Bamboo

Flexible and easy to use email for Elixir.

• Adapter based so it can be used with Mandrill, SMTP, or whatever else you want. Comes with a Mandrill adapter out of the box.
• Deliver emails in the background. Most of the time you don’t want or need to wait for the email to send. Bamboo makes it easy with Mailer.deliver_later
• Easy to format recipients. You can do new_email(to: Repo.one(User)) and Bamboo can format the User struct if you implement Bamboo.Formatter.
• Works out of the box with Phoenix. Use views and layouts to make rendering email easy.
• Very composable. Emails are just a Bamboo.Email struct and can be manipulated with plain functions.
• Easy to unit test. Because delivery is separated from email creation, no special functions are needed, just assert against fields on the email.
• Easy to test delivery in integration tests. Helpers are provided to make testing easy and robust.
• Preview sent emails during development. Bamboo comes with a plug that can be used in your router to preview sent emails.

See the docs for the most up to date information.

We designed Bamboo to be simple and powerful. If you run into anything that is less than exceptional, or you just need some help, please open an issue.

Adapters

The Bamboo.MandrillAdapter and Bamboo.SendgridAdapter are being used in production and have had no issues. It’s also pretty simple to create your own adapter. Feel free to open an issue or a PR if you’d like to add a new adapter to the list.

• Bamboo.MailgunAdapter - Ships with Bamboo. Thanks to @princemaple.
• Bamboo.MandrillAdapter - Ships with Bamboo.
• Bamboo.SendgridAdapter - Ships with Bamboo.
• Bamboo.SMTPAdapter - See fewlinesco/bamboo_smtp.
• Bamboo.SparkPostAdapter - See andrewtimberlake/bamboo_sparkpost.
• Bamboo.LocalAdapter - Ships with Bamboo. Stores email in memory. Great for local development.
• Bamboo.TestAdapter - Ships with Bamboo. Use in your test environment.

To switch adapters, change the config for your mailer:

# In your config file
config :my_app, MyApp.Mailer,
  adapter: Bamboo.LocalAdapter

Installation

1. Add bamboo to your list of dependencies in mix.exs:

  def deps do
    # Get from hex
    [{:bamboo, "~> 0.6"}]
    # Or use the latest from master
    [{:bamboo, github: "thoughtbot/bamboo"}]
  end

1. Ensure bamboo is started before your application:

  def application do
    [applications: [:bamboo]]
  end

Getting Started

Do you like to learn by watching? Check out the free Bamboo screencast from DailyDrip.

It is a wonderful introduction to sending and testing emails with Bamboo. It also covers some of the ways that Bamboo helps catch errors, how some of the internals work, and how to format recipients with the Bamboo.Formatter protocol.

Bamboo breaks email creation and email sending into two separate modules. This is done to make testing easier and to make emails easy to pipe/compose.

# In your config/config.exs file
config :my_app, MyApp.Mailer,
  adapter: Bamboo.MandrillAdapter,
  api_key: "my_api_key"

# Somewhere in your application
defmodule MyApp.Mailer do
  use Bamboo.Mailer, otp_app: :my_app
end

# Define your emails
defmodule MyApp.Email do
  import Bamboo.Email

  def welcome_email do
    new_email(
      to: "john@gmail.com",
      from: "support@myapp.com",
      subject: "Welcome to the app.",
      html_body: "<strong>Thanks for joining!</strong>",
      text_body: "Thanks for joining!"
    )

    # or pipe using Bamboo.Email functions
    new_email
    |> to("foo@example.com")
    |> from("me@example.com")
    |> subject("Welcome!!!")
    |> html_body("<strong>Welcome</strong>")
    |> text_body("welcome")
  end
end

# In a controller or some other module
Email.welcome_email |> Mailer.deliver_now

# You can also deliver emails in the background with Mailer.deliver_later
Email.welcome_email |> Mailer.deliver_later

Delivering Emails in the Background

Often times you don’t want to send email right away because it will slow down things like web requests in Phoenix. Bamboo offers deliver_later on your mailers to send emails in the background so that your requests don’t block.

