pandera import DataFrameSchema, Column, Check
from snowflake.snowpark import Session
from snowflake.snowpark import DataFrame as SnowparkDataFrame
from snowflake.snowpark_checkpoints.checkpoint import check_input_schema
from numpy import int8

df = PandasDataFrame(
    {
        "COLUMN1": [1, 4, 0, 10, 9],
        "COLUMN2": [-1.3, -1.4, -2.9, -10.1, -20.4],
    }
)

in_schema = DataFrameSchema(
    {
        "COLUMN1": Column(int8, Check(lambda x: 0 <= x <= 10, element_wise=True)),
        "COLUMN2": Column(float, Check(lambda x: x < -1.2, element_wise=True)),
    }
)

@check_input_schema(in_schema, "input_schema_checkpoint")
def preprocessor(dataframe: SnowparkDataFrame):
    dataframe = dataframe.withColumn(
        "COLUMN3", dataframe["COLUMN1"] + dataframe["COLUMN2"]
    )
    return dataframe

session = Session.builder.getOrCreate()
sp_dataframe = session.create_dataframe(df)

preprocessed_dataframe = preprocessor(sp_dataframe)

Check Input Schema Example

from pandas import DataFrame as PandasDataFrame
from pandera import DataFrameSchema, Column, Check
from snowflake.snowpark import Session
from snowflake.snowpark import DataFrame as SnowparkDataFrame
from snowflake.snowpark_checkpoints.checkpoint import check_output_schema
from numpy import int8

df = PandasDataFrame(
    {
        "COLUMN1": [1, 4, 0, 10, 9],
        "COLUMN2": [-1.3, -1.4, -2.9, -10.1, -20.4],
    }
)

out_schema = DataFrameSchema(
    {
        "COLUMN1": Column(int8, Check.between(0, 10, include_max=True, include_min=True)),
        "COLUMN2": Column(float, Check.less_than_or_equal_to(-1.2)),
        "COLUMN3": Column(float, Check.less_than(10)),
    }
)

@check_output_schema(out_schema, "output_schema_checkpoint")
def preprocessor(dataframe: SnowparkDataFrame):
    return dataframe.with_column(
        "COLUMN3", dataframe["COLUMN1"] + dataframe["COLUMN2"]
    )

session = Session.builder.getOrCreate()
sp_dataframe = session.create_dataframe(df)

preprocessed_dataframe = preprocessor(sp_dataframe)

Skip validation

The method xvalidate_dataframe_checkpoint can be used to avoid the validation of the checkpoint defined. The result of the checkpoint will be SKIP and a message will be logged in the terminal. The method contains the same signature of validate_dataframe_checkpoint.

Usage Example

from snowflake.snowpark import Session
from snowflake.snowpark_checkpoints.utils.constant import (
    CheckpointMode,
)
from snowflake.snowpark_checkpoints.checkpoint import validate_dataframe_checkpoint
from snowflake.snowpark_checkpoints.spark_migration import SamplingStrategy
from snowflake.snowpark_checkpoints.job_context import SnowparkJobContext
from pyspark.sql import SparkSession

session = Session.builder.getOrCreate()
job_context = SnowparkJobContext(
    session, SparkSession.builder.getOrCreate(), "job_context", True
)
df = session.read.format("csv").load("data.csv")

xvalidate_dataframe_checkpoint(
    df,
    "schema_checkpoint",
    job_context=job_context,
    mode=CheckpointMode.SCHEMA,
    sample_frac=0.1,
    sampling_strategy=SamplingStrategy.RANDOM_SAMPLE
)

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