53 lines
1.9 KiB
JavaScript
53 lines
1.9 KiB
JavaScript
// Generic numbered-backup log rotation. Used by the upload log + can be
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// reused by other long-lived log files (debug log, account-rotation log).
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//
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// Behaviour:
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// - File missing → no-op, returns false.
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// - File ≤ maxBytes → no-op, returns false.
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// - File > maxBytes → drop oldest .N backup, shift .K → .K+1, rename live
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// file to .1, return true. Caller (or the next append) creates a fresh
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// primary on demand.
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//
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// Errors are reported via `log` (e.g. debugLog) but never thrown — rotation
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// is best-effort; the caller's append happens anyway.
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const fs = require('fs');
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const path = require('path');
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function maybeRotateLogFile(filePath, maxBytes, maxBackups = 3, log = () => {}) {
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if (!filePath || !Number.isFinite(maxBytes) || maxBytes <= 0) return false;
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let size = 0;
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try {
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const st = fs.statSync(filePath);
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size = st.size;
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} catch (err) {
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// ENOENT is normal — nothing to rotate yet.
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if (err && err.code !== 'ENOENT') {
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log(`logRotation: stat ${filePath} failed: ${err.message}`);
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}
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return false;
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}
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if (size <= maxBytes) return false;
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const ext = path.extname(filePath);
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const base = filePath.slice(0, filePath.length - ext.length);
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// Drop the oldest backup if it exists, then shift each numbered backup up
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// one slot. Errors are ignored: missing intermediate backups are normal,
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// failed renames just mean we'll rotate again next time.
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try { fs.unlinkSync(`${base}.${maxBackups}${ext}`); } catch {}
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for (let i = maxBackups - 1; i >= 1; i--) {
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try { fs.renameSync(`${base}.${i}${ext}`, `${base}.${i + 1}${ext}`); } catch {}
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}
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try {
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fs.renameSync(filePath, `${base}.1${ext}`);
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log(`logRotation: rotated ${filePath} (${(size / 1024 / 1024).toFixed(1)} MB) → ${base}.1${ext}`);
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return true;
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} catch (err) {
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log(`logRotation: rename ${filePath} → ${base}.1${ext} failed: ${err.message}`);
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return false;
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}
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}
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module.exports = { maybeRotateLogFile };
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