Gutenberg PR Preview: Broken check for the build artifact availability

[WunderBart]

The endpoint for checking the zipped build availability returns a different payload depending on the artifact availability, but it's always a 200:

Request	Artifact unavailable	Artifact available
Code	200	200
Payload	JSON: { "error": "Request failed" }	zip file

The code that validates the artifact availability checks only whether it's a 200 or not, meaning it always passes that check. The consequence is that a wrong error is thrown, which can be misleading:

JavaScript Error: Error when executing the blueprint step #2 ({"step":"writeFile","path":"/wordpress/pr/pr.zip","data":{"resource":"url","url":"/plugin-proxy.php?org=WordPress&repo=gutenberg&workflow=Build%20Gutenberg%20Plugin%20Zip&artifact=gutenberg-plugin&pr=59242","caption":"Downloading Gutenberg PR 59242"},"progress":{"weight":2,"caption":"Applying Gutenberg PR 59242"}}) : Could not download "/plugin-proxy.php?org=WordPress&repo=gutenberg&workflow=Build%20Gutenberg%20Plugin%20Zip&artifact=gutenberg-plugin&pr=59242".
Check if the URL is correct and the server is reachable.
If it is reachable, the server might be blocking the request.

The correct error thrown should be:

The PR 12345 does not exist or GitHub CI did not finish building it yet.

[bgrgicak]

@brandonpayton I could use your help with this one because it looks like a server issue.

Production

I get a 200 and an empty plugin-proxy.php is downloaded.

https://playground.wordpress.net/plugin-proxy.php?org=WordPress&repo=gutenberg&workflow=Build%20Gutenberg%20Plugin%20Zip&artifact=gutenberg-plugin&pr=59242&verify_only=true

Locally

Start a server:

cd packages/playground/website/public/
php -S localhost:4321 -d .

I get a 400 error as expected.

http://localhost:4321/plugin-proxy.php?org=WordPress&repo=gutenberg&workflow=Build%20Gutenberg%20Plugin%20Zip&artifact=gutenberg-plugin&pr=59242&verify_only=true

[adamziel]

@bgrgicak are you setting GITHUB_TOKEN locally?

[adamziel]

The problem here is that the /plugin-proxy.php?verify_only=yes request short-circuits with HTTP 200 when it finds an artifact:

wordpress-playground/packages/playground/website/public/plugin-proxy.php

Line 95 in 0fbbcba

if (array_key_exists('verify_only', $_GET)) {

Whereas the /plugin-proxy.php request tries to fetch that artifact and, in doing so, may fail if the actual file is not available.

This diff seems to solve it:

diff --git a/packages/playground/website/public/plugin-proxy.php b/packages/playground/website/public/plugin-proxy.php
index 59f9522afb..b1a55216a4 100644
--- a/packages/playground/website/public/plugin-proxy.php
+++ b/packages/playground/website/public/plugin-proxy.php
@@ -87,16 +87,6 @@ class PluginDownloader
                 continue;
             }
 
-            /*
-             * Short-circuit with HTTP 200 OK when we only want to
-             * verify whether the CI artifact seems to exist but we
-             * don't want to download it yet.
-             */
-            if (array_key_exists('verify_only', $_GET)) {
-                header('HTTP/1.1 200 OK');
-                return;
-            }
-
             $allowed_headers = array(
                 'content-length',
                 'content-disposition',
@@ -112,6 +102,16 @@ class PluginDownloader
             ob_end_flush();
             flush();
 
+            /*
+             * Short-circuit with HTTP 200 OK when we only want to
+             * verify whether the CI artifact seems to exist but we
+             * don't want to download it yet.
+             */
+            if (array_key_exists('verify_only', $_GET)) {
+                header('HTTP/1.1 200 OK');
+                return;
+            }
+
             // The API endpoint returns the actual artifact URL as a 302 Location header.
             foreach ($artifact_res['headers'] as $header_line) {
                 $header_name = strtolower(substr($header_line, 0, strpos($header_line, ':')));

Any takes to make it into a PR?