db-mcp-server

<div align="center"> <img src="assets/logo.svg" alt="DB MCP Server Logo" width="300" /> # Multi Database MCP Server [](https://opensource.org/licenses/MIT) [](https://goreportcard.com/report/github.com/FreePeak/db-mcp-server) [](https://pkg.go.dev/github.com/FreePeak/db-mcp-server) [](https://github.com/FreePeak/db-mcp-server/graphs/contributors) <h3>A powerful multi-database server implementing the Model Context Protocol (MCP) to provide AI assistants with structured access to databases.</h3> <div class="toc"> <a href="#overview">Overview</a> • <a href="#core-concepts">Core Concepts</a> • <a href="#features">Features</a> • <a href="#supported-databases">Supported Databases</a> • <a href="#deployment-options">Deployment Options</a> • <a href="#configuration">Configuration</a> • <a href="#available-tools">Available Tools</a> • <a href="#examples">Examples</a> • <a href="#troubleshooting">Troubleshooting</a> • <a href="#contributing">Contributing</a> </div> </div> ## Overview The DB MCP Server provides a standardized way for AI models to interact with multiple databases simultaneously. Built on the [FreePeak/cortex](https://github.com/FreePeak/cortex) framework, it enables AI assistants to execute SQL queries, manage transactions, explore schemas, and analyze performance across different database systems through a unified interface. ## Core Concepts ### Multi-Database Support Unlike traditional database connectors, DB MCP Server can connect to and interact with multiple databases concurrently: ```json { "connections": [ { "id": "mysql1", "type": "mysql", "host": "localhost", "port": 3306, "name": "db1", "user": "user1", "password": "password1" }, { "id": "postgres1", "type": "postgres", "host": "localhost", "port": 5432, "name": "db2", "user": "user2", "password": "password2" }, { "id": "oracle1", "type": "oracle", "host": "localhost", "port": 1521, "service_name": "XEPDB1", "user": "user3", "password": "password3" } ] } ``` ### Dynamic Tool Generation For each connected database, the server automatically generates specialized tools: ```go // For a database with ID "mysql1", these tools are generated: query_mysql1 // Execute SQL queries execute_mysql1 // Run data modification statements transaction_mysql1 // Manage transactions schema_mysql1 // Explore database schema performance_mysql1 // Analyze query performance ``` ### Clean Architecture The server follows Clean Architecture principles with these layers: 1. **Domain Layer**: Core business entities and interfaces 2. **Repository Layer**: Data access implementations 3. **Use Case Layer**: Application business logic 4. **Delivery Layer**: External interfaces (MCP tools) ## Features - **Simultaneous Multi-Database Support**: Connect to multiple MySQL, PostgreSQL, SQLite, and Oracle databases concurrently - **Lazy Loading Mode**: Defer connection establishment until first use - perfect for setups with 10+ databases (enable with `--lazy-loading` flag) - **Database-Specific Tool Generation**: Auto-creates specialized tools for each connected database - **Clean Architecture**: Modular design with clear separation of concerns - **OpenAI Agents SDK Compatibility**: Full compatibility for seamless AI assistant integration - **Dynamic Database Tools**: Execute queries, run statements, manage transactions, explore schemas, analyze performance - **Unified Interface**: Consistent interaction patterns across different database types - **Connection Management**: Simple configuration for multiple database connections - **Health Check**: Automatic validation of database connectivity on startup - **Production Guardrails**: Per-database `read_only` enforcement (blocks writes through both `query_*` and `execute_*` tools), `max_rows` result truncation with explicit notices, and per-query timeouts ### Production Guardrails Protect agent sessions against runaway queries and accidental writes: | Setting | Scope | Effect | |---------|-------|--------| | `"read_only": true` | per database | Blocks write statements (`INSERT`, `UPDATE`, `DELETE`, DDL, data-modifying CTEs, stacked writes) through **both** query and execute tools, **and** enforces rejection at the database engine itself on PostgreSQL/TimescaleDB (`default_transaction_read_only=on`) and MySQL (`transaction_read_only=1`); SQLite opens `mode=ro`. Classification strips comments and string literals and defaults to deny for unrecognized statements. | | `"max_rows": 1000` | per database | Truncates result sets at N rows and appends an explicit `[Truncated]` notice so the model knows to refine its query instead of losing context. `0` (default) means unlimited. | | `"masking_rules": [...]