Add MySQL Docker Compose profile with isolated services

[Copilot]

Adds MySQL 8.0 as an optional database backend alongside PostgreSQL and SQLite, with dedicated Docker Compose services for development and testing.

Changes

Docker Compose Services

• mysql (profile: mysql) - Development database on port 3306 with health checks and persistent volume
• mysql-test (profile: mysql-test) - Isolated test instance on port 33306 with separate volume
• llm-proxy-mysql (profile: mysql) - Proxy variant on port 8082 using MySQL backend, depends on mysql health

Dockerfile

• Added MYSQL_SUPPORT build argument for conditional MySQL driver compilation
• Enhanced build script to support multiple database tags (postgres, mysql, or both)

Environment Configuration

• Added MySQL credentials (MYSQL_ROOT_PASSWORD, MYSQL_PASSWORD, MYSQL_DATABASE) to .env.example
• Documented MySQL connection string format: user:password@tcp(host:port)/database?parseTime=true
• Updated TLS security documentation to discourage tls=skip-verify in production and recommend tls=true or properly configured custom TLS/CA

Documentation

• Created docs/database/docker-compose-mysql.md with setup, configuration, and troubleshooting guides
• Updated database documentation index with MySQL reference and Aurora MySQL recommendation for AWS ECS deployments

Usage

# Start MySQL stack (database + proxy)
docker compose --profile mysql up -d

# Start test instance only
docker compose --profile mysql-test up -d

# Build with MySQL support
docker build --build-arg MYSQL_SUPPORT=true -t llm-proxy:mysql .

Port Allocation

Service	Port	Purpose
mysql	3306	Development database
mysql-test	33306	Test database (isolated)
llm-proxy-mysql	8082	Proxy with MySQL backend

Follows existing PostgreSQL pattern for consistency. No conflicts with default services (SQLite/PostgreSQL on ports 5432, 8080, 8081).

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[mfittko]

this should also be including MySQL

[Copilot]

Fixed in 42d83f7. Updated the AWS ECS deployment line to include "Aurora PostgreSQL Serverless v2 or Aurora MySQL".

[Copilot]

Pull request overview

This PR adds MySQL 8.0 as an optional database backend for llm-proxy, following the existing PostgreSQL pattern. The implementation uses Docker Compose profiles for opt-in activation, ensuring no conflicts with existing SQLite/PostgreSQL deployments.

Key Changes:

• MySQL Docker services with health checks and isolated test instances
• Conditional MySQL driver compilation via Dockerfile build arguments
• Comprehensive setup and troubleshooting documentation

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
docker-compose.yml	Adds mysql and mysql-test services with profiles, plus llm-proxy-mysql variant on port 8082; includes persistent volumes for both dev and test instances
Dockerfile	Implements MYSQL_SUPPORT build argument with shell logic to combine postgres and mysql build tags conditionally
.env.example	Documents MySQL connection string format and adds MYSQL_ROOT_PASSWORD, MYSQL_PASSWORD, MYSQL_DATABASE variables
docs/database/index.md	Updates database selection guide to include MySQL as an option for multi-instance production
docs/database/docker-compose-mysql.md	New comprehensive guide covering build tags, configuration, integration tests, troubleshooting, and MySQL-specific setup

[Copilot]

This comment recommends using the MySQL DSN parameter tls=skip-verify for production, which disables certificate validation and allows a man-in-the-middle on the network path to impersonate the database server and read or tamper with data. For production, tls=skip-verify should be discouraged and documentation should direct users to use tls=true or a properly configured custom CA (tls=custom) so the client verifies the server certificate.

Suggested change

	# SECURITY: For production, use TLS connection: ?tls=true or ?tls=skip-verify (for self-signed)
	# SECURITY: For production, use TLS with certificate verification: ?tls=true (or a properly configured custom TLS/CA). ?tls=skip-verify disables verification and must not be used in production.

[Copilot]

Fixed in 42d83f7. Updated the security comment to explicitly discourage tls=skip-verify in production and recommend tls=true or properly configured custom TLS/CA instead.

[mfittko]

PR Review: MySQL Docker Compose Profile Implementation

Summary

This PR successfully implements the core MySQL Docker Compose infrastructure as specified in issue #243. The implementation follows the existing PostgreSQL pattern well and includes comprehensive documentation. However, the PR description contains inaccuracies that need addressing, and there are unresolved review comments.

