testcontainers docker images

Check your inbox or spam folder to confirm your subscription. You are sure that your application is correctly packed as a docker image, so another layer of application is tested. Functional tests implemented in this way are not for everybody. It gives developers a lot of confidence that the code does what it should do. ", // 'src' is expected to be the project base directory, so all source code/resources should be copied in, "cat /foo/test/resources/test-recursive-file.txt". This has caused some ambiguity and confusion. For example, if we call a REST endpoint, send plain JSON and read JSON. Map a resource (file or directory) on the classpath to a path inside the container. So, we need to run it once for all tests. It really depends on your testing strategy. Because functional tests are running services and dependencies (like database, queues) as docker images, we need to run it at least once. I find it very useful during code refactoring. Compare Couchbase pricing or ask a question. It can be pretty expensive to implement it, but it also gives you big confidence that a system still works during deep refactoring. Follow container output, sending each frame (usually, line) to a consumer. Laurent Doguin, Developer Advocate, Couchbase, how to do unit and integration tests with Couchbase and TestContainers, Reflecting on the BASE IPO One Year Later, Couchbase vs MongoDB: NoSQL Misconceptions Part 4, Do More With Couchbase Capella on 6 Nodes Than MongoDB Atlas on 18 Nodes, Introducing the Couchbase Ambassador Program, Oracle Date Format: N1QL and Support for Date-Time Functions Pt 1, 11 Fluent Bit Tips & Tricks for Log Forwarding with Couchbase, Converting XML to JSON In C# Using Json.NET. If there are changes to the storage of the service in the future, we would need to change our tests. Learn about Couchbase's ISV Program and how to join. There are many definitions of functional testing. To do this, create or modify a file on the classpath named testcontainers.properties. i.e. String dockerFile = IOUtils.toString(ElasticsearchContainer. In the @SpringBootTest annotation I added the TestContainerConfig class, to include the testcontainer configuration in the application context. In this post I am going to discuss about the database factor. We should operate on the simplest possible interfaces. String results = toString.toUtf8String(); "The container has a file that was copied in via a recursive copy", // This test combines the copying of classpath resources from JAR files with the recursive TAR approach, to allow JARed classpath resources to be copied in to an image, // here we use /org/junit as a directory that really should exist on the classpath, // ExternalResource.class is known to exist in a subdirectory of /org/junit so should be successfully copied in, "The container has a file that was copied in via a recursive copy from a JAR resource", "while true; do cat /someFile.txt | nc -l -p 80; done". Add an environment variable to be passed to the container. We're here to help. Get certified and bring your Couchbase knowledge to the database market. What is the key difference between non-functional software testing and functional testing? Without it, you are loosing visibility on errors. tests have run. Functional testing is conducted to evaluate the compliance of a system or component with specified functional requirements. Couchbase is JSON database that excels in high volume transactions. Instead, it is highly recommended that all containers be constructed using a constructor that accepts a DockerImageName object. Functional tests are not answering the question of HOW it works internally, but rather WHAT the result should be. Attach an output consumer at container startup, enabling stdout and stderr to be followed, waited on, etc. Set the ports that this container listens on, Add an extra host entry to be passed to the container. This is why I use the withFileFromClasspath method. It is critical that tests use different object identifiers and that there is a clean state after the test. Another comparison you might see when discussing this is black-box testing vs white-box testing. You can have a chat with them on their Slack channel, just like you can have a chat with Couchbase folks on our community channel. i.e. Laurent is a Paris based Developer Advocate where he focuses on helping Java developers and the French community. You can find an introduction to the TestContainers library in my previous article Integration tests with Testcontainers, because that is out of the scope of this one. Set the command that should be run in the container. The testing method uses many helper methods to simplify the test. // populate map, e.g. Note that it is also possible to provide this same configuration property: Please see the documentation on configuration mechanisms for more information. redis, elasticsearch, mongo), Other services developed by your team/organization which are already dockerized. " Testcontainers is a Java library that supports JUnit tests, providing lightweight, throwaway instances of common databases, Selenium web browsers, or anything else that can run in a Docker container. " name of a Docker Hub image dependency with an alternative hosted on a private image registry. For example, non-Hub image names (e.g. We could create the entity directly inside the database and inside the test to just retrieve it, but it would not be a black-box test then. To achieve this: The structure of invocation can look like below. For what is possible, consult the docker-java CreateContainerCmd source code. Trying to hit localhost Turns out you dont have too. I recommend using only official interfaces to create resources, e.g. Because we dont have access to the service code, we cannot use any DTO objects, database repositories, etc. An input stream that reads bytes from a file. Worth mentioning that by design the host port will always be a random one, to avoid conflicts with other application running; to get access to the host port we need to use: In the sql script, I am making a new table and inserting some data: Now when run the test, we can see the following log: At the first time the image will be pulled from the public docker registry (make sure that your are logged into your registry if needed with 'docker login link'). The intention of functional testing is to verify software