` | per database | Masks values of result columns whose **name** matches a rule's regex before they leave the server — applies to every query shape including `SELECT *`. Strategies: `"fixed_string"` (replace with `value`), `"null"`, and `"partial"` (`keep_last` trailing characters visible; shorter values fully masked). First matching rule wins; invalid patterns or unknown strategies abort config load (fail closed); masked-cell counts are reported in the result footer. Renaming a column with an alias bypasses name matching by design. See [docs/design/column-masking-scoping.md](docs/design/column-masking-scoping.md). | | `"query_timeout": 30` | per database | Cancels statements that exceed the timeout in seconds; enforced at the repository layer for every tool (queries, statements, transactions, explain, schema inspection). Unset defaults to 30s; `-1` disables. Env-only deployments can set `QUERY_TIMEOUT_SECONDS` to fill connections without an explicit value (JSON keeps precedence). | | `DB_MCP_AUDIT_LOG=/path/audit.jsonl` | process | Appends one JSONL record per executed statement — timestamp, op (`query`/`execute`/`tx_*`), database, statement (capped at 10k chars), duration, error. Includes rejected attempts against read-only databases. Best-effort writes never fail a query; file is created with `0600`. | > **Defense in depth**: read-only is enforced in three layers — application classifier, engine session defaults, and (recommended) least-privilege database users. Oracle currently relies on the classifier plus user privileges. ## Supported Databases | Database | Status | Features | | ---------- | ------------------------- | ------------------------------------------------------------ | | MySQL | ✅ Full Support | Queries, Transactions, Schema Analysis, Performance Insights | | PostgreSQL | ✅ Full Support (v9.6-17) | Queries, Transactions, Schema Analysis, Performance Insights | | SQLite | ✅ Full Support | File-based & In-memory databases, SQLCipher encryption support | | Oracle | ✅ Full Support (10g-23c) | Queries, Transactions, Schema Analysis, RAC, Cloud Wallet, TNS | | TimescaleDB| ✅ Full Support | Time-Series Queries, Hypertable Discovery (write policies via SQL) | ## Deployment Options The DB MCP Server can be deployed in multiple ways to suit different environments and integration needs: ### Docker Deployment ```bash # Pull the latest image docker pull freepeak/db-mcp-server:latest # Run with mounted config file docker run -p 9092:9092 \ -v $(pwd)/config.json:/app/my-config.json \ -e TRANSPORT_MODE=sse \ -e CONFIG_PATH=/app/my-config.json \ -e DB_MCP_API_KEY=replace-me-with-a-long-random-string \ freepeak/db-mcp-server ``` > **Note**: Mount to `/app/my-config.json` as the container has a default file at `/app/config.json`. #### API-Key Authentication The SSE and streamable-HTTP transports accept an `Authorization: Bearer <key>` header. Set `DB_MCP_API_KEY` (or pass `-api-key`) when launching the Docker container; clients must then send the matching bearer token on every request: ```bash curl -H "Authorization: Bearer replace-me-with-a-long-random-string" \ http://localhost:9092/sse ``` When no API key is configured the transport remains open (single-user / development use). The middleware lives in `internal/delivery/mcp.APIKeyAuth` and is exported so you can compose it with your own reverse proxy if you front the container with nginx, Caddy, or Traefik. ### STDIO Mode (IDE Integration) ```bash # Run the server in STDIO mode ./bin/server -t stdio -c config.json ``` For Cursor IDE integration, add to `.cursor/mcp.json`: ```json { "mcpServers": { "stdio-db-mcp-server": { "command": "/path/to/db-mcp-server/server", "args": ["-t", "stdio", "-c", "/path/to/config.json"] } } } ``` ### SSE Mode (Server-Sent Events) ```bash # Default configuration (localhost:9092) ./bin/server -t sse -c config.json # Custom host and port ./bin/server -t sse -host 0.0.0.0 -port 8080 -c config.json ``` Client connection endpoint: `http://localhost:9092/sse` ### Source Code Installation ```bash # Clone the repository git clone https://github.com/FreePeak/db-mcp-server.git cd db-mcp-server # Build the server make build # Run the server ./bin/server -t sse -c config.json ``` ## Configuration ### Database Configuration File Create a `config.json` file with your database connections: ```json { "connections": [ { "id": "mysql1", "type": "mysql", "host": "mysql1", "port": 3306, "name": "db1", "user": "user1", "password": "password1", "query_timeout": 60, "max_open_conns": 20, "max_idle_conns": 5, "conn_max_lifetime_seconds": 300, "conn_max_idle_time_seconds": 60, "read_only": false, "max_rows": 1000, "masking_rules": [ { "pattern": "(?i)email", "strategy": "fixed_string", "value": "***MASKED***" }, { "pattern": "(?i)(ssn|tax_id)", "strategy": "null" } ] }, { "id": "postgres1", "type": "postgres", "host": "postgres1", "port": 5432, "name": "db1", "user": "user1", "password": "password1" }, { "id": "sqlite_app", "type": "sqlite", "database_path": "./data/app.db", "journal_mode": "WAL", "cache_size": 2000, "read_only": false, "use_modernc_driver": true, "query_timeout": 30, "max_open_conns": 1, "max_idle_conns": 1 }, { "id": "sqlite_encrypted", "type": "sqlite", "database_path": "./data/secure.db", "encryption_key": "your-secret-key-here", "journal_mode": "WAL", "use_modernc_driver": false }, { "id": "sqlite_memory", "type": "sqlite", "database_path": ":memory:", "cache_size": 1000, "use_modernc_driver": true } ] } ``` ### Command-Line Options ```bash # Basic syntax ./bin/server -t <transport> -c <config-file> # SSE transport options ./bin/server -t sse -host <hostname> -port <port> -c <config-file> # Lazy loading mode (recommended for 10+ databases) ./bin/server -t stdio -c <config-file> --lazy-loading # Customize log directory (useful for multi-project setups) ./bin/server -t stdio -c <config-file> -log-dir /tmp/db-mcp-logs # Inline database configuration ./bin/server -t stdio -db-config '{"connections":[...]}' # Environment variable configuration export DB_CONFIG='{"connections":[...]}' ./bin/server -t stdio ``` **Available Flags:** - `-t, -transport`: Transport mode (`stdio` or `sse`) - `-c, -config`: Path to database configuration file - `-p, -port`: Server port for SSE mode (default: 9092) - `-h, -host`: Server host for SSE mode (default: localhost) - `-log-level`: Log level (`debug`, `info`, `warn`, `error`) - `-log-dir`: Directory for log files (default: `./logs` in current directory) - `-db-config`: Inline JSON database configuration ### Environment Variables Values in a `.env` file are loaded first; real environment variables take precedence. A JSON config file (`CONFIG_PATH`/`DB_CONFIG_FILE`) overrides per-database env vars. | Variable | Default | Purpose | |---|---|---| | `CONFIG_PATH` / `DB_CONFIG_FILE` | `config.json` | Path to the multi-database JSON config | | `DB_CONFIG` | — | Inline JSON database configuration (alternative to a file) | | `TRANSPORT_MODE` | `sse` | Transport mode when `-t` is not passed | | `SERVER_PORT` | `9090` | HTTP port for SSE mode | | `LOG_LEVEL` | `info` | Log verbosity (`debug`, `info`, `warn`, `error`) | | `DISABLE_LOGGING` | `false` | `true`/`1` silences logging entirely | | `DB_TYPE`, `DB_HOST`, `DB_PORT`, `DB_USER`, `DB_PASSWORD`, `DB_NAME` | engine defaults | Single-database fallback when no JSON config exists | | `QUERY_TIMEOUT_SECONDS` | unset | Fills connections that don't set their own `query_timeout`; negative disables the cap. JSON configs keep precedence. | ## SQLite Configuration Options When using SQLite databases, you can leverage these additional configuration options: ### SQLite Connection Parameters | Parameter | Type | Default | Description | |-----------|------|---------|-------------| | `database_path` | string | Required | Path to SQLite