How to execute a script located in the runner from the ci-pipeline?

Question

I have a gitlab-runner image as follows:

Dockerfile

FROM alpine:3.6

RUN apk add --no-cache curl bash

COPY trigger-jenkins /usr/local/bin/trigger-jenkins

ENTRYPOINT ["/bin/bash"]

Its purpose is to trigger a Jenkins job. Running this with:

docker run -ti jenkins-runner:latest trigger-jenkins job_name

works perfectly fine. But when I tried to do the same by:

.gitlab-ci.yml

Jenkins Trigger:
  script:
    - trigger-jenkins job_name
  tags:
    - Jenkins

The pipeline fails like this:

Running with gitlab-ci-multi-runner 9.3.0 (3df822b)
  on Jenkins Trigger (12475d61)
Using Docker executor with image jenkins-runner:latest ...
Using docker image sha256:44dedf0b3485e0e57107e2745739e1a252fb64c4161465e1b5ccc1119a1183bf for predefined container...
Using docker image jenkins-runner:latest ID=sha256:4760a8ef9139ee9c9a56c686de780fc49e176fe4294e1f0db4f431e117b6811c for build container...
Running on runner-12475d61-project-6-concurrent-0 via cc960a3794a0...
Cloning repository...
Cloning into '/builds/dev/Project'...
Checking out 874b2eac as test/jenkins...
Skipping Git submodules setup
/bin/sh: /bin/sh: cannot execute binary file
/bin/sh: /bin/sh: cannot execute binary file
ERROR: Job failed: exit code 126

I searched for the error code, but was not able to find an explanation.

What am I missing?

Answer 1

The issue was not because of exec. The issue was probably this, your entrypoint was /bin/bash and Gitlab CI was trying to execute /bin/sh which is an executable. Leads to something like below

/bin/bash /bin/sh command args

Which is what the complaint we see as. Cannot execute binary file. What your entrypoint should have been is below

ENTRYPOINT ["/bin/bash", "-c"]

Which would have made sure a command gets execute by bash and whether it is another shell or bash it would have worked. No need to modify and created entrypoint.sh

Answer 2

I continued my research and found the repository of the official maven docker images.

They solved a similar problem by creating a mvn-entrypoint.sh. So I tried the same:

entrypoint.sh

#!/bin/sh

export PATH=$PATH:/usr/local/bin/

exec "$@"

This did the trick.