Skip to content

MariaDB

Since testcontainers-go v0.24.0

Introduction

The Testcontainers module for MariaDB.

Adding this module to your project dependencies

Please run the following command to add the MariaDB module to your Go dependencies:

go get github.com/testcontainers/testcontainers-go/modules/mariadb

Usage example

ctx := context.Background()

mariadbContainer, err := mariadb.RunContainer(ctx,
    testcontainers.WithImage("mariadb:11.0.3"),
    mariadb.WithConfigFile(filepath.Join("testdata", "my.cnf")),
    mariadb.WithScripts(filepath.Join("testdata", "schema.sql")),
    mariadb.WithDatabase("foo"),
    mariadb.WithUsername("root"),
    mariadb.WithPassword(""),
)
if err != nil {
    log.Fatalf("failed to start container: %s", err)
}

// Clean up the container
defer func() {
    if err := mariadbContainer.Terminate(ctx); err != nil {
        log.Fatalf("failed to terminate container: %s", err)
    }
}()

Module reference

The MariaDB module exposes one entrypoint function to create the MariaDB container, and this function receives two parameters:

func RunContainer(ctx context.Context, opts ...testcontainers.ContainerCustomizer) (*MariaDBContainer, error)
  • context.Context, the Go context.
  • testcontainers.ContainerCustomizer, a variadic argument for passing options.

Container Options

When starting the MariaDB container, you can pass options in a variadic way to configure it.

Tip

You can find all the available configuration and environment variables for the MariaDB Docker image on Docker Hub.

Image

If you need to set a different MariaDB Docker image, you can use testcontainers.WithImage with a valid Docker image for MariaDB. E.g. testcontainers.WithImage("mariadb:11.0.3").

Info

From MariaDB docs:

From tag 10.2.38, 10.3.29, 10.4.19, 10.5.10 onwards, and all 10.6 and later tags, the MARIADB_* equivalent variables are provided. MARIADB_* variants will always be used in preference to MYSQL_* variants.

The MariaDB module will take all the environment variables that start with MARIADB_ and duplicate them with the MYSQL_ prefix.

Image Substitutions

In more locked down / secured environments, it can be problematic to pull images from Docker Hub and run them without additional precautions.

An image name substitutor converts a Docker image name, as may be specified in code, to an alternative name. This is intended to provide a way to override image names, for example to enforce pulling of images from a private registry.

Testcontainers for Go exposes an interface to perform this operations: ImageSubstitutor, and a No-operation implementation to be used as reference for custom implementations:

// ImageSubstitutor represents a way to substitute container image names
type ImageSubstitutor interface {
    // Description returns the name of the type and a short description of how it modifies the image.
    // Useful to be printed in logs
    Description() string
    Substitute(image string) (string, error)
}

type NoopImageSubstitutor struct{}

// Description returns a description of what is expected from this Substitutor,
// which is used in logs.
func (s NoopImageSubstitutor) Description() string {
    return "NoopImageSubstitutor (noop)"
}

// Substitute returns the original image, without any change
func (s NoopImageSubstitutor) Substitute(image string) (string, error) {
    return image, nil
}

Using the WithImageSubstitutors options, you could define your own substitutions to the container images. E.g. adding a prefix to the images so that they can be pulled from a Docker registry other than Docker Hub. This is the usual mechanism for using Docker image proxies, caches, etc.

WithEnv

If you need to either pass additional environment variables to a container or override them, you can use testcontainers.WithEnv for example:

postgres, err = postgresModule.RunContainer(ctx, testcontainers.WithEnv(map[string]string{"POSTGRES_INITDB_ARGS": "--no-sync"}))

WithHostPortAccess

If you need to access a port that is already running in the host, you can use testcontainers.WithHostPortAccess for example:

postgres, err = postgresModule.RunContainer(ctx, testcontainers.WithHostPortAccess(8080))

To understand more about this feature, please read the Exposing host ports to the container documentation.

WithLogConsumers

If you need to consume the logs of the container, you can use testcontainers.WithLogConsumers with a valid log consumer. An example of a log consumer is the following:

type TestLogConsumer struct {
    Msgs []string
}

func (g *TestLogConsumer) Accept(l Log) {
    g.Msgs = append(g.Msgs, string(l.Content))
}

WithLogger

If you need to either pass logger to a container, you can use testcontainers.WithLogger.

Info

Consider calling this before other "With" functions as these may generate logs.

In this example we also use TestLogger which writes to the passed in testing.TB using Logf. The result is that we capture all logging from the container into the test context meaning its hidden behind go test -v and is associated with the relevant test, providing the user with useful context instead of appearing out of band.

func TestHandler(t *testing.T) {
    logger := TestLogger(t)
    _, err := postgresModule.RunContainer(ctx, testcontainers.WithLogger(logger))
    require.NoError(t, err)
    // Do something with container.
}

Please read the Following Container Logs documentation for more information about creating log consumers.

