You can pass context variables from the parent job to a child job but not the contrary. At the end of your child job, you can send theses informations in a tBufferOutput. In the parent job, you will get the data in the flow, after the tRunJob. You can then, with a tContextLoad, put theses values in the context, and transmit it to the log job.
Talend : Passing Parameters and Variables to Subjob You can send context variable or globalMap variables from parent to child job , here is the easiest way Create the context variable name in the child job. In tRunjob , go on component tab and : Select which variable you want to send , you can for example send the Whole context. “Transmit whole context” is used to transmit all the context variables of a parent job to a child job….