Add Grails 8 email guide sample app.

.github/workflows/grails8.yml

@@ -0,0 +1,50 @@
+name: Grails 8 CI
+
+on:
+  push:
+    branches: [ grails8 ]
+  pull_request:
+    branches: [ grails8 ]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        app: [ initial, complete ]
+    name: ${{ matrix.app }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: '21'
+
+      - name: Set up Gradle
+        uses: gradle/actions/setup-gradle@v4
+
+      - name: Unit tests
+        working-directory: ${{ matrix.app }}
+        run: |
+          chmod +x gradlew
+          ./gradlew test --console=plain --stacktrace
+
+      - name: Integration tests (complete only)
+        if: matrix.app == 'complete'
+        working-directory: complete
+        run: ./gradlew integrationTest --console=plain --stacktrace
+
+      - name: Upload test reports
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-reports-${{ matrix.app }}
+          path: ${{ matrix.app }}/build/reports/tests/
+          if-no-files-found: ignore

README.md

@@ -1,11 +1,103 @@
-# Send Email and Spock Spring
+# grails-email
 
-This repository contains the worked sample app for the [Send Email and Spock Spring](https://grails.apache.org/guides/grails-email/4/guide/index.html) guide on the Apache Grails site.
+Sample app for **Sending Email from a Grails 8 Application (and Testing It)** (Apache Grails `8.0.0-SNAPSHOT`, JDK 21).
 
-## Run the example
+The guide shows how to send mail from a Grails 8 service over SMTP (Grails Mail plugin) and through a provider (SendGrid / AWS SES), how to inject and externalize mail configuration, and how to verify the send interaction using Spock Spring integration tests — without dispatching real email.
 
-`./gradlew bootRun`
+## Layout
 
-## Maintained at apache/grails-static-website
+| Directory | What it is |
+|-----------|------------|
+| `initial/` | Grails 8 REST API starter from [start.grails.org](https://start.grails.org) (`views-json`, `spock`). Work through the guide starting here. |
+| `complete/` | Finished sample — `EmailService` boundary, SMTP / SendGrid / SES implementations, `POST /mail/send`, and a Spock Spring integration spec that mocks the sender. |
 
-The guide narrative is maintained at https://github.com/apache/grails-static-website. Changes to the guide content go there; this repo holds the worked sample app only.
+## Running
+
+```bash
+git clone -b grails8 https://github.com/grails-guides/grails-email.git
+cd grails-email/complete
+./gradlew test integrationTest
+```
+
+To follow the guide step by step, start from `initial/`:
+
+```bash
+cd grails-email/initial
+./gradlew test
+```
+
+Run the finished app locally (SMTP defaults to `localhost:1025` — use [MailHog](https://github.com/mailhog/MailHog) or similar for manual verification):
+
+```bash
+cd grails-email/complete
+./gradlew bootRun
+```
+
+Example endpoint:
+
+```bash
+curl -X POST http://localhost:8080/mail/send \
+  -H 'Content-Type: application/json' \
+  -d '{"recipient":"user@example.com","subject":"Hello","textBody":"Hi there"}'
+```
+
+Switch providers via `application.yml` or environment variables:
+
+| Provider | Set |
+|----------|-----|
+| SMTP (default) | `EMAIL_PROVIDER=smtp` plus `SMTP_HOST`, `SMTP_PORT`, etc. |
+| SendGrid | `EMAIL_PROVIDER=sendgrid`, `SENDGRID_APIKEY`, `SENDGRID_FROM_EMAIL` |
+| AWS SES | `EMAIL_PROVIDER=ses`, `AWS_REGION`, `AWS_SOURCE` (+ standard AWS credentials) |
+
+The integration spec (`MailControllerSpec`) uses a Spock mock for `EmailService` and asserts the message is built and the sender is invoked — no live email is sent in CI.
+
+## Requirements
+
+- **JDK 21** (Temurin recommended; the Gradle build enforces Java 21+)
+- Optional: local SMTP catcher on port **1025** for manual `bootRun` verification
+
+If Gradle reports *"Run this build using a Java 21 or newer JVM"*, switch your shell to JDK 21:
+
+```bash
+sdk install java 21.0.6-tem
+sdk default java 21.0.6-tem
+java -version   # should show 21.x
+```
+
+## The pattern, in one place
+
+```yaml
+# application.yml — pick a provider and externalize secrets
+email:
+  provider: ${EMAIL_PROVIDER:smtp}
+
+grails:
+  mail:
+    host: ${SMTP_HOST:localhost}
+    port: ${SMTP_PORT:1025}
+    default:
+      from: ${SMTP_FROM:no-reply@example.com}
+```
+
+```groovy
+// grails-app/conf/spring/resources.groovy — inject the right implementation
+beans = {
+    def provider = application.config.getProperty('email.provider', String, 'smtp')
+    switch (provider) {
+        case 'sendgrid': emailService(SendGridEmailService); break
+        case 'ses':      emailService(AwsSesEmailService); break
+        case 'smtp':     emailService(SmtpEmailService); break
+        default:         throw new IllegalArgumentException("Unsupported email.provider: ${provider}")
+    }
+}
+```
+
+Grails 8 uses `org.grails.plugins:grails-mail` 5.x from the Grails plugin repository — compatible with Apache Grails 8.
+
+## Guide prose
+
+Published narrative lives on [grails.apache.org/guides](https://grails.apache.org/guides/) in [apache/grails-static-website](https://github.com/apache/grails-static-website) under `guides/grails-email/v8/`.
+
+## CI
+
+GitHub Actions (`.github/workflows/grails8.yml`) runs `./gradlew test` for `initial` and `complete`, and `./gradlew integrationTest` for `complete`, on pushes and PRs to the `grails8` branch.

complete/.gitignore

@@ -10,3 +10,4 @@ out/
 .project
 .settings
 .classpath
+*.log