import winston from 'winston';
function createFormat(): winston.Logform.Format {
const logOutput = (process.env.LOG_OUTPUT || 'file').toLowerCase();
const useConsole = [
'console',
'stdout',
'stderr',
'stderr-all',
'file+console',
'file+stdout',
'file+stderr',
].includes(logOutput);
if (useConsole) {
// Use human-readable format for console output
return winston.format.combine(
winston.format.timestamp({ format: 'YYYY-MM-DD HH:mm:ss.SSS' }),
winston.format.errors({ stack: true }),
winston.format.printf(({ timestamp, level, message, ...meta }) => {
const metaStr = Object.keys(meta).length > 0 ? ` ${JSON.stringify(meta)}` : '';
return `${timestamp} [${level}] ${message}${metaStr}`;
}),
);
} else {
// Use JSON format for file output
return winston.format.combine(
winston.format.timestamp(),
winston.format.errors({ stack: true }),
winston.format.json(),
);
}
}
function createTransports(): winston.transport[] {
const logOutput = (process.env.LOG_OUTPUT || 'file').toLowerCase();
const logFile = process.env.LOG_FILE || 'dynatrace-managed-mcp.log';
switch (logOutput) {
case 'stderr':
// Send only errors and warnings to stderr (standard behavior)
return [
new winston.transports.Console({
stderrLevels: ['error', 'warn'],
}),
];
case 'stderr-all':
// Send all log levels to stderr
return [
new winston.transports.Console({
stderrLevels: ['error', 'warn', 'info', 'http', 'verbose', 'debug', 'silly'],
}),
];
case 'console':
case 'stdout':
// Send all logs to stdout
return [new winston.transports.Console()];
case 'file+console':
case 'file+stdout':
// Log to both file and stdout
return [new winston.transports.File({ filename: logFile }), new winston.transports.Console()];
case 'file+stderr':
// Log to file and send errors/warnings to stderr
return [
new winston.transports.File({ filename: logFile }),
new winston.transports.Console({
stderrLevels: ['error', 'warn'],
}),
];
case 'disabled':
return [];
case 'file':
default:
return [new winston.transports.File({ filename: logFile })];
}
}
export const logger = winston.createLogger({
level: (process.env.LOG_LEVEL || 'info').toLowerCase(),
format: createFormat(),
transports: createTransports(),
});
export async function flushLogger() {
logger.end();
await new Promise((resolve) => logger.once('finish', resolve));
}
