Docker Mailcatcher using the latest Alpine Linux.
Status
License
Components & Versions
| component | version |
|---|---|
| Alpine Linux | 3.18.4 |
| MailCatcher | 0.9.0 |
| Ruby | 3.2.0 |
| SQLite | 3.43.1-r0 |
Ruby & SQlite versions may differ as they are updated during the installation of the image. A full list of the installed packages can be extracted using the following command docker exec -i <image_name> apk info -vv | sort
Supported Architectures
- x86_64
- arm64 (apple M1, etc.)
- x386, x86_32
- arm v8, v7 and v6
Should you need additional architecture, update the Dockerfile and submit your PR for review.
Latest version
Usage
Install it
Run docker pull stpaquet/alpinemailcatcher from Terminal to install the image on your computer.
Once the installation has completed with success you can run the following command docker images and you should see the following output (with more or less line depending on the number of containers already installed on your computer)
Pull / Upgrade
Pulling or upgrading to the latest version is done via
docker pull stpaquet/alpinemailcatcher:latest
How-to
A beginner guide to install Mailcatcher using a docker image and docker compose can be found here: https://medium.com/@spaquet/mailcatcher-to-the-rescue-4ba438dc98c2
Access Token
Docker users using 2FA might encounter the following error message: Error response from daemon: Head "https://registry-1.docker.io/v2/stpaquet/alpinemailcatcher/manifests/latest": unauthorized: please use personal access token to login
In that case they must follow the following procedure to set up an access token..
Once the access token created, they must login to their docker machine: docker login --username <username> and enter their access token when prompted.
Run it
There are different options when it comes to running this images. Here are our most favorite ones:
… and delete it right away
docker run --rm -p 1080:1080 -p 1025:1025 --name mailcatcher stpaquet/alpinemailcatcher
… as a daemon
docker run -d -p 1080:1080 -p 1025:1025 --name mailcatcher stpaquet/alpinemailcatcher
… change --messages-limit value
The default value is 50, but this value can be changed when launching the docker image using the following command: docker run -d -p 1080:1080 -p 1025:1025 -e MAIL_LIMIT=60 --name mailcatcher stpaquet/alpinemailcatcher
In the above example the value is raised to 60.
As this value is defined as an environment variable it can be modified in different ways, including using a docker-compose file.
… other environment variables and their default values
LANG=”en_US.UTF-8”
LC_ALL=”en_US.UTF-8”
LANGUAGE=”en_US.UTF-8”
TIMEZONE=”UTC”
All of the above variables can be changed at run time using the -e flag or included in a docker-compose file.
… Changing port (& running as a daemon)
In this version you cannot change the ports being used in the image. However, you can change the port translation.
If ports 1080 or 1025 are used by an other application or service on your computer you can change these values the following way:
docker run -d -p 3080:1080 -p 3025:1025 --name mailcatcher
Access it
Just point your favorite web browser to MailCatcher image IP address if on Linux or to docker-machine IP address if on a Mac or Windows PC.
When using Docker-Machine (Mac & Windows users)
On Mac and Windows you do not run docker directly, but through docker-machine. This implies that you will not access MailCatcher web interface using the IP address of the container, but the docker-machine one.
To get the IP address of your docker-machine run the following command:
docker-machine env dev (assuming your docker machine is named dev
export DOCKER_TLS_VERIFY="1"
export DOCKER_HOST="tcp://192.168.99.100:2376"
export DOCKER_CERT_PATH="/Users/username/.docker/machine/machines/dev"
export DOCKER_MACHINE_NAME="dev"
In this case, to access MailCatcher web interface you need to enter http://192.168.99.100:1080
Nota I
When using docker-machine do not forget to run eval $(docker-machine env dev) to configure your shell. If your shell is not properly configured you will not be able to run docker commands. Thus installing or running MailCatcher using this docker image will not work.
Nota II
Newer versions of docker desktop may not require the above when properly set up on a Mac as they properly bind to the localhost address of the machine being used.
