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 or
extracted artifacts, let's make use of this to ensure that the expected
number of bytes was written to disk.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

.vscode/settings.json

@@ -6,6 +6,7 @@
     ],
     "cSpell.words": [
         "Backoff",
+        "artifactsize",
         "autodrain",
         "dpkg",
         "localpath",

__tests__/downloader.test.ts

@@ -214,6 +214,6 @@ test('can obtain build ID', async () => {
     'git-sdk-64-minimal',
     undefined
   )
-  expect(fetch).toHaveBeenCalledTimes(1)
+  expect(fetch).toHaveBeenCalledTimes(2)
   expect(cacheId).toEqual('git-for-windows.git-22-git-sdk-64-minimal-73427')
 })

main.ts

@@ -5,7 +5,13 @@ import {readdirSync, unlinkSync} from 'fs'
 
 async function run(): Promise<void> {
   try {
-    const {artifactName, stripPrefix, download, cacheId} = await get(
+    const {
+      artifactName,
+      stripPrefix,
+      download,
+      bytesToExtract,
+      cacheId
+    } = await get(
       core.getInput('repository'),
       core.getInput('definitionId'),
       core.getInput('artifact'),
@@ -35,6 +41,7 @@ async function run(): Promise<void> {
           if (await restoreCache([storeZipAs], cacheId)) {
             await unzip(
               `file:${storeZipAs}`,
+              bytesToExtract,
               stripPrefix,
               outputDirectory,
               verbose

src/downloader.ts

@@ -31,6 +31,7 @@ function mkdirp(directoryPath: string): void {
 
 export async function unzip(
   url: string,
+  bytesToExtract: number,
   stripPrefix: string,
   outputDirectory: string,
   verbose: boolean | number,
@@ -86,12 +87,21 @@ export async function unzip(
             entry.autodrain()
           } else {
             progress(entryPath)
-            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(files))
+        .on('finish', () => {
+          bytesToExtract === 0
+            ? resolve(files)
+            : // eslint-disable-next-line prefer-promise-reject-errors
+              reject(`${bytesToExtract} bytes left to extract`)
+        })
     }
     if (url.startsWith('file:')) {
       callback(fs.createReadStream(url.substring('file:'.length)))
@@ -109,6 +119,7 @@ export async function get(
 ): Promise<{
   artifactName: string
   stripPrefix: string
+  bytesToExtract: number
   cacheId: string
   download: (
     outputDirectory: string,
@@ -131,11 +142,15 @@ export async function get(
   if (data.count !== 1) {
     throw new Error(`Unexpected number of builds: ${data.count}`)
   }
-  let url: string | undefined
-  const getURL = async (): Promise<string> => {
+  const getURL = async (): Promise<{url: string; bytesToExtract: number}> => {
     const data2 = await fetchJSONFromURL<{
       count: number
-      value: [{name: string; resource: {downloadUrl: string}}]
+      value: [
+        {
+          name: string
+          resource: {downloadUrl: string; properties: {artifactsize: number}}
+        }
+      ]
     }>(`${baseURL}/${data.value[0].id}/artifacts`)
     if (!artifactName) {
       if (data2.value.length !== 1) {
@@ -155,13 +170,15 @@ export async function get(
           .join(', ')}`
       )
     }
-    return filtered[0].resource.downloadUrl
-  }
 
-  if (!artifactName) {
-    url = await getURL()
+    return {
+      url: filtered[0].resource.downloadUrl,
+      bytesToExtract: filtered[0].resource.properties.artifactsize
+    }
   }
 
+  const {url, bytesToExtract} = await getURL()
+
   if (!stripPrefix) {
     stripPrefix = `${artifactName}/`
   }
@@ -171,14 +188,12 @@ export async function get(
     verbose: number | boolean = false,
     storeZipAs?: string
   ): Promise<string[]> => {
-    if (!url) {
-      url = await getURL()
-    }
     let delayInSeconds = 1
     for (;;) {
       try {
         return await unzip(
           url,
+          bytesToExtract,
           stripPrefix || `${artifactName}/`,
           outputDirectory,
           verbose,
@@ -203,5 +218,5 @@ export async function get(
     '/',
     '.'
   )
-  return {artifactName, stripPrefix, download, cacheId}
+  return {artifactName, stripPrefix, download, bytesToExtract, cacheId}
 }