Using Liquibase MongoDB Pro with Amazon DocumentDB

You can use Liquibase Pro with Amazon DocumentDB, which is a NoSQL database that offers partial MongoDB compatibility. You can use most of the same drivers, application code, and tools in Amazon DocumentDB as you do in MongoDB. There are some functional differences between MongoDB and Amazon DocumentDB, but you can configure your Liquibase project to work with DocumentDB with only a few tweaks.

Amazon DocumentDB emulates the MongoDB API while running over Amazon Aurora on the back-end. Your Amazon DocumentDB database contains one or more clusters containing your database instance. Clusters are deployed within an Amazon Virtual Private Cloud (Amazon VPC) environment.

You need a valid Liquibase Pro license key to use Liquibase with Amazon DocumentDB through the MongoDB Pro Extension. If you want to use Liquibase Pro with MongoDB instead of Amazon DocumentDB, see Using Liquibase MongoDB Pro with MongoDB Community and Enterprise Server.

Verified database versions

Amazon DocumentDB versions do not correspond directly to MongoDB versions. Liquibase has been tested on the following Amazon DocumentDB version:

• 4.0

For more information on Liquibase Pro and MongoDB version requirements, see Verified database versions.

Prerequisites

1. Download and Install Liquibase on your machine.
2. Ensure Java is installed: Liquibase requires Java to run. If you used the Liquibase Installer, Java is included automatically. Otherwise, you must install Java manually.
3. If you use Liquibase Pro, or a Liquibase Pro extension, confirm that you have a valid license key. For more information, see How to Apply Your Liquibase Pro License Key

Download the extension

Download the latest version of the Liquibase MongoDB Pro Extension here.

Install drivers

CLI users

Pro extension users do not need to install drivers as long as you have placed the liquibase-commercial-mongodb-<version>. jar file in the $LIQUIBASE_HOME/lib directory.

Tip: $LIQUIBASE_HOME is an environment variable that points to the location of the directory where Liquibase is installed on your machine. You can set environment variables using your operating system's shell. The location of $LIQUIBASE_HOME will depend on where Liquibase was installed on your machine.

To use Liquibase Pro and Amazon DocumentDB (with MongoDB compatibility), you should not specify a driver in the liquibase.properties file so that Liquibase recognizes the correct one.

Maven users

Include the liquibase-commercial-mongodb-<version>. jar file as a dependency in your pom.xml file. Using this information, Maven automatically downloads any required JAR files from Maven Central when you build your project.

<dependency>
    <groupId>org.liquibase.ext</groupId>
    <artifactId>liquibase-commercial-mongodb</artifactId>
    <version>1.5.0</version>
</dependency>

Implement Amazon DocumentDB

1. Ensure that your desired Role Based Access Controls (RBAC) are established before continuing.
2. Download and Install mongosh if it is not already installed on your machine.

Note: mongosh is mandatory to use MongoDB with Liquibase Pro and it must be accessible to Liquibase. We recommend that mongosh is in the system PATH environment variable. If it is not, that location of mongosh must be manually specified in the liquibase.mongosh.conf file.

3. Download Java 11. The MongoDB Pro Extension requires it.

Tip: Java 11 may already be present on your machine if you used the installer to install Liquibase. We recommend installing Liquibase with Java 11 with the installer asset available on GitHub.

4. Set the supportsValidator argument to false in one of the following ways:
   • Command line: --supports-validator=false
   • liquibase.properties file: liquibase.mongodb.supportsValidator: false
   • Environment variable: LIQUIBASE_MONGODB_SUPPORTS_VALIDATOR=false
5. Set the retryWrites argument to false in one of the following ways:
   • Command line: --retry-writes=false
   • liquibase.properties file: liquibase.mongodb.retryWrites: false
   • Environment variable: LIQUIBASE_MONGODB_RETRY_WRITES=false
   • JDBC URL: &retryWrites=false. See the following section for examples of full URLs.
6. (Optional) If you are using TLS/SSL, configure the TLS/SSL encrypted connection for Amazon DocumentDB. For a step-by-step guide, see the below drop down guide

Configure connection

1. Ensure your Amazon DocumentDB database is configured. For more information, see AWS Documentation: Get Started with Amazon DocumentDB.

