Check size delta before vs. after hierarchical GC for approximate cleanup size

Author: haggholm

lib/tmp.js

@@ -698,10 +698,8 @@ function setLogger(logger) {
 
 async function withSubdir(prefix, fn, options) {
   const ctx = prefixStackStorage.getStore();
-  const tmpDir = path.resolve(
-    ctx ? ctx.value : _getTmpDir(),
-    prefix
-  );
+  const base = ctx ? ctx.value : _getTmpDir();
+  const tmpDir = path.resolve(base, prefix);
   const logTags = {
     ...(options && options.logTags ? options.logTags : {}),
     path: tmpDir
@@ -716,9 +714,18 @@ async function withSubdir(prefix, fn, options) {
     const cleanup = async () => {
       _logger.info(logTags,"lib-tmp.gc.start");
       const t0 = Date.now();
+      const stat0 = await fsp.statfs(base);
       try {
         await fsp.rm(tmpDir, { force: true, recursive: true, maxRetries: 5 });
-        _logger.info({ ...logTags, duration: Date.now() - t0 }, "lib-tmp.gc.end");
+        const stat1 = await fsp.statfs(base);
+        _logger.info(
+          {
+            ...logTags,
+            duration: Date.now() - t0,
+            size: (stat1.bavail - stat0.bavail) * stat0.bsize
+          },
+          "lib-tmp.gc.end"
+        );
       } catch (error) {
         _logger.info({ ...logTags, duration: Date.now() - t0, error }, "lib-tmp.gc.error");
       }