Jenkins Shell脚本未收到作业参数的新值

Question

I'm observing strange unexpected behavior and want your advice, whether it's a bug in Jenkins/Jenkins plugin, or I'm missing the point and should use Jenkins differently.

My task:

I got a freestyle project with an optionally set string parameter.

If the user specifies a value for this parameter, build should use this value. If the user didn't specify a value, build should compute a value and use it.

The resulting value should be used in several other build steps, including shell scripts and triggered builds on other projects.

The shortened list of build steps that I have is:

1. Execute shell

    [ -n "$VERSION" ] && echo "VERSION=$VERSION" > new_env || echo "VERSION=12345" > new_env 

2. Inject environment variables, Properties File Path: new_env

3. Execute shell

    foo "$VERSION" 

4. Trigger/call builds on other project using predefined parameters: upstream_version=$VERSION

Problem:

Now, if the user does not specify a value for VERSION ,

• shell script at step 3 receives an empty value (WRONG! well, at least unexpected to me)
• build on other project called with upstream_version=12345 (correct)

Feels pretty strange - why does the triggered build receive the new value and the shell script doesn't?

Jenkins version is 1.625.3.

Answer 1

What you need is a way to check if variable is defined and not-empty. Bash has built in for it. (-z)

if [ -z "$VAR" ];

More details at question in server fault question: How to determine if a bash variable is empty?