spark-instrumented-optimizer/python/pyspark/sql/utils.py

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# Licensed to the Apache Software Foundation (ASF) under one or more
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# The ASF licenses this file to You under the Apache License, Version 2.0
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#    http://www.apache.org/licenses/LICENSE-2.0
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import py4j


class AnalysisException(Exception):
    """
    Failed to analyze a SQL query plan.
    """


def capture_sql_exception(f):
    def deco(*a, **kw):
        try:
            return f(*a, **kw)
        except py4j.protocol.Py4JJavaError as e:
            s = e.java_exception.toString()
            if s.startswith('org.apache.spark.sql.AnalysisException: '):
                raise AnalysisException(s.split(': ', 1)[1])
            raise
    return deco


def install_exception_handler():
    """
    Hook an exception handler into Py4j, which could capture some SQL exceptions in Java.

    When calling Java API, it will call `get_return_value` to parse the returned object.
    If any exception happened in JVM, the result will be Java exception object, it raise
    py4j.protocol.Py4JJavaError. We replace the original `get_return_value` with one that
    could capture the Java exception and throw a Python one (with the same error message).

    It's idempotent, could be called multiple times.
    """
    original = py4j.protocol.get_return_value
    # The original `get_return_value` is not patched, it's idempotent.
    patched = capture_sql_exception(original)
    # only patch the one used in in py4j.java_gateway (call Java API)
    py4j.java_gateway.get_return_value = patched