Remote MCP servers

Remote MCP Servers

For production deployments, you’ll want to run MCP servers as standalone processes with varlock integrated directly into the server code.

Server Implementation

import 'varlock/auto-load';
import { Server } from '@modelcontextprotocol/sdk/server/index.js';
import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js';
import { ENV } from 'varlock/env';

async function main() {
  const server = new Server(
    {
      name: 'my-mcp-server',
      version: '1.0.0'
    },
    {
      capabilities: {
        tools: {}
      }
    }
  );

  // Register tools with access to secure configuration
  server.setRequestHandler('tools/call', async (request) => {
    const { name, arguments: args } = request.params;

    switch (name) {
      case 'query-database':
        // Use secure database connection from config
        return await queryDatabase(ENV.DATABASE_URL, args);

      case 'call-external-api':
        // Use secure API key from config
        return await callExternalAPI(ENV.EXTERNAL_API_KEY, args);

      default:
        throw new Error(`Unknown tool: ${name}`);
    }
  });

  const transport = new StdioServerTransport(process.stdin, process.stdout);
  await server.connect(transport);
}

async function queryDatabase(databaseUrl: string, args: any) {
  // Implementation using secure database URL
  console.log('Querying database with secure connection');
  return { result: 'database query result' };
}

async function callExternalAPI(apiKey: string, args: any) {
  // Implementation using secure API key
  console.log('Calling external API with secure key');
  return { result: 'api call result' };
}

main().catch(console.error);

Production Deployment

For production, create environment-specific schema files. See the environments guide for detailed information on managing multiple environments with varlock.

# @defaultSensitive=true
# @defaultRequired=true
# @currentEnv=$APP_ENV
# ---

# env flag is used to determine which environment to load
# default is development
# @type=enum(development, staging, test, production)
APP_ENV=development

# Database connection
# @type=url
DATABASE_URL=

# External API credentials
# @type=string(startsWith="sk_")
EXTERNAL_API_KEY=

# Authentication
# @type=string(minLength=32)
AUTH_SECRET=

# Server settings
# @sensitive=false
# @type=number(min=1024, max=65535)
SERVER_PORT=3000

# @sensitive=false
# @type=enum(debug, info, warn, error)
LOG_LEVEL=info

DATABASE_URL=op(op://prodTest/prodVault/prod-database-url)
EXTERNAL_API_KEY=op(op://prodTest/prodVault/prod-external-api-key)
AUTH_SECRET=op(op://prodTest/prodVault/prod-auth-secret)
SERVER_PORT=3000
LOG_LEVEL=warn

Then in the command to start the server, you can use the varlock run command to load the environment variables with the correct currentEnv environment override.

APP_ENV=production varlock run -- node server.js