MockServer is available as a docker container that allows you to easily run MockServer as a separate container on any environment without having to install Java or any other libraries. The docker container fully encapsulates all requirements required to run MockServer (such as Java) and separates the running MockServer instance from all other parts of the system.

MockServer docker container can be found at MockServer Docker

Running MockServer Docker Container

The typical sequence for running the MockServer docker image is as follows:
  1. Install Docker
  2. Pull (or Update) Image
  3. Run Container
In addition it is possible to customise how the container is run.  

Install Docker

To install Docker see the installation instructions.

 

Pull MockServer Image

To pull the MockServer Docker image use the pull command, as follows:

docker pull mockserver/mockserver

This is not strictly necessary as the image will be automatically pulled if it does not exist when the run command is used. However, using the pull command will ensure the latest version of the image is downloaded.

 

Run MockServer Container

Then to run MockServer as a Docker container run the following command:

docker run -d --rm -P mockserver/mockserver

The -P switch in this command tells Docker to map all ports exported by the MockServer container to dynamically allocated ports on the host machine.

To view information about the MockServer container, including which dynamic ports have been used run the following command:

docker ps

No Interactive Shell

MockServer uses distroless as its based container for both size and security and so does not contain an interactive shell. This minimises the likelihood of vulnerabilities and to reduces the attack surface by ensuring only the JVM and MockServer code is inside the container.

   

Configure Port Mapping

This MockServer docker container exports the following port:

  • serverPort 1080

To specify which ports (on the host machine) should be mapped to the MockServer docker container use the -p <host port>:<container port> option, as follows:

docker run -d --rm -p <serverPort>:1080 mockserver/mockserver

For example:

docker run -d --rm -p 1080:1080 mockserver/mockserver
 

Environment Variables

It is possible configure MockServer behaviour through environment variables, this includes port mappings, log level and lots of other properties for example:

docker run -d --rm -p 1090:1090 --env MOCKSERVER_LOG_LEVEL=TRACE --env MOCKSERVER_SERVER_PORT=1090 mockserver/mockserver
 

Modifying Default Command

By default when the MockServer container runs it executes a bash script passing three command line options, as follows

-logLevel INFO -serverPort 1080

This can be modified to change the command line options passed to the MockServer for example:

docker run --rm --name mockserver -p 1080:1090 mockserver/mockserver -logLevel INFO -serverPort 1090 -proxyRemotePort 443 -proxyRemoteHost mock-server.com

Detailed MockServer Configuration

To support configuring MockServer a mockserver.properties will be loaded from /config directory if it exists.

A mockserver.properties configuration file and other related configuration files such as json expectation initialization, or custom TLS CA, X.509 Certificate or Private Key should be mapping into the /config directory.

For example to add configuration files in the current directory, such as mockserver.properties, map $(pwd) into /config, as follows: 
docker run -v $(pwd):/config -p 1080:1080  mockserver/mockserver -serverPort 1080

See MockServer Configuration for details of all configuration options.

As the Docker image is based from gcr.io/distroless/java:11 and the user nonroot is used, we need to configure permissions in order to allow the user in the container read/write files in mounted volumes: 
chmod o+r $(pwd)/mockserver.properties
 

Extending MockServer Classpath

To use class callbacks or an expectation initializer class the classpath for MockServer must include the specified classes.

To support adding classes to the classpath any jar files contained in the /libs directory will be added into MockServer classpath.

For example to add all jar files in the current directory, map $(pwd) into /libs, as follows: 
docker run -v $(pwd):/libs -p 1080:1080  mockserver/mockserver -serverPort 1080
 

Docker Compose

MockServer can be run using docker compose by adding the container as a service.

The MockServer container uses an entrypoint, so it is possible to configure the MockServer by specifying the command line flags using by specifying the command, as follows:

version: "2.4"
services:
  mockServer:
    image: mockserver/mockserver:5.14.0
    command: -logLevel DEBUG -serverPort 1090 -proxyRemotePort 80 -proxyRemoteHost www.mock-server.com
    ports:
      - 1080:1090

It is also possible to configure the MockServer by setting environment variables, as follows:

version: "2.4"
services:
  mockServer:
    image: mockserver/mockserver:5.14.0
    ports:
      - 1080:1090
    environment:
      MOCKSERVER_MAX_EXPECTATIONS: 100
      MOCKSERVER_MAX_HEADER_SIZE: 8192

It is also possible to configure the MockServer by mounting a volume containing a properties file or JSON expectation initializer, as follows:

version: "2.4"
services:
  mockServer:
    image: mockserver/mockserver:5.14.0
    ports:
      - 1080:1080
    environment:
      MOCKSERVER_PROPERTY_FILE: /config/mockserver.properties
      MOCKSERVER_INITIALIZATION_JSON_PATH: /config/initializerJson.json
    volumes:
      - type: bind
        source: .
        target: /config