/**
* Configuration for MCP Observability Sidecar
*/
export interface MCPSidecarConfig {
/** Upstream MCP server to proxy to */
upstream: {
/** Base URL of upstream MCP server (e.g., http://weather-server:3000) */
url: string;
/** Friendly name for metrics labels */
serverName: string;
/** Timeout for upstream requests in ms */
timeoutMs?: number;
};
/** Listen configuration for incoming MCP clients */
listen: {
port: number;
host?: string;
};
/** OpenTelemetry configuration */
otel: {
serviceName: string;
serviceVersion: string;
environment: string;
exportIntervalMs: number;
endpoint?: string;
};
}
/**
* Load configuration from environment variables
*/
export function loadConfig(): MCPSidecarConfig {
const upstreamUrl = process.env.MCP_UPSTREAM_URL;
if (!upstreamUrl) {
throw new Error('MCP_UPSTREAM_URL environment variable is required');
}
return {
upstream: {
url: upstreamUrl,
serverName: process.env.MCP_UPSTREAM_NAME || 'upstream',
timeoutMs: Number(process.env.MCP_UPSTREAM_TIMEOUT_MS) || 30000,
},
listen: {
port: Number(process.env.PORT) || 4000,
host: process.env.HOST || '0.0.0.0',
},
otel: {
serviceName: process.env.OTEL_SERVICE_NAME || 'mcp-sidecar',
serviceVersion: process.env.SERVICE_VERSION || '0.2.0',
environment: process.env.OTEL_ENV || 'dev',
exportIntervalMs: Number(process.env.OTEL_METRIC_EXPORT_INTERVAL) || 10_000,
endpoint: process.env.OTEL_EXPORTER_OTLP_ENDPOINT,
},
};
}
/**
* Validate configuration
*/
export function validateConfig(config: MCPSidecarConfig): void {
try {
new URL(config.upstream.url);
} catch (err) {
throw new Error(`Invalid MCP_UPSTREAM_URL: ${config.upstream.url}`);
}
if (config.listen.port < 1 || config.listen.port > 65535) {
throw new Error(`Invalid PORT: ${config.listen.port}`);
}
}