By default delivering later uses Bamboo.TaskSupervisorStrategy. This strategy sends the email right away, but does so in the background without linking to the calling process, so errors in the mailer won’t bring down your app.

If you need something more custom you can can create a strategy with Bamboo.DeliverLaterStrategy. For example, you could create strategies for adding emails to a background processing queue such as exq or toniq.

Composing with Pipes (for default from address, default layouts, etc.)

defmodule MyApp.Emails do
  import Bamboo.Email

  def welcome_email do
    base_email
    |> to("foo@bar.com")
    |> subject("Welcome!!!")
    |> put_header("Reply-To", "someone@example.com")
    |> html_body("<strong>Welcome</strong>")
    |> text_body("Welcome")
  end

  defp base_email do
    # Here you can set a default from, default headers, etc.
    new_email
    |> from("myapp@example.com")
    |> put_html_layout({MyApp.LayoutView, "email.html"})
    |> put_text_layout({MyApp.LayoutView, "text.html"})
  end
end

Handling Recipients

The from, to, cc and bcc addresses can be passed a string, or a 2 item tuple.

Sometimes doing this can be a pain though. What happens if you try to send to a list of users? You’d have to do something like this for every email:

# This stinks. Do you want to do this every time you create a new email?
users = for user <- users do
  {user.name, user.email}
end

new_email(to: users)

To circumvent this, Bamboo has a Bamboo.Formatter protocol. See the Bamboo.Email and Bamboo.Formatter docs for more info and examples.

Using Phoenix Views and Layouts

Phoenix is not required to use Bamboo. However, if you do use Phoenix, you can use Phoenix views and layouts with Bamboo. See Bamboo.Phoenix

Previewing Sent Emails

Bamboo comes with a handy plug for viewing emails sent in development. Now you don’t have to look at the logs to get password resets, confirmation links, etc. Just open up the email preview and click the link.

See Bamboo.EmailPreviewPlug

Here is what it looks like:

Mandrill Specific Functionality (tags, merge vars, etc.)

Mandrill offers extra features on top of regular SMTP email like tagging, merge vars, and scheduling emails to send in the future. See Bamboo.MandrillHelper.

Heroku Configuration

If you are deploying to Heroku, you will need to ensure that your configuration variables are available at compile time. This is done in the build pack config.

config_vars_to_export=(
  DATABASE_URL
  MANDRILL_API_KEY
)

Testing

You can use the Bamboo.TestAdapter along with Bamboo.Test to make testing your emails straightforward.

# Using the mailer from the Getting Started section
defmodule MyApp.Registration do
  use ExUnit.Case
  use Bamboo.Test

  test "welcome email" do
    # Unit testing is easy since the email is just a struct
    user = new_user

    email = Emails.welcome_email(user)

    assert email.to == user
    # The =~ checks that the html_body contains the text on the right
    assert email.html_body =~ "Thanks for joining"
  end

  test "after registering, the user gets a welcome email" do
    # Integration test with the helpers from Bamboo.Test
    user = new_user

    MyApp.Register(user)

    assert_delivered_email MyApp.Email.welcome_email(user)
  end
end

See documentation for Bamboo.Test for more examples, and remember to use Bamboo.TestAdapter.

About thoughtbot

Bamboo is maintained and funded by thoughtbot, inc. The names and logos for thoughtbot are trademarks of thoughtbot, inc.

We love open source software! See our other projects or hire us to design, develop, and grow your product.

Contributing

Before opening a pull request, please open an issue first.

Once we’ve decided how to move forward with a pull request:

$ git clone https://github.com/thoughtbot/bamboo.git
$ cd bamboo
$ mix deps.get
$ mix test

Once you’ve made your additions and mix test passes, go ahead and open a PR!

Thanks!

Thanks to @mtwilliams for an early version of the SendgridAdapter.