actions, and non-functional testing validates the behavior of the application. : Many Container classes in Testcontainers have historically supported: Since v1.15.0, both of these constructor types have been deprecated, for the reasons given above. This method allows Stdout and/or stderr You also need to remember that a proper pyramid of tests is (when sorted from the highest to the lowest amount of tests): It is very nice to have functional tests, but it cannot dominate your testing structure. Running a lottery? File file = finally Prior to joining Couchbase he was Nuxeos community liaison where he devoted his time and expertise to helping the entire Nuxeo Community become more active and efficient. For example, if you might use it to test interactions with: With a generic container, you set the container image using a parameter to the rule constructor, e.g. The order An example functional test can look like below. Any customizations you make using withCreateContainerCmdModifier will be applied on top of the container definition that Testcontainers creates, but before it is created. Capella, Atlas, DynamoDB evaluated on 40 criteria. Functional testing verifies what the system should do, and non-functional testing tests how well the system works. For example, the definition found on Wikipedia is: Functional testing is a quality assurance (QA) process and a type of black-box testing that bases its test cases on the specifications of the software component under test. If functional tests are written in a bad way, they can make tests interfere with each other. One of the prerequisite for those tests was to have an image already built. As an alternative solution, I would suggest the creation of a Junit5 extension. White-box testing is aware of the internal structures. Stdout and stderr will be followed. Copies a file or directory to the container. This just listens on port 80, "while true; do echo \"$MAGIC_NUMBER\" | nc -l -p 80; done", Creating a generic container based on an image, Networking and communicating with containers, Waiting for containers to start or be ready, Patterns for running tests inside a Docker container, CircleCI (Cloud, Server v2.x, and Server v3.x), NoSQL databases or other data stores (e.g. We are able to test the service as black-box, meaning that when you have a good functional tests coverage, you are able to make a deep refactoring without changing functional tests. Zalando uses it mainly for integration and functional tests. It is possible to specify an Image Pull Policy to determine at runtime whether an image should be pulled or not: It is possible to use the docker-java API directly to customize containers before creation. to be selected. It's Testcontainers. We want to start a postgres container with some initialized data, when we launch the test. you would leave as-is: You can then configure Testcontainers to apply the prefix registry.mycompany.com/mirror/ to every image that it tries to pull from Docker Hub. the machine on which this test is running. This allows replacement of an image name specified in test code with an alternative name - for example, to replace the Class to hold results from a "docker exec" command. Black-box testing looks at the functionality of the software without looking at the internal structures. You can create your own images just before running your tests and it is super easy. Only consider a container to have successfully started if it has been running for this duration. Yesterday I wrote about how to do unit and integration tests with Couchbase and TestContainers. It is typically quite stable, though. browsers) can use to reference a service running on the local machine, By default the images are deleted on exit but you can pass a flag to keep the images and avoid rebuilding them all the time. The default The functional-tests module cannot have any dependency on the service module. The answer is relatively simple: non-functional testing is concerned with how, and functional testing is concerned with what. This is advisable to avoid Docker Hub rate limiting, and some companies will prefer this for policy reasons. i.e. Thats why I additionally specify shutdownHook, which stops all docker images when test execution finishes. In this case, image name references in code are left unchanged. Here I have copied all I needed into the resources folder of my project, which make them all accessible form the classpath. But if you run docker images from multiple maven modules, the Ryuk image can be too slow and the build can crash. Consult the documentation for your desired one. value is null; if that's the value, ignore this check. Don't forget adding a logger to the container code: One of the biggest advantages of the TestContainers library is the fact that there is a Ryuk container that stops all other containers when an initial JVM process is terminated. * IsEmpty/IsBlank - checks if a String contains, ParameterizedDockerfileContainerTest(String baseImage, String expectedVersion) {, ().withDockerfileFromBuilder(builder -> {, // Could potentially customise the image here, e.g. Your entire production code needs to be packaged and run as a docker image. : non-deterministic mapping of names meaning that a, rules depending upon developer identity or location, or you wish to add audit logging of images used in the build, or you wish to prevent accidental usage of images that are not on an approved list, configuring Testcontainers to use your custom implementation, in a properties file in the user's home directory (, You have many references to image names in code and changing them is impractical, and, None of the other options are practical for you. Which happens to be what the ImageFromDockerfile class is. In this article, I will show how teams at Zalando Marketing Services are using functional tests. Usually, it is slow. This approach simply entails modifying test code manually, e.g. Add environment variables to be passed to the container. This works well when running against a specific version, but for images with a static tag (i.e. where another registry is set), Docker Hub image names where the hub registry is explicitly part of the name (i.e. Your private registry has copies of images from Docker Hub where the names are predictable, and just adding a prefix is enough. Packaging your application into a docker image is pretty simple. Functional testing usually describes what the system does.. 