Wait Strategies

If you need to set a different wait strategy for the container, you can use testcontainers.WithWaitStrategy with a valid wait strategy.

Info

The default deadline for the wait strategy is 60 seconds.

At the same time, it's possible to set a wait strategy and a custom deadline with testcontainers.WithWaitStrategyAndDeadline.

Startup Commands

Testcontainers exposes the WithStartupCommand(e ...Executable) option to run arbitrary commands in the container right after it's started.

Info

To better understand how this feature works, please read the Create containers: Lifecycle Hooks documentation.

It also exports an Executable interface, defining the following methods:

  • AsCommand(), which returns a slice of strings to represent the command and positional arguments to be executed in the container;
  • Options(), which returns the slice of functional options with the Docker's ExecConfigs used to create the command in the container (the working directory, environment variables, user executing the command, etc) and the possible output format (Multiplexed).

You could use this feature to run a custom script, or to run a command that is not supported by the module right after the container is started.

Ready Commands

Testcontainers exposes the WithAfterReadyCommand(e ...Executable) option to run arbitrary commands in the container right after it's ready, which happens when the defined wait strategies have finished with success.

Info

To better understand how this feature works, please read the Create containers: Lifecycle Hooks documentation.

It leverages the Executable interface to represent the command and positional arguments to be executed in the container.

You could use this feature to run a custom script, or to run a command that is not supported by the module right after the container is ready.

WithNetwork

By default, the container is started in the default Docker network. If you want to use an already existing Docker network you created in your code, you can use the network.WithNetwork(aliases []string, nw *testcontainers.DockerNetwork) option, which receives an alias as parameter and your network, attaching the container to it, and setting the network alias for that network.

In the case you need to retrieve the network name, you can simply read it from the struct's Name field. E.g. nw.Name.

Warning

This option is not checking whether the network exists or not. If you use a network that doesn't exist, the container will start in the default Docker network, as in the default behavior.

WithNewNetwork

If you want to attach your containers to a throw-away network, you can use the network.WithNewNetwork(ctx context.Context, aliases []string, opts ...network.NetworkCustomizer) option, which receives an alias as parameter, creating the new network with a random name, attaching the container to it, and setting the network alias for that network.

In the case you need to retrieve the network name, you can use the Networks(ctx) method of the Container interface, right after it's running, which returns a slice of strings with the names of the networks where the container is attached.

Docker type modifiers

If you need an advanced configuration for the container, you can leverage the following Docker type modifiers:

  • testcontainers.WithConfigModifier
  • testcontainers.WithHostConfigModifier
  • testcontainers.WithEndpointSettingsModifier

Please read the Create containers: Advanced Settings documentation for more information.

Customising the ContainerRequest

This option will merge the customized request into the module's own ContainerRequest.

container, err := RunContainer(ctx,
    /* Other module options */
    testcontainers.CustomizeRequest(testcontainers.GenericContainerRequest{
        ContainerRequest: testcontainers.ContainerRequest{
            Cmd: []string{"-c", "log_statement=all"},
        },
    }),
)

The above example is updating the predefined command of the image, appending them to the module's command.

Info

This can't be used to replace the command, only to append options.

Set username, password and database name

If you need to set a different database, and its credentials, you can use WithUsername, WithPassword, WithDatabase options.

Info

The default values for the username is root, for password is test and for the default database name is test.

Init Scripts

If you would like to perform DDL or DML operations in the MariaDB container, add one or more *.sql, *.sql.gz, or *.sh scripts to the container request, using the WithScripts(scriptPaths ...string). Those files will be copied under /docker-entrypoint-initdb.d.

CREATE TABLE IF NOT EXISTS profile (
    id MEDIUMINT NOT NULL AUTO_INCREMENT,
    name VARCHAR(30) NOT NULL,
    PRIMARY KEY (id)
);

INSERT INTO profile (name) values ('profile 1');

Custom configuration

If you need to set a custom configuration, you can use WithConfigFile option to pass the path to a custom configuration file.

Container Methods

The MariaDB container exposes the following methods:

ConnectionString

This method returns the connection string to connect to the MariaDB container, using the default 3306 port. It's possible to pass extra parameters to the connection string, e.g. tls=false, in a variadic way.

Info

By default, MariaDB transmits data between the server and clients without encrypting it.

    // By default, MariaDB transmits data between the server and clients without encrypting it.
    connectionString, err := container.ConnectionString(ctx, "tls=false")

 ⋯

        t.Errorf("ConnectionString was not equal to MustConnectionString")