fix-convergence.py

"""Helper script to fix some Heat convergence issues.

Up until queens, Heat had a few bugs which could result in unresolved
references to resources that are not present in the database. That ends up
making some operations using resources stuck IN_PROGRESS.

This script fixed a few of those issues, removing the dead references.

USE AT YOUR OWN RISK. Please make a backup of your database before using it.
It's also encouraged to stop any Heat engines to prevent bad interaction.
"""
import argparse
import json

import pymysql

def main(do_commit):
    def commit():
        if do_commit:
            connection.commit()
    connection = pymysql.connect(user="root", database="heat")
    try:
        with connection.cursor() as cursor:
            cursor.execute(
                "select resource.id from resource "
                "left join resource as reqres on "
                "resource.replaced_by = reqres.id where reqres.id is null "
                "and resource.replaced_by is not null")
            update = "update resource set replaced_by = null where id = %s"
            for (resource,) in cursor.fetchall():
                print("Fixed replaced_by for %s" % resource)
                cursor.execute(update, (resource,))
            commit()

        with connection.cursor() as cursor:
            cursor.execute(
                "select resource.id from resource "
                "left join resource as reqres on "
                "resource.replaces = reqres.id where reqres.id is null "
                "and resource.replaces is not null")
            update = "update resource set replaces = null where id = %s"
            for (resource,) in cursor.fetchall():
                print("Fixed replaces for %s" % resource)
                cursor.execute(update, (resource,))
            commit()

        with connection.cursor() as cursor:
            query = ("select resource.id, resource.requires from "
                    "resource left join resource as reqres on "
                     "json_extract(resource.requires, '$[%s]') = reqres.id "
                     "where reqres.id is NULL and "
                     "json_extract(resource.requires, '$[%s]') is not null")
            for i in range(10):
                cursor.execute(query, (i, i))
                update = "update resource set requires = %s where id = %s"
                for (resource, requires) in cursor.fetchall():
                    print("Fixed requires for %s" % resource)
                    requires = json.loads(requires)
                    del requires[i]
                    cursor.execute(update, (json.dumps(requires), resource))
            commit()

        with connection.cursor() as cursor:
            query = ("select resource.id, resource.needed_by from "
                    "resource left join resource as reqres on "
                     "json_extract(resource.needed_by, '$[%s]') = reqres.id "
                     "where reqres.id is NULL and "
                     "json_extract(resource.needed_by, '$[%s]') is not null")
            for i in range(10):
                cursor.execute(query, (i, i))
                update = "update resource set needed_by = %s where id = %s"
                for (resource, needed_by) in cursor.fetchall():
                    print("Fixed needed_by for %s" % resource)
                    needed_by = json.loads(needed_by)
                    del needed_by[i]
                    cursor.execute(update, (json.dumps(needed_by), resource))
            commit()

    finally:
        connection.close()

if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="Fix Heat convergence issues.")
    parser.add_argument("--commit", action="store_true",
                        help="If set, will commit fixes")
    args = parser.parse_args()
    main(args.commit)