database file or `:memory:` for in-memory | | `encryption_key` | string | - | Key for SQLCipher encrypted databases | | `read_only` | boolean | false | Open database in read-only mode | | `max_rows` | integer | unlimited | Maximum rows returned per query; larger results are truncated with an explicit notice. Works on all database types | | `cache_size` | integer | 2000 | SQLite cache size in pages | | `journal_mode` | string | "WAL" | Journal mode: DELETE, TRUNCATE, PERSIST, WAL, OFF | | `use_modernc_driver` | boolean | true | Use modernc.org/sqlite (CGO-free) or mattn/go-sqlite3 | ### SQLite Examples #### Basic File Database ```json { "id": "my_sqlite_db", "type": "sqlite", "database_path": "./data/myapp.db", "journal_mode": "WAL", "cache_size": 2000 } ``` #### Encrypted Database (SQLCipher) ```json { "id": "encrypted_db", "type": "sqlite", "database_path": "./data/secure.db", "encryption_key": "your-secret-encryption-key", "use_modernc_driver": false } ``` #### In-Memory Database ```json { "id": "memory_db", "type": "sqlite", "database_path": ":memory:", "cache_size": 1000 } ``` #### Read-Only Database ```json { "id": "reference_data", "type": "sqlite", "database_path": "./data/reference.db", "read_only": true, "journal_mode": "DELETE" } ``` ## Oracle Configuration Options When using Oracle databases, you can leverage these additional configuration options: ### Oracle Connection Parameters | Parameter | Type | Default | Description | |-----------|------|---------|-------------| | `host` | string | Required | Oracle database host | | `port` | integer | 1521 | Oracle listener port | | `service_name` | string | - | Service name (recommended for RAC) | | `sid` | string | - | System identifier (legacy, use service_name instead) | | `user` | string | Required | Database username | | `password` | string | Required | Database password | | `wallet_location` | string | - | Path to Oracle Cloud wallet directory | | `tns_admin` | string | - | Path to directory containing tnsnames.ora | | `tns_entry` | string | - | Named entry from tnsnames.ora | | `edition` | string | - | Edition-Based Redefinition edition name | | `pooling` | boolean | false | Enable driver-level connection pooling | | `standby_sessions` | boolean | false | Allow queries on standby databases | | `nls_lang` | string | AMERICAN_AMERICA.AL32UTF8 | Character set configuration | ### Oracle Examples #### Basic Oracle Connection (Development) ```json { "id": "oracle_dev", "type": "oracle", "host": "localhost", "port": 1521, "service_name": "XEPDB1", "user": "testuser", "password": "testpass", "max_open_conns": 50, "max_idle_conns": 10, "conn_max_lifetime_seconds": 1800 } ``` #### Oracle with SID (Legacy) ```json { "id": "oracle_legacy", "type": "oracle", "host": "oracledb.company.com", "port": 1521, "sid": "ORCL", "user": "app_user", "password": "app_password" } ``` #### Oracle Cloud Autonomous Database (with Wallet) ```json { "id": "oracle_cloud", "type": "oracle", "user": "ADMIN", "password": "your-cloud-password", "wallet_location": "/path/to/wallet_DBNAME", "service_name": "dbname_high" } ``` #### Oracle RAC (Real Application Clusters) ```json { "id": "oracle_rac", "type": "oracle", "host": "scan.company.com", "port": 1521, "service_name": "production", "user": "app_user", "password": "app_password", "max_open_conns": 100, "max_idle_conns": 20 } ``` #### Oracle with TNS Entry ```json { "id": "oracle_tns", "type": "oracle", "tns_admin": "/opt/oracle/network/admin", "tns_entry": "PROD_DB", "user": "app_user", "password": "app_password" } ``` #### Oracle with Edition-Based Redefinition ```json { "id": "oracle_ebr", "type": "oracle", "host": "oracledb.company.com", "port": 1521, "service_name": "production", "user": "app_user", "password": "app_password", "edition": "v2_0" } ``` ### Oracle Connection String Priority When multiple connection methods are configured, the following priority is used: 1. **TNS Entry** (if `tns_entry` and `tns_admin` are configured) 2. **Wallet** (if `wallet_location` is configured) - for Oracle Cloud 3. **Standard** (host:port/service_name) - default method ## Available Tools For each connected database, DB