PAS-452 | Design generic fallback for e-mail providers & drop PostMark

[jonashendrickx]

Ticket

• Closes PAS-452

Description

This pull request removes support for Postmark.

Any e-mail provider, including Postmark, can still continue to be configured using SMTP. Read more here.

Shape

Features:

• Allow configuration of an ordered list of mail providers.
• Can combine multiple mail providers of the same type, i.e. AWS. For example, can be used if one region is down, and fall back to using a different region. This is purely an example, as not every mail provider could support this out of the box.
• When no mail provider is configured, use the FileMailProvider
• Allow updating the provider configurations without having to restart the application.

In the example below, we're able to attempt to send e-mails first using AWS SES using region us-west-2, if this fails, we fall back to AWS SES using region us-east-2. If that again fails, we attempt to send e-mails using SendGrid. Please note the example is purely hypothetical and ignores any vendor specific features such as the availability zones with redundant connections with AWS SES to guarantee minimum down-time.

If all configured attempts fail, an error will be thrown by the back-end.

  "Mail": {
    "From": "johndoe@example.com",
    "Providers": [
      {
        "Name": "aws",
        "AccessKey": "aws_access_key_id",
        "SecretKey": "aws_secret_key",
        "Region": "us-west-2"
      },
      {
        "Name": "aws",
        "AccessKey": "aws_access_key_id",
        "SecretKey": "aws_secret_key",
        "Region": "us-east-1"
      },
      {
        "Name": "sendgrid",
        "ApiKey": "sendgrid_api_key"
      }
    ]
  },

Screenshots

Checklist

I did the following to ensure that my changes were tested thoroughly:

• __

I did the following to ensure that my changes do not introduce security vulnerabilities:

• __

[codecov]

Codecov Report

Attention: Patch coverage is 34.11215% with 141 lines in your changes missing coverage. Please review.

Project coverage is 35.13%. Comparing base (4861cbe) to head (3582e58).

Files	Patch %	Lines
src/Common/Services/Mail/Aws/AwsMailProvider.cs	0.00%	50 Missing ⚠️
...mon/Services/Mail/SendGrid/SendGridMailProvider.cs	0.00%	18 Missing ⚠️
src/Common/Services/Mail/MailProviderFactory.cs	0.00%	16 Missing ⚠️
src/Common/Services/Mail/MailBootstrap.cs	58.33%	14 Missing and 1 partial ⚠️
src/Common/Services/Mail/MailMessage.cs	50.00%	10 Missing ⚠️
src/Common/Services/Mail/Smtp/SmtpMailProvider.cs	0.00%	10 Missing ⚠️
...mmon/Services/Mail/Smtp/SmtpMailProviderOptions.cs	0.00%	9 Missing ⚠️
...sole/Components/Pages/Organization/Verify.razor.cs	57.14%	4 Missing and 2 partials ⚠️
src/Common/HealthChecks/MailKitHealthCheck.cs	0.00%	3 Missing ⚠️
src/Common/Services/Mail/File/FileMailProvider.cs	0.00%	3 Missing ⚠️
... and 1 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #636      +/-   ##
==========================================
- Coverage   35.15%   35.13%   -0.02%     
==========================================
  Files         568      574       +6     
  Lines       31012    31144     +132     
  Branches      929      929              
==========================================
+ Hits        10903    10944      +41     
- Misses      19961    20055      +94     
+ Partials      148      145       -3     

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[abergs]

@jonashendrickx we're not merging this until more work is done in PAS-452, right?

[Tyrrrz]

I think we should have a no-op mail provider in the default case. This may be useful in tests, where you don't care about emails at all and the app in the container may not have the permissions to have files.

[jonashendrickx]

We can add support for it later in the integration testing project