MongoDB Tips

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add user

using python

client.admin.add_user('zhangtemplar', 'tomato7G2262', roles=[ { 'role': "userAdminAnyDatabase", 'db': "admin" } ])

or using mongo shell

db.createUser({user: 'zhangtemplar', pwd: 'tomato7G2262', roles: ['root']})

copy database

client2.admin.command('copydb', fromdb='test', todb='test', fromhost='url:port')

Or you can use mongodump and mongorestore as described below.

merge collection/database

There is not command letting your merge collection or database, thus you need to iteration all the collections and all their documents to merge:

src = client['test']
dst = client['test2']
for name in src.collection_names():
    for doc in src[name].find():
        result = dst[name].replace_one({'_id' : doc['_id']}, doc, upsert=True)
        if result.modified_count > 0:
            print 'updated', doc['_id']
        else:
            print 'inserted', doc['_id']
    print 'finish', name

Authentication

In python with pymongo:

MongoClient('mongodb://user:' + password + '@127.0.0.1')

Search with regular expression

In python with pymongo:

import re
regx = re.compile("^foo", re.IGNORECASE)
db.users.find_one({"files": regx})

Start a mongodb in docker

docker run -p 27017:27017 --name mongo -v /home/ubuntu/mongo/data/db/:/data/db -d mongo:latest --auth

More specially it map ports 27017 to 27017, name the container as mongo, map the local volume /home/ubuntu/mongo/data/db/ to /data/db and enable authorization.

Restore

mongorestore -u $username -p $password --authenticationDatabase=admin --gzip --archive=$backup

It will restore the database from a gzip archive called $backup. If you don’t have authentication, you can skip -u $username -p $password --authenticationDatabase=admin. It will restore all the database but will not overwrite any existing documents. To replace the whole database, please add argument -d. To restore a specific database, please use -database $database.

Backup

To back up all the database:

mongodump --gzip --archive=mongodb_08012017192000.gz

Use Python Eve to Provide Rest Interface for MongoDB

call the api as:

curl -i -g http://url:port/user?where={"id":"some-id"}

Note url and port are for eve.

start python-eve

docker run --detach --volume /home/ubuntu/eve/src:/src --name python-eve -p 5000:5000 zhangtemplar/docker-python-eve:3.5

pymongo join

pipeline = [{"$lookup": {"from":"user_keyword", "localField":"id","foreignField":"userId","as":"keyword" }}, {'$match': {'id' : 'https://angel.co/paul-judge-1'}}]
result = client['angellist']['user'].aggregate(pipeline)

Written on August 13, 2017