Initial commit

src/logger.js

@@ -0,0 +1,143 @@
+const LEVELS = Object.freeze({
+  debug: 10,
+  info: 20,
+  warn: 30,
+  error: 40,
+  silent: 100,
+})
+
+const REDACTED = '[redacted]'
+const SECRET_KEY_RE = /(^|_)(api[-_]?key|authorization|password|secret|token|credential)($|_)/i
+const MAX_STRING_LENGTH = 2000
+
+function normalizeLevel(value, fallback = 'info') {
+  const level = String(value ?? '').trim().toLowerCase()
+  return Object.hasOwn(LEVELS, level) ? level : fallback
+}
+
+function normalizeFormat(value) {
+  return String(value ?? '').trim().toLowerCase() === 'json' ? 'json' : 'text'
+}
+
+function sanitizeValue(value) {
+  if (value instanceof Error) {
+    return {
+      name: value.name,
+      message: value.message,
+      code: value.code,
+      status: value.status,
+      stack: value.stack,
+    }
+  }
+  if (typeof value === 'string') {
+    return value.length > MAX_STRING_LENGTH
+      ? `${value.slice(0, MAX_STRING_LENGTH)}… (${value.length - MAX_STRING_LENGTH} more characters)`
+      : value
+  }
+  if (typeof value === 'bigint') return value.toString()
+  if (Array.isArray(value)) return value.map(sanitizeValue)
+  if (value && typeof value === 'object') {
+    const result = {}
+    for (const [key, entry] of Object.entries(value)) {
+      result[key] = SECRET_KEY_RE.test(key) ? REDACTED : sanitizeValue(entry)
+    }
+    return result
+  }
+  return value
+}
+
+function formatScalar(value) {
+  if (value === null) return 'null'
+  if (typeof value === 'string') {
+    return /^[A-Za-z0-9_./:@[\]-]+$/.test(value) ? value : JSON.stringify(value)
+  }
+  if (typeof value === 'object') return JSON.stringify(value)
+  return String(value)
+}
+
+function formatText(timestamp, level, message, fields) {
+  const parts = [timestamp, level.toUpperCase().padEnd(5), message]
+  for (const [key, value] of Object.entries(fields)) {
+    if (value === undefined) continue
+    parts.push(`${key}=${formatScalar(value)}`)
+  }
+  return `${parts.join(' ')}\n`
+}
+
+function formatJson(timestamp, level, message, fields) {
+  return `${JSON.stringify({ timestamp, level, message, ...fields })}\n`
+}
+
+/**
+ * Create a small dependency-free logger.
+ *
+ * LOG_LEVEL: debug | info | warn | error | silent (default: info)
+ * LOG_FORMAT: text | json (default: text)
+ *
+ * All output goes to stderr so the CLI can keep stdout for the PDF path.
+ */
+export function createLogger({
+  level = process.env.LOG_LEVEL,
+  format = process.env.LOG_FORMAT,
+  stream = process.stderr,
+  bindings = {},
+} = {}) {
+  const configuredLevel = normalizeLevel(level)
+  const configuredFormat = normalizeFormat(format)
+  const threshold = LEVELS[configuredLevel]
+  const parentBindings = { ...bindings }
+
+  function write(logLevel, message, fields = {}) {
+    if (LEVELS[logLevel] < threshold) return
+
+    const timestamp = new Date().toISOString()
+    const merged = { ...parentBindings, ...fields }
+    const sanitized = {}
+    for (const [key, value] of Object.entries(merged)) {
+      if (value === undefined) continue
+      sanitized[key] = SECRET_KEY_RE.test(key) ? REDACTED : sanitizeValue(value)
+    }
+
+    const line =
+      configuredFormat === 'json'
+        ? formatJson(timestamp, logLevel, String(message), sanitized)
+        : formatText(timestamp, logLevel, String(message), sanitized)
+
+    try {
+      stream.write(line)
+    } catch {
+      // Logging must never break an export.
+    }
+  }
+
+  return {
+    level: configuredLevel,
+    format: configuredFormat,
+    bindings: parentBindings,
+    isLevelEnabled(logLevel) {
+      return LEVELS[logLevel] >= threshold
+    },
+    child(extraBindings = {}) {
+      return createLogger({
+        level: configuredLevel,
+        format: configuredFormat,
+        stream,
+        bindings: { ...parentBindings, ...extraBindings },
+      })
+    },
+    debug(message, fields) {
+      write('debug', message, fields)
+    },
+    info(message, fields) {
+      write('info', message, fields)
+    },
+    warn(message, fields) {
+      write('warn', message, fields)
+    },
+    error(message, fields) {
+      write('error', message, fields)
+    },
+  }
+}
+
+export const logger = createLogger({ bindings: { app: 'wiki-print' } })