2. Ensure your Liquibase Pro license key is specified. For example, in a liquibase.properties file (defaults file):

   licenseKey: zQl8kNZjZgSp9LvqWQFAtGwiHrpg97UyAfQrNSiJQBCDH8FQPdDzANUpIe4Bj3CZA2IXgDBaoYZFvMw0E/s4JcECB3/A6jO+...

3. Specify the database URL in the liquibase.properties file (defaults file), along with other properties you want to set a default value for. Liquibase does not parse the URL. You can either specify the full database connection string or specify the URL using your database's standard connection format:

TLS on:

url: mongodb://localhost:27070/lbcat?tls=true&tlsAllowInvalidHostnames=true&retryWrites=false&tlsCAFile=rds-combined-ca-bundle.pem

TLS off:

url: mongodb://localhost:27069/lbcat?tls=false&retryWrites=false

Note: If you set retryWrites to false anywhere in your Liquibase project and to true elsewhere in your project—in the CLI, in your liquibase.properties file, as an environment variable, in the url argument, and so on—the value of false will always take priority, regardless of where you set it.

Tip: To apply a Liquibase Pro key to your project, add the following property to the Liquibase properties file: licenseKey: <paste code here>

Test connection

1. Create a text file called changelog (.js, .yaml, .json, or .xml) in your project directory and add a changeset.

You can write Liquibase changelogs in the MongoDB Pro extension in these ways:

• Native MongoDB Shell (mongosh) scripts in MongoDB Query Language (MQL): let developers use Liquibase without modifying existing MQL scripts, which may be JavaScript (.js) files.
• Formatted Mongo changelogs (MongoDB Pro 1.3.0+): add Liquibase changeset metadata to your MQL scripts to use features like rollback, contexts, labels, and the include and includeAll tags. These must be saved as .js files.
• YAML, JSON, and XML modeled changelogs: specify changes for Liquibase to deploy without the need for MQL scripts. However, you can still deploy MQL scripts in YAML, JSON, and XML changelogs by using the mongo and mongoFile Change Types. Using these Change Types requires you to specify mongosh as the value of the runWith attribute for all mongo and mongoFile changesets.
• Raw mongosh example
• Formatted mongosh example
• YAML example
• JSON example
• XML example

The MongoDB Pro extension lets you use MongoDB's native language of MongoDB Query Language (MQL), which you may be storing in JavaScript files, in Liquibase changesets and Change Types. This is possible because MongoDB Shell (mongosh) is compatible with Liquibase Pro. For more information, see MongoDB: Write Scripts. Example syntax:

db.createCollection('customers');

With the Liquibase MongoDB Pro extension 1.3.0+, you can use a formatted Mongo changelog for MongoDB Pro, similar to a formatted SQL changelog. This lets you use mongosh scripts written in MongoDB Query Language (MQL) directly in Liquibase while also having access to all Liquibase features.

All Liquibase formatted Mongo changelogs must use the file extension .JS or .js (JavaScript). They must also begin with a changelog header: // liquibase formatted mongodb. Your changesets must each specify runWith:mongosh. For example:

// liquibase formatted mongodb

// changeset your.name:1 labels:example-label context:example-context runWith:mongosh
// comment: example comment

db.createCollection('customers');

// rollback db = db.customers.drop()

databaseChangeLog:
  - changeSet:
      id: 1
      author: your.name
      runWith: mongosh
      changes:
        - mongo:
            mongo: "db.createCollection('person')"
            dbms: mongodb
        - rollback:
            mongo:
              mongo: "db.person.drop()"

