Is it possible to recover builder-stage source code from an active Fly.io Docker deployment?

[tarantababu]

Hi everyone,

I have a Fly.io application deployed using a multi-stage Docker build.

The local source code is no longer available, so I attempted to recover it from the currently running Fly.io deployment. I was able to pull the active runtime image and successfully run the app locally, but the original source code is missing.

From my investigation:

• The final image only contains runtime/build artifacts

• The builder stage (where COPY . . and build happened) is not present in the final image

• docker history, docker save, and layer inspection confirm that source files are not included

• It appears Fly.io only stores the final optimized image, not intermediate stages

My questions:

1. Does Fly.io retain any access to builder-stage layers or intermediate images after deployment?

2. Is there any Fly.io-specific mechanism (internal registry, cache, previous releases, etc.) to retrieve builder-stage contents?

3. If not, can you confirm that in a standard multi-stage Docker deploy, source code recovery is fundamentally impossible once only the final image exists?

I mainly want to confirm whether this limitation is absolute or if there is any Fly.io-specific recovery option I may have missed.

Thanks in advance.

[halfer]

@tarantababu

The local source code is no longer available

Normally this happens when there’s been an argument about intellectual property, and someone has kicked another person off the code hosting platform. May I ask what happened? Readers will want to know if you’ve taken someone’s work without paying them.

If not, can you confirm that in a standard multi-stage Docker deploy, source code recovery is fundamentally impossible once only the final image exists?

Your three questions are essentially the same: can you recover the source code? It may depend on what technology you use. If it’s PHP or Ruby, then probably yes; if it’s Go or Java or C++, then no. Node/JS is sort of a middle ground, as it is likely to be minified.