[Artifacts] Save md5 hash for each artifact upload (#1494)

* Hash artifact upload using md5

* Add imports

* Small tweaks

* PR feedback

* PR Feedback

packages/artifact/src/internal/upload/blob-upload.ts

@@ -3,6 +3,8 @@ import {TransferProgressEvent} from '@azure/core-http'
 import {ZipUploadStream} from './zip'
 import {getUploadChunkSize} from '../shared/config'
 import * as core from '@actions/core'
+import * as crypto from 'crypto'
+import * as stream from 'stream'
 
 export interface BlobUploadResponse {
   /**
@@ -14,6 +16,11 @@ export interface BlobUploadResponse {
    * The total reported upload size in bytes. Empty if the upload failed
    */
   uploadSize?: number
+
+  /**
+   * The MD5 hash of the uploaded file. Empty if the upload failed
+   */
+  md5Hash?: string
 }
 
 export async function uploadZipToBlobStorage(
@@ -41,15 +48,31 @@ export async function uploadZipToBlobStorage(
     onProgress: uploadCallback
   }
 
+  let md5Hash: string | undefined = undefined
+  const uploadStream = new stream.PassThrough()
+  const hashStream = crypto.createHash('md5')
+
+  zipUploadStream.pipe(uploadStream) // This stream is used for the upload
+  zipUploadStream.pipe(hashStream).setEncoding('hex') // This stream is used to compute a hash of the zip content that gets used. Integrity check
+
   try {
+    core.info('Beginning upload of artifact content to blob storage')
+
     await blockBlobClient.uploadStream(
-      zipUploadStream,
+      uploadStream,
       bufferSize,
       maxBuffers,
       options
     )
+
+    core.info('Finished uploading artifact content to blob storage!')
+
+    hashStream.end()
+    md5Hash = hashStream.read() as string
+    core.info(`MD5 hash of uploaded artifact zip is ${md5Hash}`)
+
   } catch (error) {
-    core.info(`Failed to upload artifact zip to blob storage, error: ${error}`)
+    core.warning(`Failed to upload artifact zip to blob storage, error: ${error}`)
     return {
       isSuccess: false
     }
@@ -62,12 +85,9 @@ export async function uploadZipToBlobStorage(
     }
   }
 
-  core.info(
-    `Successfully uploaded all artifact file content. Total reported size: ${uploadByteCount}`
-  )
-
   return {
     isSuccess: true,
-    uploadSize: uploadByteCount
+    uploadSize: uploadByteCount,
+    md5Hash: md5Hash
   }
 }