import { createWriteStream, mkdirSync } from "node:fs";import type { WriteStream } from "node:fs";import { dirname } from "node:path"; export type LogLevel = "debug" | "info" | "warn" | "error"; export interface LoggerOptions { filePath?: string; /** Called after formatting a log line (best-effort). Useful for pushing logs to SSE channels. */ onLine?: (line: string, meta: { level: LogLevel }) => void | Promise<void>;} export interface Logger { debug: (message: string, details?: Record<string, unknown>) => void; info: (message: string, details?: Record<string, unknown>) => void; warn: (message: string, details?: Record<string, unknown>) => void; error: (message: string, details?: Record<string, unknown>) => void;} export const createLogger = (level: LogLevel, options: LoggerOptions = {}): Logger => { const stream = ((): WriteStream | null => { if (!options.filePath) return null; try { mkdirSync(dirname(options.filePath), { recursive: true }); return createWriteStream(options.filePath, { flags: "a" }); } catch { return null; } })(); const priority: Record<LogLevel, number> = { debug: 10, info: 20, warn: 30, error: 40, }; const shouldLog = (target: LogLevel): boolean => priority[target] >= priority[level]; const format = (message: string, details?: Record<string, unknown>): string => { if (!details || Object.keys(details).length === 0) { return message; } return `${message} ${JSON.stringify(details)}`; }; const toFileLine = ( target: LogLevel, message: string, details?: Record<string, unknown>, ): string => { const ts = new Date().toISOString(); const base = format(message, details); return `${ts} ${target.toUpperCase()} ${base}\n`; }; const tryWrite = (target: LogLevel, message: string, details?: Record<string, unknown>): void => { const line = toFileLine(target, message, details); if (stream) { try { stream.write(line); } catch { // best-effort } } if (options.onLine) { try { void options.onLine(line.trimEnd(), { level: target }); } catch { // best-effort } } }; return { debug: (message, details): void => { if (shouldLog("debug")) { console.debug(format(message, details)); tryWrite("debug", message, details); } }, info: (message, details): void => { if (shouldLog("info")) { console.info(format(message, details)); tryWrite("info", message, details); } }, warn: (message, details): void => { if (shouldLog("warn")) { console.warn(format(message, details)); tryWrite("warn", message, details); } }, error: (message, details): void => { if (shouldLog("error")) { console.error(format(message, details)); tryWrite("error", message, details); } }, };}; export const resolveLogLevel = (fallback: LogLevel): LogLevel => { const raw = process.env["LOCAL_STUDIO_LOG_LEVEL"]?.toLowerCase(); if (raw === "debug" || raw === "info" || raw === "warn" || raw === "error") { return raw; } return fallback;};
import { createWriteStream, mkdirSync } from "node:fs";
import type { WriteStream } from "node:fs";
import { dirname } from "node:path";
export type LogLevel = "debug" | "info" | "warn" | "error";
export interface LoggerOptions {
filePath?: string;
/** Called after formatting a log line (best-effort). Useful for pushing logs to SSE channels. */
onLine?: (line: string, meta: { level: LogLevel }) => void | Promise<void>;
}
export interface Logger {
debug: (message: string, details?: Record<string, unknown>) => void;
info: (message: string, details?: Record<string, unknown>) => void;
warn: (message: string, details?: Record<string, unknown>) => void;
error: (message: string, details?: Record<string, unknown>) => void;
}
export const createLogger = (level: LogLevel, options: LoggerOptions = {}): Logger => {
const stream = ((): WriteStream | null => {
if (!options.filePath) return null;
try {
mkdirSync(dirname(options.filePath), { recursive: true });
return createWriteStream(options.filePath, { flags: "a" });
} catch {
return null;
}
})();
const priority: Record<LogLevel, number> = {
debug: 10,
info: 20,
warn: 30,
error: 40,
};
const shouldLog = (target: LogLevel): boolean => priority[target] >= priority[level];
const format = (message: string, details?: Record<string, unknown>): string => {
if (!details || Object.keys(details).length === 0) {
return message;
}
return `${message} ${JSON.stringify(details)}`;
};
const toFileLine = (
target: LogLevel,
message: string,
details?: Record<string, unknown>,
): string => {
const ts = new Date().toISOString();
const base = format(message, details);
return `${ts} ${target.toUpperCase()} ${base}\n`;
};
const tryWrite = (target: LogLevel, message: string, details?: Record<string, unknown>): void => {
const line = toFileLine(target, message, details);
if (stream) {
try {
stream.write(line);
} catch {
// best-effort
}
}
if (options.onLine) {
try {
void options.onLine(line.trimEnd(), { level: target });
} catch {
// best-effort
}
}
};
return {
debug: (message, details): void => {
if (shouldLog("debug")) {
console.debug(format(message, details));
tryWrite("debug", message, details);
}
},
info: (message, details): void => {
if (shouldLog("info")) {
console.info(format(message, details));
tryWrite("info", message, details);
}
},
warn: (message, details): void => {
if (shouldLog("warn")) {
console.warn(format(message, details));
tryWrite("warn", message, details);
}
},
error: (message, details): void => {
if (shouldLog("error")) {
console.error(format(message, details));
tryWrite("error", message, details);
}
},
};
};
export const resolveLogLevel = (fallback: LogLevel): LogLevel => {
const raw = process.env["LOCAL_STUDIO_LOG_LEVEL"]?.toLowerCase();
if (raw === "debug" || raw === "info" || raw === "warn" || raw === "error") {
return raw;
}
return fallback;
};