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✅ What's Done Well

Docker Compose Services (All Tasks Complete)

Requirement	Status	Notes
MySQL service with mysql:8.0	✅	Correctly configured on port 3306
mysql-test service	✅	Isolated on port 33306
Health checks	✅	mysqladmin ping with proper timings
Named volumes	✅	mysql_data and mysql_test_data
Profile isolation	✅	mysql and mysql-test profiles
llm-proxy-mysql service	✅	Port 8082, depends on mysql healthy

Dockerfile Enhancement

• Build tag logic properly combines postgres and/or mysql tags
• MYSQL_SUPPORT build argument follows existing pattern
• Shell script logic handles both/either/neither cases correctly

Environment Configuration

• MySQL credentials added to .env.example
• Connection string format documented with DSN examples
• Docker Compose variables added with defaults

Documentation

• Comprehensive 380-line guide covering build tags, setup, testing, troubleshooting
• Database index updated to include MySQL as an option
• Security considerations and performance tuning documented

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❌ Issues Requiring Attention

1. PR Description Inaccuracies (Critical)

The PR description claims changes that do not exist in the diff:

Claimed Change	Actual Status
admin-mysql service on port 8083	❌ Not in code
cmd/proxy/server.go DB driver switch	❌ Not in diff
.github/workflows/docker.yml CI update	❌ Not in diff
Bug fix for Admin UI tokens list	❌ Not in diff

Action Required: Update PR description to accurately reflect the actual changes, or add the missing changes.

2. Unresolved Review Comments

Comment	Location	Status
Security concern: tls=skip-verify documentation	.env.example:30	⚠️ Unresolved
MySQL should be included for AWS ECS	docs/database/index.md:25	⚠️ Unresolved

The security comment about tls=skip-verify being recommended for production is valid - this should be reworded to discourage skip-verify in production.

3. Missing Trailing Newline (Minor)

docker-compose.yml is missing a trailing newline at EOF.

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Acceptance Criteria Verification

Per issue #243:

Criterion	Status
MySQL service starts with docker compose --profile mysql up	✅
Health check passes within start period	✅
Data persists across container restarts	✅
LLM proxy connects to MySQL when configured	✅
mysql-test works independently on port 33306	✅
Port mapping allows local MySQL client connections	✅
No conflicts with existing PostgreSQL/SQLite setups	✅
Named volumes properly declared	✅
Environment variables documented in .env.example	✅

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CI Status

Status checks are pending - should verify tests pass before merge.

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Verdict: Request Changes

The core Docker Compose implementation is solid and follows best practices, but:

1. The PR description is misleading - it claims several changes that aren't in the diff
2. Unresolved review comments need to be addressed before merge
3. CI checks should complete successfully

Once the PR description is corrected and review comments are addressed, this is ready to merge.

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Recommendations for Author

1. Update PR description to match actual changes (remove references to non-existent admin-mysql, server.go, and workflow changes)
2. Address the tls=skip-verify security documentation concern
3. Consider adding Aurora MySQL to the AWS ECS line or respond to the review comment
4. Add trailing newline to docker-compose.yml
5. Verify CI passes

[mfittko]

✅ Approved - MySQL Docker Compose Profile Implementation

All issues from the previous review have been addressed. The implementation is solid and ready to merge.

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Changes Since Last Review

Issue	Resolution
PR description inaccuracies	✅ Fixed - Now accurately reflects actual changes
Security: tls=skip-verify documentation	✅ Fixed in .env.example - Now explicitly discourages skip-verify in production
Aurora MySQL for AWS ECS	✅ Fixed in docs/database/index.md - Added "Aurora MySQL" option
Missing trailing newline	✅ Fixed in docker-compose.yml

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Implementation Quality

Docker Compose Services ✅

• mysql - Development database with health checks on port 3306
• mysql-test - Isolated test instance on port 33306
• llm-proxy-mysql - Proxy variant on port 8082
• Proper profile isolation (mysql, mysql-test)
• Named volumes for data persistence

Dockerfile ✅

• MYSQL_SUPPORT build argument properly implemented
• Build tag logic correctly combines postgres and/or mysql tags

Documentation ✅

• Comprehensive 380-line guide covering all aspects
• Security considerations properly documented
• TLS guidance correct

Environment Configuration ✅

• MySQL credentials and connection string documented
• Security warnings about TLS are appropriate

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Acceptance Criteria (Issue #243)

Criterion	Status
MySQL service starts with docker compose --profile mysql up	✅
Health check passes within start period	✅
Data persists across container restarts	✅
LLM proxy connects to MySQL when configured	✅
mysql-test works independently on port 33306	✅
Port mapping allows local MySQL client connections	✅
No conflicts with existing PostgreSQL/SQLite setups	✅
Named volumes properly declared	✅
Environment variables documented in .env.example	✅

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Note

CI status is pending - please ensure tests pass before merging. Integration tests for MySQL are scheduled separately in #245.

Good work addressing the review feedback! 🎉