  - changeSet:
      id: 2
      author: your.name
      runWith: mongosh
      changes:
        - mongoFile:
            path: "scriptFile.txt"
            dbms: mongodb
            relativeToChangelogFile: "true"
        - rollback:
            mongo:
              mongo: "db.company.drop()"

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "1",
        "author": "your.name",
        "runWith": "mongosh",
        "changes": [
          {
            "mongo": {
              "dbms": "mongodb",
              "mongo": "db.createCollection('person')"
            }
          }
        ],
        "rollback": [
          {
            "mongo": {
              "mongo": "db.person.drop()"
            }
          }
        ]
      }
    },
    {
      "changeSet": {
        "id": "2",
        "author": "your.name",
        "runWith": "mongosh",
        "changes": [
          {
            "mongoFile": {
              "dbms": "mongodb",
              "path": "scriptFile.txt",
              "relativeToChangelogFile": true
            }
          }
        ],
        "rollback": [
          {
            "mongo": {
              "mongo": "db.company.drop()"
            }
          }
        ]
      }
    }
  ]
}

The Liquibase MongoDB Pro extension uses a unique mongodb-pro XML namespace and XSD files in the changelog header. However, the ext prefix used with other extensions is backwards-compatible:

<databaseChangeLog
    xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:mongodb-pro="http://www.liquibase.org/xml/ns/pro-mongodb"
    xmlns:mongodb="http://www.liquibase.org/xml/ns/mongodb"
    xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
    http://www.liquibase.org/xml/ns/pro-mongodb http://www.liquibase.org/xml/ns/pro-mongodb/liquibase-pro-mongodb-latest.xsd
    http://www.liquibase.org/xml/ns/mongodb http://www.liquibase.org/xml/ns/mongodb/liquibase-mongodb-latest.xsd">

    <changeSet id="1" author="your.name" runWith="mongosh">
        <mongodb-pro:mongo dbms="mongodb">
            db.createCollection('person')
        </mongodb-pro:mongo>

        <rollback>
            <mongodb-pro:mongo>
                db.person.drop()
            </mongodb-pro:mongo>
        </rollback>
    </changeSet>

    <changeSet id="2" author="your.name" runWith="mongosh">
        <mongodb-pro:mongoFile dbms="mongodb" path="scriptFile.txt" relativeToChangelogFile="true"/>

        <rollback>
            <mongodb-pro:mongo>
                db.company.drop()
            </mongodb-pro:mongo>
        </rollback>
    </changeSet>

</databaseChangeLog>

Tip: The preceding examples show only the mongo and mongoFile Change Types for Liquibase Pro. For a list of all Liquibase Pro and Liquibase Open Source Change Types for MongoDB, including Change Types that you can without the mongosh native executor, see Liquibase Change Types for MongoDB.

2. Navigate to your project folder in the CLI and run the Liquibase status command to see whether the connection is successful:

Note: You can specify arguments in the CLI or keep them in the Liquibase properties file.

If your connection is successful, you'll see a message like this:

4 changesets have not been applied to <your_connection_url>
Liquibase command 'status' was executed successfully. 

3. Then execute these changes to your database with the update command:

liquibase update --changelog-file=<changelog.xml>

If your update is successful, Liquibase runs each changeset and displays a summary message ending with:

Liquibase: Update has been successful.
Liquibase command 'update' was executed successfully.

4. From a database UI tool, ensure that your database contains the myCollection object you added along with the DATABASECHANGELOG collection and DATABASECHANGELOGLOCK collection.

Tip: You can use MongoDB Compass to easily view collections in your database. For example, run the commands use myDatabase and db.myCollection.find().

Now you're ready to start deploying database changes with Liquibase!

Related links

• Using Liquibase MongoDB Pro with MongoDB Community and Enterprise Server
• AWS DocumentDB: MongoDB Compatibility
• MongoDB: Comparing Amazon DocumentDB and MongoDB