MongoDB

Tutorials

Name	Description
Guru99 MongoDB Tutorial	MongoDB Tutorial
Tutorialspoint Tutorial	MongoDB Tutorial

Authentication and Authorization

Name	Description
Tutorial User Administration Without You Integrating LDAP with MongoDB	Full explanation on Mongo and LDAP integration

Cheat Sheet

Mongo Shell

General

• DB stats: db.stats()
• Switch to a DB: use DB_NAME
• Show collections: show collections
• Show all the document in a collection: db.COLLECTION_NAME.find({})
• Count the number of documents in a collection: db.COLLECTION_NAME.count()
• Remove all the documents from a collection: db.COLLECTION_NAME.remove({})
• Remove field from all documents: db.COLLECTION_NAME.update({}, {$unset: { FIELD_NAME: ""}}, {multi:true})
• Rename field: db.hosts.updateMany( {}, { $rename: { "CURRENT_FIELD_NAME": "NEW_FIELD_NAME" } } )

Mongoexport

• Export Mongo DB collection to a JSON file: mongoexport --db=DB_NAME --collection=COLLECTION_NAME --out=data.json
• Export specific fields from a Mongo DB collection to a JSON file: mongoexport --db=DB_NAME --fields=FIELD_NAME,FIELD_NAME2 --collection=COLLECTION_NAME --out=data.json

Aggregations

• Count the number of documents: db.accounts.aggregate([ { "$count": "number of documents" }])
• Show only the sub element 'attachment_uuids': db.accounts.aggregate( [ {$project: {"hosts.attachment_uuids": 1, _id:0}} ] )

Users

• Display users:

use admin
db.getUsers()

• Create administrative user

use admin
db.createUser({user: "admin", pwd: "some_password", roles: ["root"]})

• Authentice: db.auth(USERNAME, PASSWORD)

Roles

• Display roles

use admin
db.getRoles()

• Drop/Remove role: db.dropRole("NAME_OF_THE_ROLE")

LDAP

• Mongo Conf LDAP configuration

security:
  # authorization: "enabled"
  ldap:
    servers: 'some.ldap.server.com'
    userToDNMapping:
         '[
            {
               match: "(.+)",
               ldapQuery: "DC=X,DC=com??sub?(uid={0})"
            }
         ]'
    authz:
         queryTemplate: "{USER}?memberOf?base"
setParameter:
  authenticationMechanisms: 'PLAIN,SCRAM-SHA-1'

• Create role where the LDAP group "unicorns" has permissions to only run 'find' on "hosts" collection in 'test' db:

db.createRole({role:"cn=unicorns,ou=groups,dc=X,dc=com", privileges: [{ resource: {db: "", collection: "hosts"}, actions: ["find"]}], roles: [{ role: "read", db: "test"}]})

• Drop/Remove role from the previous example: db.dropRole("cn=unicorns,ou=groups,dc=X,dc=com")

Mongo Python

• Add new element to an arrray only if it doesn't exists already

mongo_client.update(
       { "account_number": account_num },
       { "$addToSet": { "hosts": {'hostname': hostname} } }
    )

• Add a new element to an array in sub-document (if it doesn't exists already):

mongo_client.update_one(
       { "account_number": account_num, "hosts.hostname": hostname },
       { "$addToSet": { "hosts.$.attachment_uuids": attachment_uuid } }
    )

• Add all the elements in an array to an array in document (This is not about adding the array as it is but adding the elements of it):

mongo_client.update_one(
    {'_id': 1},
    {'$addToSet': {'some_list': { '$each': [1, 2, 3]} }}, upsert=True)