MCP Server automatically generates these specialized tools: ### Query Tools | Tool Name | Description | |-----------|-------------| | `query_<db_id>` | Execute SELECT queries and get results as a tabular dataset | | `execute_<db_id>` | Run data manipulation statements (INSERT, UPDATE, DELETE) | | `transaction_<db_id>` | Begin, commit, and rollback transactions | ### Schema Tools | Tool Name | Description | |-----------|-------------| | `schema_<db_id>` | Get information about tables, columns, indexes, and foreign keys | | `generate_schema_<db_id>` | Generate SQL or code from database schema | ### Performance Tools | Tool Name | Description | |-----------|-------------| | `performance_<db_id>` | Analyze query performance via actions: `stats` / `slow_queries` (in-process tracker), `engine_slow_queries` (pg_stat_statements / MySQL digest tables / Oracle v$sqlarea), `suggest` (static SQL lint), `suggest_indexes` (heuristic CREATE INDEX advice for one statement, equality-first composites, verify with EXPLAIN), `validate_suggestions` (PostgreSQL: installs the same suggestions as cost-free hypothetical indexes via the hypopg extension and reports whether the planner actually picks each one — ground-truth validation instead of manual EXPLAIN), `workload_suggestions` (same analysis across the top-N expensive workload statements, weighted by executions), `index_health` (duplicate/redundant/unused/invalid indexes and table bloat findings from catalogs; usage evidence where engine statistics exist), `db_health` (everything index_health covers plus connection-pressure utilization vs max_connections), `reset` | | `explain_<db_id>` | Show the execution plan for a SQL statement without running it; `analyze: true` executes with timing/buffer stats (PostgreSQL/MySQL). Writes stay blocked on read-only databases | | `describe_<db_id>` | Inspect one table's columns, indexes, and row estimate via engine catalog queries | | `health_<db_id>` | Report connectivity, ping latency, connection-pool state, and engine stats (PostgreSQL buffer-cache hit ratio, MySQL InnoDB buffer efficiency) | ### TimescaleDB Tools For PostgreSQL databases with the `timescaledb` extension installed, these additional specialized tools are registered automatically at startup (registration is config-driven, so it also works under `--lazy-loading`; each handler verifies the extension at call time and returns an actionable error when it is absent): | Tool Name | Description | |-----------|-------------| | `timescaledb_timeseries_query_<db_id>` | Execute optimized time-series queries with time bucketing (`time_bucket`), filtering, and window functions | | `timescaledb_analyze_timeseries_<db_id>` | Analyze time-series patterns (trend, seasonality summary) for one table/column | | `timescaledb_list_hypertables_<db_id>` | List hypertables with their time column and dimension count (read-only) | | `timescaledb_compression_settings_<db_id>` | Show compression configuration for hypertables (read-only) | | `timescaledb_retention_policy_<db_id>` | Show configured retention policies (read-only) | | `timescaledb_list_continuous_aggregates_<db_id>` | List continuous aggregates with bucket interval and refresh policy (read-only) | | `timescaledb_continuous_aggregate_info_<db_id>` | Inspect one continuous aggregate in detail (read-only) | In unified mode the same seven tools appear once as `timescaledb_timeseries_query`, `timescaledb_analyze_timeseries`, `timescaledb_list_hypertables`, `timescaledb_compression_settings`, `timescaledb_retention_policy`, `timescaledb_list_continuous_aggregates`, and `timescaledb_continuous_aggregate_info`, each taking a required `database` parameter. > **Scope note**: read-only discovery above goes through the query pipeline and therefore > stays usable on `read_only` databases; each handler checks for the `timescaledb` > extension first. Write-policy operations (hypertable creation, compression toggles, > add/remove retention or refresh policies) remain unexposed — use plain SQL through > the query/execute tools in the meantime. For detailed documentation, see > [TIMESCALEDB_TOOLS.md](docs/TIMESCALEDB_TOOLS.md). ### Unified