mongodb去重

{unique : true, dropDups : true}   # 无法使用了

from pymongo import DeleteOne
from threading import Thread
from apscheduler.schedulers.blocking import BlockingScheduler
from Application.Utils.Log import Log


class DupKeywordRemove:
    def __init__(self):
        models = [monde1, monde2, monde2,
                  monde3, monde4, monde4]  # mongoengine的modle
        self.pipeline = [
            # 根据几个字段去判断键值对的唯一性，这里特别写明了{"$exists": True}，必须保证需要判断的字段完成，否则会影响到后面的group
            {"$match": {
                "keyword": {"$exists": True},
                "country_id": {"$exists": True},
            }},
            # 将重复的键值对group起来，并用count计数
            {"$group": {
                "_id": {
                    "keyword": "$keyword",
                    "country_id": "$country_id",
                },
                "count": {"$sum": 1}
            }},
            # 匹配count大于2的键值对，他们就是重复的
            {"$match": {
                "count": {"$gt": 1}
            }}
        ]
        self.main(models)

    def find_dup_id(self, model):
        try:
            _collection = model._get_collection()
            # 配置allowDiskUse=True应对mongodb的16M limit
            all_dup_key = list(_collection.aggregate(self.pipeline, allowDiskUse=True))
            delete_list = []
            # 重复的doc作为list返回，每一组键值对作为find条件去数据库里查询
            for dup_event in all_dup_key:
                match_pipe = dup_event[‘_id‘]
                remove_id_list = []
                dups = list(_collection.find(match_pipe))
                if len(dups) >= 2:
                    for key in dups:
                        remove_id_list.append(key[‘_id‘])
                    needToSave = remove_id_list.pop()  # pop一个出去，作为保留的doc
                    for to_del in remove_id_list:
                        delete_list.append(
                            DeleteOne({
                                ‘_id‘: to_del
                            })
                        )
            print(_collection, len(delete_list))
            if delete_list:
                print(‘删除重复数据‘)
                _collection.bulk_write(delete_list)
            else:
                print(‘无重复数据‘)
                pass
        except Exception as e:
            Log(‘keyword_dup_remove‘).info(e)

    def main(self, models):
        t_li = []
        for _model in models:
            t_li.append(
                Thread(
                    target=self.find_dup_id,
                    kwargs={
                        ‘model‘: _model,
                    }
                )
            )
        for t in t_li:
            t.start()
        for t in t_li:
            t.join()


if __name__ == ‘__main__‘:
    DupKeywordRemove()