Ruby on Rails (Rails)
Add the following lines to your environments/development.rb to redirect your ActionMailer directly to MailCatcher:
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = { address: '127.0.0.1', port: 1025 }
config.action_mailer.raise_delivery_errors = false
config.action_mailer.default_url_options = { host: "localhost", port: 3000 }
Make sure that the port and address are matching the one of your MailCatcher image, or docker-machine if you are on a Mac or PC running Windows.
Misc.
Other programming languages and frameworks are supported. Refer to their mailer documentation for their optimal configuration. But, since Mailcatcher is a leight weight SMTP server, most of the case limit to pointing to the local instance of Mailcatcher runnig in Docker and use the port 1025.
Known “issue”
MailCatcher is running in foreground mode. This does not change MailCatcher behavior and performances are not affected.
History
| Version | Date | Notes |
|---|---|---|
| 1.0 | 2017-08-07 | Initial release |
| 1.1 | 2017-08-08 | |
| 1.2 | 2022-02-27 | Updated to Mailcatcher 0.8 Limit to 50 the number of emails saved in mailcatcher |
| 1.3 | 2022-02-27 | Enable users to change mail-limit value at run time |
| 1.4 | 2022-02-28 | Upgrading to Mailcatcher 0.8.1 |
| 1.5 | 2022-03-03 | Tighter control over the environment |
| 1.6 | 2022-03-04 | Upgrading to Mailcatcher 0.8.2 |
| 1.7 | 2022-03-17 | Upgrading Alpine Linux to 3.15.1 Partial fix CVE-2022-0778 |
| 1.7.1 | 2022-03-17 | Removing unnecessary packages |
| 1.7.2 | 2022-03-17 | Removed a build layer |
| 1.7.3 | 2022-03-18 | Fixing CVE-2022-0778 once for all. In the previous versions, Libretls was outdated and offered a way to exploit CVE-2022-0778 |
| 1.7.4 | 2022-03-23 | Upgrading to Alpine Linux 3.15.2 which includes a fix for libretls CVE-2022-0778 and reverting to the default build process |
| 1.7.5 | 2022-03-31 | Upgrading to Alpine Linux 3.15.3 |
| 1.7.6 | 2022-04-05 | Upgrading to Alpine Linux 3.15.4 |
| 1.7.7 | 2022-05-25 | Upgrading to Alpine Linux 3.16.0 |
| 1.7.8 | 2022-05-30 | Fixing #5 - net-smtp was not properly loading when using ruby 3.1 |
| 1.7.9 | 2022-08-02 | Upgrading to Alpine Linux 3.16.1 - fix 2 major issues: busybox CVE-2022-30065 and openssl CVE-2022-2097. Alpine 3.16.1 detail change log can be found here |
| 1.7.10 | 2022-08-16 | Upgrading to Alpine Linux 3.16.2 |
| 1.7.11 | 2022-11-28 | Upgrading to Alpine Linux 3.17.0 and mailcatcher 0.9.0.beta1 |
| 1.8.1 | 2023-10-06 | Upgrading to Alpine Linux 3.18.4 and mailcatcher 0.9.0 |
| 1.8.2 | 2023-10-08 | Adding support to linux/arm64/v8 |
| 1.8.3 | 2023-10-09 | Fixing a bug affecting Mac M1 (and likely M2) |
Wanna contribute?
Fork and pull your changes!
To build run docker build -t stpaquet/alpinemailcatcher
Local build
git clone git@github.com:spaquet/docker-alpine-mailcatcher.git
cd docker-alpine-mailcatcher
docker run --rm -it -p 1080:1080 -p 1025:1025 --name mailcatcher $(docker build -q .)
Alpine MailCatcher @DockerHub
https://hub.docker.com/r/stpaquet/alpinemailcatcher
Alpine MailCatcher on GitHub
https://github.com/spaquet/docker-alpine-mailcatcher
Official MailCatcher sites
Github: https://github.com/sj26/mailcatcher
Website: https://mailcatcher.me/
Alpine Linux
Website: https://alpinelinux.org/