Breaking changes coming to Bamboo v2.0.0 about bamboo_smtp

[germsvel]

Hi @Aduril and @jarvisjohnson, thanks so much for being quick to look through this. You're right that the main changes in Bamboo 2.0 are to the Bamboo.Mailer API. But in order for that change to work — for bamboo and bamboo_smtp users to be able to handle errors when emails fail to deliver — we also need to change what the adapter's deliver/2 function returns (See the changes to the adapter deliver callback):

-  @callback deliver(%Bamboo.Email{}, %{}) :: any
+  @type error :: Exception.t() | String.t()

+  @callback deliver(%Bamboo.Email{}, %{}) :: {:ok, any} | {:error, error}

That means adapters should no longer raise errors in the adapter code when failing to deliver emails. Instead they should return an {:error, error} tuple, so that Bamboo can handle that. Looking at the smtp_adapter.ex file, my guess is that these are the lines that should now return an error instead of raising one:

bamboo_smtp/lib/bamboo/adapters/smtp_adapter.ex

Lines 98 to 108 in 2c2643e

	defp handle_response({:error, :no_credentials = reason}) do
	raise SMTPError, {reason, "Username and password were not provided for authentication."}
	end
	defp handle_response({:error, reason, detail}) do
	raise SMTPError, {reason, detail}
	end
	defp handle_response({:error, detail}) do
	raise SMTPError, {:not_specified, detail}
	end

If instead of raise SMTPError, bamboo_smtp returns {:error, %SMTPError{}}, then users who call Mailer.deliver_now will get that error tuple back. The users can then handle that in whatever way they see fit (e.g. retrying to send, or keeping a log of what failed, etc.)

For users who call Mailer.deliver_now!, Bamboo will raise the error the adapter passes back, so it'll do an raise %SMTPError{}.

As for the successful case, it seems that bamboo_smtp already returns an {:ok, response}, so that's perfect.

Does all that make sense?

[MatheusBueno782]

Since the pull request #177 that address to this issue was merged I am closing it.

thanks all for the contribution 🙂.

[Aduril]

As far as I see the the major change is towards the API of Bamboo.Mailer (please do not trust my word, check for yourself).

So the change should be an easy version upgrade, right?

[jarvisjohnson]

I think @Aduril is right, bumping the bamboo version seems to be all that is needed.

Have created a PR for this - #177

[jarvisjohnson]

Totally, thanks - I'll make some updates for it to return an :error tuple