Do verify that the expected amount of bytes were written

Helpfully, Azure Pipelines reports an "artifact size", which is the
total number of bytes to be extracted to disk.

Since we had occasional problems due to incompletely
downloaded/extracted artifacts (most lately,
https://github.com/microsoft/git/runs/2218601656?check_suite_focus=true#step:3:9),
let's make use of this to ensure that the expected number of bytes was
written to disk.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

.vscode/settings.json

@@ -13,6 +13,7 @@
         "Backoff",
         "MSYSTEM",
         "Pacman",
+        "artifactsize",
         "autodrain",
         "unzipper",
         "vercel"

src/downloader.ts

@@ -36,6 +36,7 @@ function mkdirp(directoryPath: string): void {
 
 async function unzip(
   url: string,
+  bytesToExtract: number,
   stripPrefix: string,
   outputDirectory: string,
   verbose: boolean | number,
@@ -88,12 +89,21 @@ async function unzip(
               mkdirp(entryPath.replace(/\/$/, ''))
               entry.autodrain()
             } else {
-              entry.pipe(fs.createWriteStream(`${entryPath}`))
+              entry
+                .pipe(fs.createWriteStream(`${entryPath}`))
+                .on('finish', () => {
+                  bytesToExtract -= fs.statSync(entryPath).size
+                })
             }
           })
           .on('error', reject)
           .on('finish', progress)
-          .on('finish', resolve)
+          .on('finish', () => {
+            bytesToExtract === 0
+              ? resolve()
+              : // eslint-disable-next-line prefer-promise-reject-errors
+                reject(`${bytesToExtract} bytes left to extract`)
+          })
       })
       .on('error', reject)
   })
@@ -231,7 +241,12 @@ export async function get(
   ): Promise<void> => {
     const data2 = await fetchJSONFromURL<{
       count: number
-      value: [{name: string; resource: {downloadUrl: string}}]
+      value: [
+        {
+          name: string
+          resource: {downloadUrl: string; properties: {artifactsize: number}}
+        }
+      ]
     }>(`${baseURL}/${data.value[0].id}/artifacts`)
     const filtered = data2.value.filter(e => e.name === artifactName)
     if (filtered.length !== 1) {
@@ -240,11 +255,13 @@ export async function get(
       )
     }
     const url = filtered[0].resource.downloadUrl
+    const bytesToExtract = filtered[0].resource.properties.artifactsize
     let delayInSeconds = 1
     for (;;) {
       try {
         await unzip(
           url,
+          bytesToExtract,
           `${artifactName}/`,
           outputDirectory,
           verbose,