138 lines
3.8 KiB
Markdown
138 lines
3.8 KiB
Markdown
# Database-Driven Mailing List Management
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This mailing list system uses MySQL with **Postfix's native MySQL support** for real-time dynamic list management. Postfix queries the database directly for each email - no scripts or reloads needed.
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## Database Schema
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Three-table design with many-to-many relationships:
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### Tables
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**`lists`** - Mailing list definitions
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- `list_id` (primary key)
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- `list_name` - Display name
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- `list_email` - Full email address (e.g., `community@lists.sasalliance.org`)
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- `description` - Optional description
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- `active` - Boolean flag to enable/disable list
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**`members`** - Member information
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- `member_id` (primary key)
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- `name` - Display name
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- `email` - Email address
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- `active` - Boolean flag to enable/disable member
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**`list_members`** - Subscription junction table
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- `list_id` + `member_id` (composite unique key)
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- `active` - Boolean flag to enable/disable subscription
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- Foreign keys to `lists` and `members`
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## How It Works
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1. **Incoming email** arrives for `community@lists.sasalliance.org`
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2. **Postfix queries MySQL** using the config in `mysql_virtual_alias_maps.cf`
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3. **Database returns** comma-separated list of active member emails
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4. **Postfix expands** the alias and delivers to all members
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5. **Changes take effect immediately** - no restart or reload needed!
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## Managing Lists and Members
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### Via MySQL Client
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Connect to the database:
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```bash
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docker-compose exec mysql mysql -u maillist -p maillist
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```
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### Common Operations
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**View all lists:**
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```sql
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SELECT list_id, list_name, list_email, active FROM lists;
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```
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**View all members:**
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```sql
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SELECT member_id, name, email, active FROM members;
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```
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**View subscriptions for a list:**
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```sql
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SELECT m.name, m.email
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FROM members m
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JOIN list_members lm ON m.member_id = lm.member_id
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JOIN lists l ON lm.list_id = l.list_id
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WHERE l.list_email = 'community@lists.sasalliance.org'
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AND lm.active = TRUE AND m.active = TRUE;
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```
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**Add a new member:**
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```sql
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INSERT INTO members (name, email)
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VALUES ('John Doe', 'john.doe@example.com');
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```
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**Subscribe member to list:**
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```sql
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-- Method 1: Using subqueries (one step)
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INSERT INTO list_members (list_id, member_id)
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VALUES (
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(SELECT list_id FROM lists WHERE list_email = 'community@lists.sasalliance.org'),
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(SELECT member_id FROM members WHERE email = 'john.doe@example.com')
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);
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```
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**Unsubscribe member from list:**
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```sql
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DELETE FROM list_members
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WHERE list_id = (SELECT list_id FROM lists WHERE list_email = 'community@lists.sasalliance.org')
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AND member_id = (SELECT member_id FROM members WHERE email = 'john.doe@example.com');
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```
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**Create a new mailing list:**
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```sql
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INSERT INTO lists (list_name, list_email, description)
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VALUES ('Developers', 'dev@lists.sasalliance.org', 'Developer discussions');
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```
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**Disable a list (keeps data, stops delivery):**
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```sql
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UPDATE lists SET active = FALSE WHERE list_email = 'community@lists.sasalliance.org';
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```
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**Re-enable a list:**
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```sql
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UPDATE lists SET active = TRUE WHERE list_email = 'community@lists.sasalliance.org';
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```
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## Verification
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Test that Postfix can query the database:
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```bash
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docker-compose exec postfix postmap -q "community@lists.sasalliance.org" mysql:/etc/postfix/mysql_virtual_alias_maps.cf
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```
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This should return a comma-separated list of member email addresses.
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## Database Initialization
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The database is automatically initialized from `database/schema.sql` when the MySQL container first starts. Sample data includes:
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- 4 mailing lists (community, board, members, announcements)
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- 2 sample members
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- Sample subscriptions
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### Reset Database
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To completely reset the database (deletes all data!):
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```bash
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docker-compose down -v # Remove volumes
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docker-compose up -d # Reinitialize from schema.sql
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```
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## Performance
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Postfix caches MySQL query results, so the database isn't queried for every single email. The cache TTL is configurable in `mysql_virtual_alias_maps.cf` if needed.
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