Runner doesn't work with transcrypt(Git file encryption)

Hi,

I use transcrypt to encrypt a private key inside my repository. Transcrypt is a simple bash script which uses openssl to encrypt/decrypt the files. During the deployment phase of my build I initialize the repository with transcrypt. This changes the git config and it creates additional files in the .git directory.

This works for one build. On the second build it uses the cached repository with the changed git config and the added files. The problem is now that git tries to encrypt the private key during checkout. And it seems that the runner cannot execute openssl during checkout.

Running with gitlab-ci-multi-runner 1.8.1 (a2efdd4)
Using Docker executor with image setusoft/scala-sbt-nodejs:latest ...
Using locally found image version with exactly the same ID
Pulling docker image setusoft/scala-sbt-nodejs:latest ...
Running on runner-76873a67-project-1509-concurrent-0 via sys01cirun1...
Fetching changes...
Removing build/files/deployment.config
Removing target/
.git/crypt/clean: line 16: openssl: command not found
.git/crypt/clean: line 17: openssl: command not found
error: external filter "$(git rev-parse --git-dir)"/crypt/clean %f failed -1
error: external filter "$(git rev-parse --git-dir)"/crypt/clean %f failed
fatal: build/files/deployment.key: clean filter 'crypt' failed
ERROR: Build failed: exit code 1

The host on which the runner runs, as also the docker image has openssl installed. Any idea what can cause this issue?

Thanks in advance! Christian