feat(target-gh): Check asset MD5 hash by downloading the asset

src/targets/github.ts

@@ -378,12 +378,30 @@ export class GithubTarget extends BaseTarget {
         );
       }
 
-      // XXX: This is a bit hacky as we rely on two things:
-      // 1. GitHub issuing a redirect to S3, where they store the artifacts,
-      //    or at least pass those request headers unmodified to us
-      // 2. AWS S3 using the MD5 hash of the file for its ETag cache header
-      //    when we issue a HEAD request.
-      const response = await this.github.request(`HEAD ${url}`, {
+      const remoteChecksum = await this.getRemoteChecksum(url);
+      const localChecksum = createHash('md5').update(file).digest('hex');
+      if (localChecksum !== remoteChecksum) {
+        throw new Error(
+          `Uploaded asset MD5 checksum does not match local asset checksum for "${name} (${localChecksum} != ${remoteChecksum})`
+        );
+      }
+      return url;
+    } catch (e) {
+      uploadSpinner.fail(`Cannot upload asset "${name}".`);
+
+      throw e;
+    }
+  }
+
+  private async getRemoteChecksum(url: string): Promise<string> {
+    // XXX: This is a bit hacky as we rely on two things:
+    // 1. GitHub issuing a redirect to S3, where they store the artifacts,
+    //    or at least pass those request headers unmodified to us
+    // 2. AWS S3 using the MD5 hash of the file for its ETag cache header
+    //    when we issue a HEAD request.
+    let response;
+    try {
+      response = await this.github.request(`HEAD ${url}`, {
         headers: {
           // WARNING: You **MUST** pass this accept header otherwise you'll
           //          get a useless JSON API response back, instead of getting
@@ -395,32 +413,37 @@ export class GithubTarget extends BaseTarget {
           Accept: DEFAULT_CONTENT_TYPE,
         },
       });
+    } catch (e) {
+      throw new Error(
+        `Cannot get asset on GitHub. Status: ${(e as any).status}\n` + e
+      );
+    }
 
+    const etag = response.headers['etag'];
+    if (etag && etag.length > 0) {
       // ETag header comes in quotes for some reason so strip those
-      const remoteChecksum = response.headers['etag']?.slice(1, -1);
-      if (remoteChecksum) {
-        // XXX: This local checksum calculation only holds for simple cases:
-        // https://github.com/getsentry/craft/issues/322#issuecomment-964303174
-        const localChecksum = createHash('md5').update(file).digest('hex');
-        if (localChecksum !== remoteChecksum) {
-          logger.trace(`Checksum mismatch for "${name}"`, response.headers);
-          throw new Error(
-            `Uploaded asset MD5 checksum does not match local asset checksum for "${name} (${localChecksum} != ${remoteChecksum})`
-          );
-        }
-        uploadSpinner.succeed(`Uploaded asset "${name}".`);
-      } else {
-        logger.warn(`Response headers:`, response.headers);
-        uploadSpinner.succeed(
-          `Uploaded asset "${name}, but failed to find a remote checksum. Cannot verify uploaded file is as expected.`
-        );
-      }
-      return url;
-    } catch (e) {
-      uploadSpinner.fail(`Cannot upload asset "${name}".`);
+      return etag.slice(1, -1);
+    }
 
-      throw e;
+    return await this.md5FromUrl(url);
+  }
+
+  private async md5FromUrl(url: string): Promise<string> {
+    this.logger.debug('Downloading asset from GitHub to check MD5 hash: ', url);
+    let response;
+    try {
+      response = await this.github.request(`GET ${url}`, {
+        headers: {
+          Accept: DEFAULT_CONTENT_TYPE,
+        },
+      });
+    } catch (e) {
+      throw new Error(
+        `Cannot download asset from GitHub. Status: ${(e as any).status}\n` + e
+      );
     }
+
+    return createHash('md5').update(Buffer.from(response.data)).digest('hex');
   }
 
   private async handleGitHubUpload(