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This repository contains the guide documentation source. To view the guide in published form, view it on the Open Liberty website. |
Learn how to persist data in your microservices to MongoDB, a document-oriented NoSQL database.
You will learn how to use MongoDB to build and test a simple microservice that manages the members of a crew. The microservice will respond to POST, GET, PUT, and DELETE requests that manipulate the database.
The crew members will be stored in MongoDB as documents in the following JSON format:
{
"_id": {
"$oid": "5dee6b079503234323db2ebc"
},
"Name": "Member1",
"Rank": "Captain",
"CrewID": "000001"
}This microservice connects to MongoDB by using Transport Layer Security (TLS) and injects a MongoDatabase instance into the service with a Contexts and Dependency Injection (CDI) producer. Additionally, MicroProfile Config is used to easily configure the MongoDB driver.
For more information about CDI and MicroProfile Config, see the guides on Injecting dependencies into microservices and Separating configuration from code in microservices.
You will use Docker to run an instance of MongoDB for a fast installation and setup. Install Docker by following the instructions in the official Docker documentation, and start your Docker environment.
This guide uses Docker to run an instance of MongoDB. A multi-stage Dockerfile is provided for you. This Dockerfile uses the mongo image as the base image of the final stage and gathers the required configuration files. The resulting mongo image runs in a Docker container, and you must set up a new database for the microservice. Lastly, the truststore that’s generated in the Docker image is copied from the container and placed into the Open Liberty configuration.
You can find more details and configuration options on the MongoDB website. For more information about the mongo image, see mongo in Docker Hub.
Running MongoDB in a Docker container
Run the following commands to use the Dockerfile to build the image, run the image in a Docker container, and map port 27017 from the container to your host machine:
docker build -t mongo-sample -f assets/Dockerfile .
docker run --name mongo-guide -p 27017:27017 -d mongo-sampleAdding the truststore to the Open Liberty configuration
The truststore that’s created in the container needs to be added to the Open Liberty configuration so that the Liberty can trust the certificate that MongoDB presents when they connect. Run the following command to copy the truststore.p12 file from the container to the start and finish directories:
docker cp ^
mongo-guide:/home/mongodb/certs/truststore.p12 ^
start/src/main/liberty/config/resources/security
docker cp ^
mongo-guide:/home/mongodb/certs/truststore.p12 ^
finish/src/main/liberty/config/resources/securitydocker cp \
mongo-guide:/home/mongodb/certs/truststore.p12 \
start/src/main/liberty/config/resources/security
docker cp \
mongo-guide:/home/mongodb/certs/truststore.p12 \
finish/src/main/liberty/config/resources/securitydocker cp \
mongo-guide:/home/mongodb/certs/truststore.p12 \
start/src/main/liberty/config/resources/security
docker cp \
mongo-guide:/home/mongodb/certs/truststore.p12 \
finish/src/main/liberty/config/resources/securityYou can now check out the service by going to the http://localhost:9080/mongo/ URL.
Navigate to the start directory to begin.
With a CDI producer, you can easily provide a MongoDatabase to your microservice.
Create theMongoProducerclass.src/main/java/io/openliberty/guides/mongo/MongoProducer.java
MongoProducer.java
link:finish/src/main/java/io/openliberty/guides/mongo/MongoProducer.java[role=include]microprofile-config.properties
link:finish/src/main/resources/META-INF/microprofile-config.properties[role=include]pom.xml
link:finish/pom.xml[role=include]server.xml
link:finish/src/main/liberty/config/server.xml[role=include]The values from the microprofile-config.properties file are injected into the MongoProducer class. The MongoProducer class requires the following methods for the MongoClient:
-
The
createMongo()producer method returns an instance ofMongoClient. In this method, the username, database name, and decoded password are passed into theMongoCredential.createCredential()method to get an instance ofMongoCredential. TheJSSEHelpergets theSSLContextfrom theoutboundSSLContextin theserver.xmlconfiguration file. Then, aMongoClientinstance is created. -
The
createDB()producer method returns an instance ofMongoDatabasethat depends on theMongoClient. This method injects theMongoClientin its parameters and passes the database name into theMongoClient.getDatabase()method to get aMongoDatabaseinstance. -
The
close()method is a clean-up function for theMongoClientthat closes the connection to theMongoDatabaseinstance.