Tool Mode If you connect many databases (5+), the per-database tool naming generates a large number of tools (5 × N). Some MCP clients — Claude in particular — apply strict limits on the total number of tools and tool description size that can cause the agent to fail to load the server, ignore tools, or refuse to call them. Issue #18 documents this exact symptom: "the db-mcp-server does not function properly with Claude, even though it works fine with OpenAI". For these clients, launch the server with the `--unified-tools` flag to register six consolidated tools (`query`, `execute`, `transaction`, `performance`, `explain`, `describe`, `schema`, `filter_tables`) instead of per-database tools: ```bash ./bin/server -t stdio -c config.json --unified-tools ``` **Context-window cost (measured, `TestToolTokenBenchmark`, re-verified 2026-08 via `scripts/token-benchmark.sh`):** unified mode costs ~1.25–1.6k tokens **regardless of how many databases are connected**, while per-database mode costs ~800 tokens per database (7 tools each) — 10 connected databases ≈ 8k tokens, an 80% wire-payload saving with unified. With one database only, per-database naming is slightly cheaper; unified wins from two databases onward and scales flat thereafter. Re-measure the real wire payload yourself with `scripts/token-benchmark.sh`; methodology and results in [docs/benchmark-token-efficiency.md](docs/benchmark-token-efficiency.md). ``` In unified mode, each tool accepts a required `database` parameter that names which database the call should target. See the [Configuration](#configuration) section for the full list of available databases. This dramatically reduces the tool count and the cumulative description size, which resolves the Claude compatibility issues. For very large configurations, also enable `--lazy-loading` so that startup doesn't open connections to databases that may never be queried during the session. ## Examples ### Querying Multiple Databases ```sql -- Query the MySQL database query_mysql1("SELECT * FROM users LIMIT 10") -- Query the PostgreSQL database in the same context query_postgres1("SELECT * FROM products WHERE price > 100") -- Query the SQLite database query_sqlite_app("SELECT * FROM local_data WHERE created_at > datetime('now', '-1 day')") -- Query the Oracle database query_oracle_dev("SELECT * FROM employees WHERE hire_date > SYSDATE - 30") ``` ### Managing Transactions The `transaction_<db_id>` tool supports `begin`, `execute`, `commit`, and `rollback` actions. Each `begin` returns a `transactionId`; pass it back to stage statements and to commit or roll back: ```json // 1. Start a transaction { "action": "begin" } // → { "transactionId": "tx_mysql1_1730000000000000000" } // 2. Execute statements within the transaction { "action": "execute", "transactionId": "tx_mysql1_1730000000000000000", "statement": "INSERT INTO orders (customer_id, product_id) VALUES (1, 2)" } // 3a. Commit — persists all staged statements { "action": "commit", "transactionId": "tx_mysql1_1730000000000000000" } // 3b. OR rollback — discards all staged statements { "action": "rollback", "transactionId": "tx_mysql1_1730000000000000000" } ``` Unknown or already-retired transaction IDs return a clear error instead of a silent success, so agents can detect and recover from lost-transaction situations. ### Exploring Database Schema ```sql -- Get all tables in the database schema_mysql1("tables") -- Get columns for a specific table schema_mysql1("columns", "users") -- Get constraints schema_mysql1("constraints", "orders") ``` ### Working with SQLite-Specific Features ```sql -- Create a table in SQLite execute_sqlite_app("CREATE TABLE IF NOT EXISTS local_cache (key TEXT PRIMARY KEY, value TEXT, timestamp DATETIME)") -- Use SQLite-specific date functions query_sqlite_app("SELECT * FROM events WHERE date(created_at) = date('now')") -- Query SQLite master table for schema information query_sqlite_app("SELECT name, sql FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%'") -- Performance optimization with WAL mode execute_sqlite_app("PRAGMA journal_mode = WAL") execute_sqlite_app("PRAGMA synchronous = NORMAL") ``` ### Working