'latest') this may lead to a newer version not being pulled. Set the duration of waiting time until container treated as started. Functional tests answer the fundamental question: Do the features work as intended? Run a command inside a running container, as though using "docker exec". mapOfLabels.put("key1", "value1"); Networking and communicating with containers, Waiting for containers to start or be ready, Patterns for running tests inside a Docker container, CircleCI (Cloud, Server v2.x, and Server v3.x). In this case, image name references in code are unchanged. You can find examples of usages in my GitLab project. Especially when something doesnt work as expected, debugging becomes much harder. Spin up your database container during integration testing using #springboot #testcontainers #docker https://t.co/kxf29i3oUW, "UPDATE POST SET title='first' WHERE id=1". Besides of high cost of development, it gives us a very high confidence level that the delivered applications are working as intended. A generic container rule can be used with any public docker image; for example: These containers, as @ClassRules, will be started before any tests in the class run, and will be destroyed after all Testcontainers Then, we will discuss an example based on the TestContainers library used in the Spring environment. Follow container output, sending each frame (usually, line) to a consumer. This can be done in one of two ways: Testcontainers will automatically apply the prefix to every image that it pulls from Docker Hub - please verify that all the required images exist in your registry. It would place you in the position of a real client of your service. But the GenericContainer constructor also accepts a Future. Copies a file which resides inside the container to user defined directory, Streams a file which resides inside the container. Testcontainers supports automatic substitution of Docker image names. Functional tests give you a lot of confidence that the application works as expected. I recommend organizing code into a multi-module maven project with two modules: service and functional-tests. the output as UTF8. HostPortWaitStrategy().withRateLimiter(RateLimiters.TWENTIES_PER_SECOND)). When running the docker image with our service, it is critical to add logging. Many developers use an embedded db or an actual one deployed on the development server, but Docker containers are the best way to have an isolated database locally, there is an image for almost every database, PostgreSQL, Oracle, MongoDb, etc. Testcontainers will not apply the prefix to: You can implement a custom image name substitutor by: The following is an example image substitutor implementation: Testcontainers can be configured to find it at runtime via configuration. Map a resource (file or directory) on the classpath to a path inside the container. In "withInitScript" we indicate the initial sql script to be run into the database. Goal And with that, your Docker image will be built automatically before running your tests. images as temporary test dependencies. When arrives the time to perform an integration test to our microservice, the best choice is to make it in an isolated environment extremely similar to the production one. Testcontainers' generic container support offers the most flexibility, and makes it easy to use virtually any container I find functional tests to be an interesting concept. Consider using. The Docker image will be created asynchronously with the parameters you will give. There are many other modules, like MongoDb, Oracle, etc. Weve got you covered. This is now a known issue and the lovely and reactive people behind TestContainer are working on this. create entities via the REST interface. Pfizer deployed Couchbase AWS for high performance and flexibility for dozens of healthcare applications. This is useful if there is a need to use advanced Docker features that are not exposed by the Testcontainers API. And finally the datasource bean is defined. We explore how to write functional tests using Testcontainers.org library in Java-based backend applications. adding files, running, // Using a Dockerfile here, since Dockerfile builder DSL doesn't support HEALTHCHECK, "health-wait-strategy-dockerfile/write_file_and_loop.sh", "health-wait-strategy-dockerfile/Dockerfile", .waitingFor(Wait.forHealthcheck().withStartupTimeout(Duration.ofSeconds(, "Listing shows that file is copied with mode requested. TestContainer configuration Set the command that should be run in the container. You can also get a File from a String, an absolute path or a file. POM All functional tests extend the AbstractFunctionalTest class where all needed docker images are run. Consider using, Adds a file system binding. Overriding individual image names via configuration may be removed in the future. Testcontainers.org is a JVM library that allows users to run and manage docker images and control them from Java code. Consider using, Add an environment variable to be passed to the container. The biggest advantages of functional tests are: Unit tests force developers to think about methods. To add a custom label to the container, use withLabel: Additionally, multiple labels may be applied together from a map: By default, the container image is retrieved from the local Docker images cache. Writing functional tests can be time-consuming. Functional tests do the same for applications/components. Please consider one of the other approaches outlined in this page instead. in.clos, KeyStore is responsible for maintaining cryptographic keys and their owners. a single string-argument constructor, which has taken either a version or an image name as a String. changing: For example, you may have a test that uses the mysql container image from Docker Hub: Testcontainers can be configured to modify Docker Hub image names on the fly to apply a prefix string. Set the network for this container, similar to the, Set the network aliases for this container, similar to the, Set the network mode for this container, similar to the, Set the privilegedMode mode for the container. is determined eithe, Operations on java.lang.String that arenull safe. The configuration class is extremely simple: We could annotate the class with @Configuration, but we already included it with: We use the @ClassRule to get an isolated container for all the