Modular Monolith SAAS Starter

Use cases

• Base solution for a medium - large saas
• github style user / organsation model but with projects instead of repo's
• modular in nature to allow additional feature domains

Tech Stack

• modular monolith
• choose boring technologies
  • postgres
  • ef/dapper
  • razor pages
  • htmx
  • transactional outbox

Modules

Users Module

• ✌️ Users can register
• ✌️ Users can login
• ✌️ Users can reset password
• ✌️ Users can update name
• ✌️ Users can update password
• ✌️ Users can create ApiKey
• ✌️ Users can list ApiKeys
• ✌️ Users can revoke ApiKeys
• ✌️ Users can authenticate with ApiKey

Tenants Module

• ✌️ Users can create organisations
• ✌️ Users can be organisation administrators
• ✌️ Users can operate within an organisation's context
• ✌️ Users can add and remove members
• ✌️ Users can promote and demote members
• ✌️ Users can delete organisations
• ✌️ Users can create invitations
• ❌ Users can accept invitations and become members
• ❌ Users can reject invitations
• ✌️ Users can create projects
• ✌️ Users can operate within an projects's context
• ❓ Should projects be moved to their own modules?
• ❓ Should invitiations be moved out to its own module too?

Translations Module

• ✌️ Users can create terms
• ✌️ Users can update terms
• ✌️ Users can delete terms
• ✌️ Users can add languages
• ✌️ Users can add translations of a term to a language
• ✌️ Users can update translations of a term to a language
• ✌️ Users can import terms
• ✌️ Users can import translations
• ✌️ Users can generate statistics on terms/translations
• ✌️ Users can export to RESX files
• ✌️ Users can export to CSV files
• ✌️ Route to this via a 'Project scoped module' route
• ❓ Rename to 'Localisation' module

System Considerations

• ✌️ Modules are well isolated, communicate via integration events
• ✌️ Modules contain complete functionality, razor pages / api endpoints included.
• ✌️ Use transactional outbox for publishing events
• ✌️ Publish integration events via transactional outbox
• ✌️ Publish queued commands via transactional outbox
• ✌️ In memory publishing of events between each module's outbox and another's inbox
• ❌ AWS SQS for outbox/inbox (https://github.com/awslabs/aws-dotnet-messaging or similar)
• ✌️ Distinct container instance and composition root foreach module
• ❌ Security at the postgres connection level via connection context being set

Conventions

As the razor pages co-habitate in the web host a convention is needed to ensure the routes are globally unique. :question: Perhaps modules could defined user, org and project scoped functionality?

• User Scoped modules

  • 💻 /users/{user}/{module}/{path}
  • 💻 /users/peter/tasks/list

• Org Scoped modules

  • 💻 /orgs/{org}/{module}/{path}
  • 💻 /ogs/microsoft/invitations/list

• Project Scoped modules

  • 💻 /orgs/{org}/projects/{project}/{module}/{path}
  • 💻 /ogs/microsoft/projects/landing-page/localisation/terms/list
  • 💻 /ogs/microsoft/projects/landing-page/localisation/translations/en-au/list

Acceptance Tests

• ✌️ Added PageIds to identify the current page
• ✌️ Organisation Selector Tests
• ✌️ Project Selector Tests
• ❌ User Menu Tests
• ✌️ Basic user flow Tests
• Logs impersonation links for easier manual retesting of scenarios

Other

Context

• Endpoint
  • Endpoint provides a context accessor for modules to retreive the context of a command or query
  • Context is retrieved via route parameters and authentication details

dotnet ef dbcontext scaffold "Username=admin;Password=password;Database=db;Host=localhost;Port=5432;Search Path=translate;Include Error Detail=true;Log Parameters=true" \
  Npgsql.EntityFrameworkCore.PostgreSQL \
  -o Infrastructure/temp \
  -c "Db"

todo:

• remove all schema prefixes from application layer
• remove all ef queries from application layer
• look into SqlMapper.AddTypeHandler(LanguageIdTypeHandler.Default);

Saas Ideas

• Monitoring
  • Check HTTP Endpoint health
  • Check IP Address health
  • Check DNS resolution
• Image resizing
  • Thumbnail generation
• PDF generation
  • HTML to PDF
  • URL to PDF
• Feature switches
  • Manual
  • User based
  • Time based
  • Percentage based
  • Random
• Content Management
  • Data Types
  • Tags
  • Search / List / Filter
• Organisation Invitations
• Project Invitations
• Notifications (Email, SMS, Push)
• Analytics
• Metrics
  • Counters
  • Gauges
  • Timers
  • Embeddable via URL / Iframe
• Security
  • User permissions
  • User role
  • User groups