You are going to implement the basic create, retrieve, update, and delete (CRUD) operations in the CrewService class. The com.mongodb.client and com.mongodb.client.result packages are used to help implement these operations for the microservice. For more information about these packages, see the com.mongodb.client and com.mongodb.client.result Javadoc. For more information about creating a RESTful service with JAX-RS, JSON-B, and Open Liberty, see the guide on Creating a RESTful web serivce.
Create theCrewServiceclass.src/main/java/io/openliberty/guides/application/CrewService.java
CrewService.java
link:finish/src/main/java/io/openliberty/guides/application/CrewService.java[role=include]CrewMember.java
link:finish/src/main/java/io/openliberty/guides/application/CrewMember.java[role=include]In this class, a Validator is used to validate a CrewMember before the database is updated. The CDI producer is used to inject a MongoDatabase into the CrewService class.
Implementing the Create operation
The add() method handles the implementation of the create operation. An instance of MongoCollection is retrieved with the MongoDatabase.getCollection() method. The Document type parameter specifies that the Document type is used to store data in the MongoCollection. Each crew member is converted into a Document, and the MongoCollection.insertOne() method inserts a new crew member document.
Implementing the Retrieve operation
The retrieve() method handles the implementation of the retrieve operation. The Crew collection is retrieved with the MongoDatabase.getCollection() method. Then, the MongoCollection.find() method retrieves a FindIterable object. This object is iterable for all the crew members documents in the collection, so each crew member document is concatenated into a String array and returned.
Implementing the Update operation
The update() method handles the implementation of the update operation. After the Crew collection is retrieved, a document is created with the specified object id and is used to query the collection. Next, a new crew member Document is created with the updated configuration. The MongoCollection.replaceOne() method is called with the query and new crew member document. This method updates all of the matching queries with the new document. Because the object id is unique in the Crew collection, only one document is updated. The MongoCollection.replaceOne() method also returns an UpdateResult instance, which determines how many documents matched the query. If there are zero matches, then the object id doesn’t exist.
Implementing the Delete operation
The remove() method handles the implementation of the delete operation. After the Crew collection is retrieved, a Document is created with the specified object id and is used to query the collection. Because the object id is unique in the Crew collection, only one document is deleted. After the document is deleted, the MongoCollection.deleteOne() method returns a DeleteResult instance, which determines how many documents were deleted. If zero documents were deleted, then the object id doesn’t exist.
MicroProfile Config makes configuring the MongoDB driver simple because all of the configuration can be set in one place and injected into the CDI producer.
Create the configuration file.
src/main/resources/META-INF/microprofile-config.properties
microprofile-config.properties
link:finish/src/main/resources/META-INF/microprofile-config.properties[role=include]Values such as the hostname, port, and database name for the running MongoDB instance are set in this file. The user’s username and password are also set here. For added security, the password was encoded by using the securityUtility encode command.
To create a CDI producer for MongoDB and connect over TLS, the Open Liberty needs to be correctly configured.
Replace the Libertyserver.xmlconfiguration file.src/main/liberty/config/server.xml
server.xml
link:finish/src/main/liberty/config/server.xml[role=include]The features that are required to create the CDI producer for MongoDB are Contexts and Dependency Injection (cdi-4.0), Secure Socket Layer (ssl-1.0), MicroProfile Config (mpConfig-3.1), and Password Utilities (passwordUtilities-1.1). These features are specified in the featureManager element. The Secure Socket Layer (SSL) context is configured in the server.xml configuration file so that the application can connect to MongoDB with TLS. The keyStore element points to the truststore.p12 keystore file that was created in one of the previous sections. The ssl element specifies the defaultKeyStore as the keystore and outboundTrustStore as the truststore.
After you replace the server.xml file, the Open Liberty configuration is automatically reloaded.
