config.ts•4.73 kB
/**
* Configuration loader for usql-mcp
* Loads config from file and environment variables
*/
import { readFileSync } from "fs";
import { resolve } from "path";
import { UsqlConfig, ConnectionConfig } from "../types/index.js";
import { createLogger } from "../utils/logger.js";
const logger = createLogger("usql-mcp:config");
let cachedConfig: UsqlConfig | null = null;
export function loadConfig(): UsqlConfig {
if (cachedConfig) {
return cachedConfig;
}
const config: UsqlConfig = {
connections: {},
defaults: {
queryTimeout: undefined,
maxResultRows: 10000,
defaultConnection: undefined,
},
};
// Load from config file if present
const configPath = process.env.USQL_CONFIG_PATH || "./config.json";
try {
const fullPath = resolve(configPath);
const content = readFileSync(fullPath, "utf-8");
const fileConfig = JSON.parse(content) as UsqlConfig;
logger.debug("[config] Loaded config from file", { path: configPath });
if (fileConfig.connections) {
config.connections = { ...config.connections, ...fileConfig.connections };
}
if (fileConfig.defaults) {
config.defaults = { ...config.defaults, ...fileConfig.defaults };
}
} catch (error) {
if (process.env.USQL_CONFIG_PATH) {
// Only warn if explicitly configured
logger.warn(
"[config] Could not load config file",
error instanceof Error ? error.message : String(error)
);
} else {
logger.debug("[config] Config file not found (using defaults)");
}
}
// Load from environment variables
// USQL_* env vars are added as connections
for (const [key, value] of Object.entries(process.env)) {
if (
key.startsWith("USQL_") &&
key !== "USQL_CONFIG_PATH" &&
key !== "USQL_QUERY_TIMEOUT_MS" &&
key !== "USQL_DEFAULT_CONNECTION" &&
key !== "USQL_BINARY_PATH" &&
value
) {
const connectionName = key.substring(5).toLowerCase();
config.connections[connectionName] = {
uri: value,
description: `Connection from ${key} environment variable`,
};
logger.debug("[config] Loaded connection from env var", { name: connectionName });
}
}
// Override defaults from environment
if (process.env.USQL_QUERY_TIMEOUT_MS) {
const timeout = parseInt(process.env.USQL_QUERY_TIMEOUT_MS, 10);
if (!isNaN(timeout) && config.defaults) {
config.defaults.queryTimeout = timeout;
logger.debug("[config] Set query timeout from env var", { timeout });
}
}
if (process.env.USQL_DEFAULT_CONNECTION) {
const defaultConnection = process.env.USQL_DEFAULT_CONNECTION.toLowerCase();
if (config.defaults) {
config.defaults.defaultConnection = defaultConnection;
logger.debug("[config] Set default connection from env var", { defaultConnection });
}
}
cachedConfig = config;
logger.debug("[config] Config loaded", {
connections: Object.keys(config.connections).length,
queryTimeout: config.defaults?.queryTimeout,
defaultConnection: config.defaults?.defaultConnection,
});
return config;
}
export function getConnection(nameOrUri: string): ConnectionConfig | null {
const config = loadConfig();
// If it looks like a connection URI, return it directly
if (nameOrUri.includes("://")) {
return { uri: nameOrUri };
}
// Otherwise, look it up by name
const connection = config.connections[nameOrUri.toLowerCase()];
return connection || null;
}
export function resolveConnectionString(nameOrUri: string): string {
const connection = getConnection(nameOrUri);
if (!connection) {
throw new Error(
`Connection not found: ${nameOrUri}. Available connections: ${Object.keys(loadConfig().connections).join(", ")}`
);
}
return connection.uri;
}
export function getQueryTimeout(): number | undefined {
const config = loadConfig();
return config.defaults?.queryTimeout;
}
export function getDefaultConnectionName(): string | undefined {
const config = loadConfig();
return config.defaults?.defaultConnection;
}
export function resolveConnectionStringOrDefault(nameOrUri?: string): string {
if (nameOrUri && typeof nameOrUri === "string" && nameOrUri.trim().length > 0) {
return resolveConnectionString(nameOrUri);
}
const defaultConnection = getDefaultConnectionName();
if (!defaultConnection) {
throw new Error(
"No connection string provided and no default connection configured. Set USQL_DEFAULT_CONNECTION or defaults.defaultConnection."
);
}
return resolveConnectionString(defaultConnection);
}
// Test-only helper to clear cached configuration
export function resetConfigCache(): void {
cachedConfig = null;
}