Downloading App Engine source code

So it seems from a few SO questions I've seen that this is a problem among other users. Recently one of our head dev's left and I inherited a lot of his projects. One of which, is a website that what seems like lives on an app engine from google cloud platforms. From the App Engine documentation, to download source code you use the appcfg.py download_app command. Which I did, however the only results I get back from that call is:

Fetching file list...
Fetching files...

And then it just ends. No error message or any kind of message at all, and of course, it did not download the source code into the output dir I specified.

Scratching my head and looking at various SO posts, someone mentioned something about going into the google cloud vm directly and doing the same command, and to my surprise finding the same exact behavior that I did in my local terminal.

This made me realize it must be something else at play. I took a look at my versions tab in the App Engine dashboard on GCP. I see my instance running, it correctly says Serving and if I click the link it brings me to the website which loads fine. However, under Size it says 0 B which made me think perhaps this is why the download_app isn't downloading anything, because the version is 0 B?

What I'm trying to figure out is why it says 0 B for the version, when clearly the site runs fine and how I can get the source code for this. Here's a screenshot for reference

And screenshot of my terminal (local). Obviously I omitted the -A and -V flags, but they are correctly set and if I purposely make them incorrect I do indeed get an error message.

EDIT

Just so everyone is aware, I also made sure my user had the correct permissions. Owner, App Engine Owner... and some others. I don't think that's the problem.

Solution 1:

When you deploy an App Engine Flexible application, the source code is uploaded to Cloud Storage on your project in a bucket named staging.<project-id>.appspot.com. You can navigate in this bucket and download the source code for a specific version as a .tar file.

Alternatively, you can find the exact Cloud Storage URL for your source code by going to Dev Console > Container Registry > Build History and select the build for your version. You'll find the link to your source code under Build Information.

One thing to note however is that the staging... bucket is created by default with a Lifecycle rule that deletes files older than 15 days automatically. You can delete this rule if you want so that all versions' source code is kept indefinitely.

In your case I believe that may not have helped since files may have been deleted already but it's worth knowing you can get the source code from there (source code isn't pushed to Source Repository by default, your developer had to configure it manually).

Solution 2:

In the developer console you can select the respective project and check:

• on the Services page - which services, AKA modules - as they used to be (and still are) called in various places, you app has deployed
• on the Versions page - which versions for each of the services are deployed

This information is what appcfg.py download_app expects. See also:

• the various appcfg.py options using its --help flag
• How do I download a specific service's source code off of AppEngine?

You can also access the deployed source code live (if everything else fails it could still be a last resort method to get the code, but tedious), see my answer to Google Cloud DataStore automatic indexing

Update:

I just now noticed in your screenshot that it's a flexible environment app. The appcfg.py docs are in the standard environment section, I suspect it's not applicable to the flexible environment, for which what's deployed is actually a docker image built during the deployment operation. From Deploying your application:

Deploy your app to App Engine using the gcloud app deploy command. This command automatically builds a container image by using the Container Builder service and then deploys that image to the App Engine flexible environment. The container will include any local modifications that you've made to the runtime image.

It might be possible to access the code on the actual GCE instance running the app, by connecting to the running instance and starting a shell in your app container, see Connecting to the instance

Solution 3:

Posting this since none of the listed methods on the web didn't take me to the code (by June 2021)

Note: appcfg.py is deprecated by Google

You could try accessing your source code through;

Google Cloud Platform > Debugger > choosing the version of the Application from combo at top.

This will list the files of that version on the left pane. There is no way to download code automatically but you can copy-paste the code.

Advice: Push your code to a Git repository to avoid this hassle next time.

Hope you will find this helpful.