Go to the http://localhost:9080/openapi/ui/ URL to see the OpenAPI user interface (UI) that provides API documentation and a client to test the API endpoints that you create after you see a message similar to the following example:
CWWKZ0001I: Application guide-mongodb-intro started in 5.715 seconds.Try the Create operation
From the OpenAPI UI, test the create operation at the POST /api/crew endpoint by using the following code as the request body:
{
"name": "Member1",
"rank": "Officer",
"crewID": "000001"
}This request creates a new document in the Crew collection with a name of Member1, rank of Officer, and crew ID of 000001.
You’ll receive a response that contains the JSON object of the new crew member, as shown in the following example:
{
"Name": "Member1",
"Rank": "Officer",
"CrewID": "000001",
"_id": {
"$oid": "<<ID>>"
}
}The <<ID>> that you receive is a unique identifier in the collection. Save this value for future commands.
Try the Retrieve operation
From the OpenAPI UI, test the read operation at the GET /api/crew endpoint. This request gets all crew member documents from the collection.
You’ll receive a response that contains an array of all the members in your crew. The response might include crew members that were created in the Try what you’ll build section of this guide:
[
{
"_id": {
"$oid": "<<ID>>"
},
"Name": "Member1",
"Rank": "Officer",
"CrewID": "000001"
}
]Try the Update operation
From the OpenAPI UI, test the update operation at the PUT /api/crew/{id} endpoint, where the {id} parameter is the <<ID>> that you saved from the create operation. Use the following code as the request body:
{
"name": "Member1",
"rank": "Captain",
"crewID": "000001"
}This request updates the rank of the crew member that you created from Officer to Captain.
You’ll receive a response that contains the JSON object of the updated crew member, as shown in the following example:
{
"Name": "Member1",
"Rank": "Captain",
"CrewID": "000001",
"_id": {
"$oid": "<<ID>>"
}
}Try the Delete operation
From the OpenAPI UI, test the delete operation at the DELETE/api/crew/{id} endpoint, where the {id} parameter is the <<ID>> that you saved from the create operation. This request removes the document that contains the specified crew member object id from the collection.
You’ll receive a response that contains the object id of the deleted crew member, as shown in the following example:
{
"_id": {
"$oid": "<<ID>>"
}
}Now, you can check out the microservice that you created by going to the http://localhost:9080/mongo/ URL.
Next, you’ll create integration tests to ensure that the basic operations you implemented function correctly.
Create theCrewServiceITclass.src/test/java/it/io/openliberty/guides/application/CrewServiceIT.java
CrewServiceIT.java
link:finish/src/test/java/it/io/openliberty/guides/application/CrewServiceIT.java[role=include]The test methods are annotated with the @Test annotation.
The following test cases are included in this class:
-
testAddCrewMember()verifies that new members are correctly added to the database. -
testUpdateCrewMember()verifies that a crew member’s information is correctly updated. -
testGetCrewMembers()verifies that a list of crew members is returned by the microservice API. -
testDeleteCrewMember()verifies that the crew members are correctly removed from the database.
You’ll see the following output:
-------------------------------------------------------
T E S T S
-------------------------------------------------------
Running it.io.openliberty.guides.application.CrewServiceIT
=== Adding 2 crew members to the database. ===
=== Done. ===
=== Updating crew member with id 5df8e0a004ccc019976c7d0a. ===
=== Done. ===
=== Listing crew members from the database. ===
=== Done. There are 2 crew members. ===
=== Removing 2 crew members from the database. ===
=== Done. ===
Tests run: 4, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.411 s - in it.io.openliberty.guides.application.CrewServiceIT
Results:
Tests run: 4, Failures: 0, Errors: 0, Skipped: 0Then, run the following commands to stop and remove the mongo-guide container and to remove the mongo-sample and mongo images.
docker stop mongo-guide
docker rm mongo-guide
docker rmi mongo-sampleYou’ve successfully accessed and persisted data to a MongoDB database from a Java microservice using Contexts and Dependency Injection (CDI) and MicroProfile Config with Open Liberty.
Learn more about MicroProfile.