with Oracle-Specific Features ```sql -- Query user tables (excludes system schemas) query_oracle_dev("SELECT table_name FROM user_tables ORDER BY table_name") -- Use Oracle-specific date functions query_oracle_dev("SELECT employee_id, hire_date FROM employees WHERE hire_date >= TRUNC(SYSDATE, 'YEAR')") -- Oracle sequence operations execute_oracle_dev("CREATE SEQUENCE emp_seq START WITH 1000 INCREMENT BY 1") query_oracle_dev("SELECT emp_seq.NEXTVAL FROM DUAL") -- Oracle-specific data types query_oracle_dev("SELECT order_id, TO_CHAR(order_date, 'YYYY-MM-DD HH24:MI:SS') FROM orders") -- Get schema metadata from Oracle data dictionary query_oracle_dev("SELECT column_name, data_type, nullable FROM user_tab_columns WHERE table_name = 'EMPLOYEES'") -- Use Oracle analytic functions query_oracle_dev("SELECT employee_id, salary, RANK() OVER (ORDER BY salary DESC) as salary_rank FROM employees") ``` ## Troubleshooting ### Common Issues - **Connection Failures**: Verify network connectivity and database credentials - **Permission Errors**: Ensure the database user has appropriate permissions - **Timeout Issues**: Check the `query_timeout` setting in your configuration ### Logs Enable verbose logging for troubleshooting: ```bash ./bin/server -t sse -c config.json -v ``` ## Testing ### Running Tests The project includes comprehensive unit and integration tests for all supported databases. #### Unit Tests Run unit tests (no database required): ```bash make test # or go test -short ./... ``` #### Integration Tests Integration tests require running database instances. We provide Docker Compose configurations for easy setup. **Test All Databases:** ```bash # Start test databases docker-compose -f docker-compose.test.yml up -d # Run all integration tests go test ./... -v # Stop test databases docker-compose -f docker-compose.test.yml down -v ``` **Test Oracle Database:** ```bash # Start Oracle test environment ./oracle-test.sh start # Run Oracle tests ./oracle-test.sh test # or manually ORACLE_TEST_HOST=localhost go test -v ./pkg/db -run TestOracle ORACLE_TEST_HOST=localhost go test -v ./pkg/dbtools -run TestOracle # Stop Oracle test environment ./oracle-test.sh stop # Full cleanup (removes volumes) ./oracle-test.sh cleanup ``` **Test TimescaleDB:** ```bash # Start TimescaleDB test environment ./timescaledb-test.sh start # Run TimescaleDB tests TIMESCALEDB_TEST_HOST=localhost go test -v ./pkg/db/timescale ./internal/delivery/mcp # Stop TimescaleDB test environment ./timescaledb-test.sh stop ``` #### Regression Tests Run comprehensive regression tests across all database types: ```bash # Ensure all test databases are running docker-compose -f docker-compose.test.yml up -d ./oracle-test.sh start # Run regression tests MYSQL_TEST_HOST=localhost \ POSTGRES_TEST_HOST=localhost \ ORACLE_TEST_HOST=localhost \ go test -v ./pkg/db -run TestRegression # Run connection pooling tests go test -v ./pkg/db -run TestConnectionPooling ``` ### Continuous Integration All tests run automatically on every pull request via GitHub Actions. The CI pipeline includes: - **Unit Tests**: Fast tests that don't require database connections - **Integration Tests**: Tests against MySQL, PostgreSQL, SQLite, and Oracle databases - **Regression Tests**: Comprehensive tests ensuring backward compatibility - **Linting**: Code quality checks with golangci-lint ## Contributing We welcome contributions to the DB MCP Server project! To contribute: 1. Fork the repository 2. Create a feature branch (`git checkout -b feature/amazing-feature`) 3. Commit your changes (`git commit -m 'feat: add amazing feature'`) 4. Push to the branch (`git push origin feature/amazing-feature`) 5. Open a Pull Request Please see our [CONTRIBUTING.md](docs/CONTRIBUTING.md) file for detailed guidelines. ### Testing Your Changes Before submitting a pull request, please ensure: 1. All unit tests pass: `go test -short ./...` 2. Integration tests pass for affected databases 3. Code follows the project's style guidelines: `golangci-lint run ./...` 4. New features include appropriate test coverage ## License This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.