Email templating engine by stefanotroncaro · Pull Request #34 · Light-it-labs/fastapi-template

stefanotroncaro · 2025-11-05T22:18:02Z

Create templates submodule

Features

jinja2 based rendering
mjml rendering via mrml library
inheritable BaseTemplate and BaseEmailTemplate pydantic schemas to relate template files and required arguments
flexible post rendering pipeline configurable on 3 levels: template definition, render method call, and service instance
component based template definition example, defining a theme to follow a design system for template consistency
module usage examples

Proof of testing

Sample email

Test suite

Build/bump python to 3.13.8

DanTcheche · 2025-12-29T13:11:33Z

-            error_message=f"Sending new user email to user {user.id} failed",
+        from app.users.schemas.templates import NewUserTemplate
+
+        template = NewUserTemplate(name=user.email)


I'm not sure about the template not being inyectable here. Is there a specific reason?
I'm thinking about maybe A/B testing where you want to send 2 different new user emails to users depending on X factor.

I totally agree with you.

I want to add that functionality on a later refactor, to clean up the email service so that it is closed for modification (which it currently is not, as it basically requires a new method for each email type).

I didn't do it here because I didn't want to scope creep this PR. Would you be ok with working on that on a different PR?

Copilot

Pull request overview

This PR introduces a comprehensive email templating system based on Jinja2 and MJML, replacing the previous simple HTML template approach. The new system provides a flexible, component-based architecture for creating and rendering email templates with consistent styling through a design system.

Changes:

Implemented a new templates module with base classes, services, and utilities for template rendering
Created a component-based email template system using Jinja2 and MJML with reusable atoms (text, image, heading) and molecules (section, column)
Migrated email service from file-based HTML templates to the new templating system with proper error handling

Reviewed changes

Copilot reviewed 30 out of 31 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
pyproject.toml	Added jinja2 and mjml-python dependencies
.python-version	Updated Python version from 3.12.9 to 3.13.8
app/templates/services/templates_service.py	Core service for rendering templates with configurable processing pipelines
app/templates/schemas/base_template.py	Base schema for templates with path and pipeline configuration
app/templates/schemas/base_email_template.py	Email-specific template schema with MJML rendering
app/emails/services/emails_service.py	Refactored to use new template service instead of file-based templates
assets/templates/*.j2	New Jinja2 template files for layouts, components, and email content
app/users/schemas/templates.py	Example template definition for new user emails
app/core/config.py	Added "test" environment to RUN_ENV literal

Copilot · 2026-01-26T14:03:28Z

+{% from "constants/theme.j2" import theme %}
+{% from "utils/render_attributes.j2" import render_attributes %}
+
+{% macro text(variant='h1', styles={}) %}


The macro is named 'text' but the file is 'heading.j2' and it renders heading variants (h1, h2, h3). The macro name should be 'heading' to match the file name and its purpose.

Suggested change

{% macro text(variant='h1', styles={}) %}

{% macro heading(variant='h1', styles={}) %}

Copilot · 2026-01-26T14:03:29Z

+
+            Example:
+            ```
+            class {cls_name}(BaseTemplate, path="path/to/template.mj"):


Corrected file extension from 'mj' to 'j2' in the example.

Suggested change

class {cls_name}(BaseTemplate, path="path/to/template.mj"):

class {cls_name}(BaseTemplate, path="path/to/template.j2"):

Copilot · 2026-01-26T14:03:29Z

-            max_retries=settings.SEND_WELCOME_EMAIL_MAX_RETRIES,
-            backoff_in_seconds=settings.SEND_WELCOME_EMAIL_RETRY_BACKOFF_VALUE,
-            error_message=f"Sending new user email to user {user.id} failed",
+        from app.users.schemas.templates import NewUserTemplate


The import statement is placed inside the method rather than at the module level. Move this import to the top of the file with other imports to follow Python conventions and improve code clarity.

Copilot · 2026-01-26T14:03:30Z

-            user.email,
-            Paths.NEW_USER.value,
-            "Welcome",
+        from app.users.schemas.templates import NewUserTemplate


The import statement is placed inside the method rather than at the module level. Move this import to the top of the file with other imports to follow Python conventions and improve code clarity.

Copilot · 2026-01-26T14:03:30Z

@@ -0,0 +1,2 @@
+from .invalid_template_path_exception import InvalidTemplatePathException
+from .template_missing_path_exception import TemplateMissingPathException


Missing all definition. Add all to explicitly declare the public API, consistent with other modules in the codebase.

Suggested change

from .template_missing_path_exception import TemplateMissingPathException

from .template_missing_path_exception import TemplateMissingPathException

__all__ = [

"InvalidTemplatePathException",

"TemplateMissingPathException",

]

stefanotroncaro and others added 8 commits October 15, 2025 12:19

build: bump python to 3.13.8

3f09790

build: bump dependencies

0e309d5

Merge pull request #31 from Light-it-labs/build/bump-python-to-3.13.8

fc5371d

Build/bump python to 3.13.8

Merge branch 'main' into feat/email-templates

164fb22

feat: email templates service

abd2932

feat: refactor email service to use template service

677de7f

fix: test environment

10b02ae

fix: wrong kwargs for other email

270315a

stefanotroncaro marked this pull request as ready for review November 5, 2025 22:28

stefanotroncaro requested review from DanTcheche and jsarrolt November 5, 2025 22:28

dwaldeck-light-it reviewed Nov 5, 2025

View reviewed changes

Comment thread app/emails/templates/_base.j2 Outdated

feat: component based template

4201a54

stefanotroncaro marked this pull request as draft November 6, 2025 15:39

stefanotroncaro added 7 commits November 21, 2025 21:19

refactor: templates into a module

dee7352

feat: mjml rendering

a4e7079

refactor: templates out of emails/notifications module

1a8c486

refactor: template path declaration

939e560

feat: extract template layout

49919f3

feat: component based template

3502681

refactor: remove comment

73c6c7f

stefanotroncaro marked this pull request as ready for review November 28, 2025 20:29

stefanotroncaro requested a review from dwaldeck-light-it November 28, 2025 20:35

DanTcheche requested changes Dec 29, 2025

View reviewed changes

DanTcheche requested a review from Copilot January 26, 2026 14:02

Copilot AI reviewed Jan 26, 2026

View reviewed changes

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Email templating engine#34

Email templating engine#34
stefanotroncaro wants to merge 16 commits into
feat/email-service-asyncfrom
feat/email-templates

stefanotroncaro commented Nov 5, 2025 •

edited

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	{% macro text(variant='h1', styles={}) %}
	{% macro heading(variant='h1', styles={}) %}

	class {cls_name}(BaseTemplate, path="path/to/template.mj"):
	class {cls_name}(BaseTemplate, path="path/to/template.j2"):

		@@ -0,0 +1,2 @@
		from .invalid_template_path_exception import InvalidTemplatePathException
		from .template_missing_path_exception import TemplateMissingPathException

-from .template_missing_path_exception import TemplateMissingPathException
+from .template_missing_path_exception import TemplateMissingPathException
+__all__ = [
+    "InvalidTemplatePathException",
+    "TemplateMissingPathException",
+]

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stefanotroncaro commented Nov 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Create templates submodule

Features

Proof of testing

Sample email

Test suite

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stefanotroncaro commented Nov 5, 2025 •

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