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Mailpit

Not available until the next release main

Introduction

The Testcontainers module for Mailpit.

Mailpit is a fast, multi-platform email testing tool. It provides an SMTP server that captures outgoing emails and exposes them through a web UI and REST API, making it ideal for asserting email sending behaviour in integration tests.

Adding this module to your project dependencies

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

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

Usage example

ctx := context.Background()

mailpitContainer, err := mailpit.Run(ctx, "axllent/mailpit:v1.20")
defer func() {
    if err := testcontainers.TerminateContainer(mailpitContainer); err != nil {
        log.Printf("failed to terminate container: %s", err)
    }
}()
if err != nil {
    log.Printf("failed to start container: %s", err)
    return
}

Module Reference

Run function

  • Not available until the next release main

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

func Run(ctx context.Context, img string, opts ...testcontainers.ContainerCustomizer) (*Container, error)
  • context.Context, the Go context.
  • string, the Docker image to use.
  • testcontainers.ContainerCustomizer, a variadic argument for passing options.

Image

Use the second argument in the Run function to set a valid Docker image. In example: Run(context.Background(), "axllent/mailpit:v1.20").

Container Options

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

WithSMTPAuth

  • Not available until the next release main

WithSMTPAuth sets the SMTP authentication credentials for the Mailpit container via the MP_SMTP_AUTH environment variable (in user:password format), and enables plaintext authentication via MP_SMTP_AUTH_ALLOW_INSECURE.

ctr, err := mailpit.Run(ctx, "axllent/mailpit:v1.20",
    mailpit.WithSMTPAuth("user", "password"),
)

WithMessageLimit

  • Not available until the next release main

WithMessageLimit sets the maximum number of messages to store in Mailpit, using the MP_MAX_MESSAGES environment variable. When the limit is reached the oldest messages are automatically deleted.

ctr, err := mailpit.Run(ctx, "axllent/mailpit:v1.20",
    mailpit.WithMessageLimit(100),
)

The following options are exposed by the testcontainers package.

Basic Options

Lifecycle Options

Files & Mounts Options

Build Options

Logging Options

Image Options

Networking Options

Advanced Options

Experimental Options

Container Methods

The Mailpit container exposes the following methods:

SMTPEndpoint

  • Not available until the next release main

SMTPEndpoint returns the host:port connection string for the Mailpit SMTP server, using the 1025 port.

smtpEndpoint, err := ctr.SMTPEndpoint(ctx)

HTTPURL

  • Not available until the next release main

HTTPURL returns the URL for the Mailpit web interface and REST API, using the 8025 port. The REST API is available at /api/v1/messages and other endpoints under /api/v1/.

httpURL, err := ctr.HTTPURL(ctx)