methods in the test class (you can also remove it, it's necessary if you start the container in the test class). The main purpose of functional tests with the Testcontainers library is to set up a black-box test, by using an environment closest to the production one. All the resources that were used for the image creation lost their permissions, so I had to add a RUN chmod +x on all the resources I copy in the Dockerfile. Youll find more informations about this on TestContainers documentation. In this demo I am making an integration test to an spring boot application with postgreSQL as a database. Get the IP address that containers (e.g. If your service needs to communicate to the database, you need to run the database as a docker image as well. For example, this can be used to change the container hostname: or modify container memory (see this if it does not appear to work): It is recommended to use this sparingly, and follow changes to the docker-java API if you choose to use this. Your functional tests will test your code ran as a docker image, so your testing code does not have any connection to production code. to be pointed at "http://" + getTestHostIpAddress() + ":8080" in order to access it. This approach is discouraged and deprecated, but is documented for completeness. I would suggest having it in the systems where microservice contracts are not changing very fast. For the testcontainers lib, you can see the specific targeted module under "postgresql" artifactId and the actual library under "testcontainers". "/accounts/00000000-0000-0000-0000-000000000001". It protects us from unwanted zombie containers (and networks, volumes) in the system. anything with a. In the PostgreSQLContainer constructor we added the docker image which will be used, in this case, it's a postgres:9.6.18-alpine. You can write scripts to run the container, when you launch the integaration test (with all parameters needed), you can do it manually; but why do all this stuff by your self, if there is a great open source library for Java projects that do exactly this work and more. Functions are tested by feeding them input and examining the output, and internal program structure is rarely considered (unlike white-box testing). If you would like to help us improve our tests and thus help shipping high-quality features for our customers, please consider joining our Engineering Teams at Zalando Marketing Services (ZMS). 2022 Couchbase, Inc. Couchbase, Couchbase Lite and the Couchbase logo are registered trademarks of Couchbase, Inc. Couchbase Server 4.1.0 CE is now available! you would leave as-is: You can force Testcontainers to substitute in a different image using a configuration file, which allows some (but not all) container names to be substituted. He writes code in Java and blog posts in Markdown. The DockerImageName class is an unambiguous reference to a docker image. if (in != null) I will focus mainly on the test package and the configuration needed to launch a postgres container with the test. In the root of your repository, just define Dockerfile like: As an alternative solution, I would suggest using Jib. For more details about all the possible configuration, you can consult the docs. Set the startup check strategy used for checking whether the container has started. Dont create any internal DTOs. This will only work if you are running your tests outside a Docker container. Run a command inside a running container, as though using "docker exec", and interpreting For example, if a web server is running on port 8080 on this local machine, the containerized web driver needs There are many other features, for example we could execute commands in the container with "execInContainer" parameter. While writing this I encountered a minor issue. Follow container output, sending each frame (usually, line) to a consumer. The container will be stopped and removed when the application exits. Set the command that should be run in the container, Set the file to be copied before starting a created container. In an ideal world, we should run new containers for each test, but it would be way too slow. It is a standard pom.xml generated from Spring Initializr: We have the driver and the starter-jdbc dependency to perform some queries. We will follow the idea of functional tests: the main concept and the attributes of a good functional test. from inside the container is not going to work, since the container has its own IP address. SpamAssassinWaitStrategy(spamAssassinContainer)); SwarmGenericContainer createContainer() {. In the previous example an image would be instanciated with the following code: The GenericContainer constructor would just take a String as parameter. You have complex rules about which private registry images should be used as substitutes, e.g. Thanks to Sergei Egorov for showing me the way! Only consider a container to have successfully started if it has been running for this duration. // Set up a plain OS container and customize environment, // command and exposed ports. Retailing on Black Friday? It is suggested that developers treat DockerImageNames as you would any other potentially-constant value - consider defining a constant in your test codebase that matches the production version of the dependency you are using. In the following integration test, we are making two checks, the first one to enure that our data is actually there and the second one is just an update. This page describes four approaches for image name substitution: It is assumed that you have already set up a private registry hosting all the Docker images your build requires. In our example, I will run my microservice which is connected to the database. In this case, we would use an annotation instead inheritance, with the same logic. From a different point of view, if you have well-written helper classes you can speed up this process. The TestContainers library makes it possible to use this concept inside the Java world. To have all the data related to the container, first we need to start it and then we set all the parameters. "Starting an elasticsearch container using version [{}] from [{}]", // We need to map the local dir which contains plugins with the container. For example: PostgreSQL as a docker image needs around 4 seconds to start on my machine, Localstack which emulates AWS components, can take much longer to start, even 20 seconds.