Python script to convert mysqldump output to JSON file

README.md

mysqldump to JSON

Python script to convert mysqldump output to JSON file. Most of the code was borrowed from github.com/jamesmishra/mysqldump-to-csv

You'll want to update the 'parse_row' function to map each item in a row to a dictionary.

Running the script

cat MySQLdump20151012.sql | python mysqldump2json.py > dump.json

mysqldump2json.py

#!/usr/bin/env python
import fileinput
import csv
import json
import sys

# This prevents prematurely closed pipes from raising
# an exception in Python
from signal import signal, SIGPIPE, SIG_DFL

signal(SIGPIPE, SIG_DFL)

# The csv file might contain very huge fields,
# therefore increase the field_size_limit
csv.field_size_limit(sys.maxsize)


def is_insert(line):
    """
    Returns true if the line begins a SQL insert statement.
    """
    return line.startswith('INSERT INTO') or False


def get_values(line):
    """
    Returns the portion of an INSERT statement containing values
    """
    return line.partition('` VALUES ')[2]


def values_sanity_check(values):
    """
    Ensures that values from the INSERT statement meet basic checks.
    """
    assert values
    assert values[0] == '('
    # Assertions have not been raised
    return True


def parse_row(row):
    return {
        'id': row[2],
        'created': row[5],
        'text': row[8]
    }


def parse_values(values, outfile):
    """
    Given a file handle and the raw values from a MySQL INSERT
    statement, write the equivalent CSV to the file
    """
    latest_row = []

    reader = csv.reader([values], delimiter=',',
                        doublequote=False,
                        escapechar='\\',
                        quotechar="'",
                        strict=True
                        )

    transactions = []
    for reader_row in reader:
        for column in reader_row:
            # If our current string is empty...
            if len(column) == 0:
                latest_row.append('""')
                continue
            # If our string starts with an open paren
            if column[0] == "(":
                # Assume that this column does not begin
                # a new row.
                new_row = False
                # If we've been filling out a row
                if len(latest_row) > 0:
                    # Check if the previous entry ended in
                    # a close paren. If so, the row we've
                    # been filling out has been COMPLETED
                    # as:
                    #    1) the previous entry ended in a )
                    #    2) the current entry starts with a (
                    if latest_row[-1][-1] == ")":
                        # Remove the close paren.
                        latest_row[-1] = latest_row[-1][:-1]
                        new_row = True
                # If we've found a new row, write it out
                # and begin our new one
                if new_row:
                    json_row = parse_row(latest_row)
                    if json_row.get('text', '') != '':
                        transactions.append(json_row)
                    latest_row = []
                # If we're beginning a new row, eliminate the
                # opening parentheses.
                if len(latest_row) == 0:
                    column = column[1:]
            # Add our column to the row we're working on.
            latest_row.append(column)
        # At the end of an INSERT statement, we'll
        # have the semicolon.
        # Make sure to remove the semicolon and
        # the close paren.
        if latest_row[-1][-2:] == ");":
            latest_row[-1] = latest_row[-1][:-2]
            json_row = parse_row(latest_row)
            if json_row.get('text', '') != '':
                transactions.append(json_row)

    outfile.write(json.dumps(transactions))


def main():
    """
    Parse arguments and start the program
    """
    # Iterate over all lines in all files
    # listed in sys.argv[1:]
    # or stdin if no args given.
    try:
        for line in fileinput.input():
            # Look for an INSERT statement and parse it.
            if is_insert(line):
                values = get_values(line)
                if values_sanity_check(values):
                    parse_values(values, sys.stdout)
    except KeyboardInterrupt:
        sys.exit(0)


if __name__ == "__main__":
    main()

Traceback (most recent call last):
  File "mysqldump2json.py", line 133, in <module>
    main()
  File "mysqldump2json.py", line 126, in main
    if values_sanity_check(values):
  File "mysqldump2json.py", line 36, in values_sanity_check
    assert values
AssertionError

It doesn't work. The node version doesn't work because the database is too big.