You can use the AWS CLI to get a description of existing resources. This description is in JSON format, which can sometimes directly be used as a Cloudformation template.
aws glue get-job --job-name MyJobName
Makes the job easier! For example with the Glue job, we can see the undocumented options
"--enable-metrics": "" "--TempDir": "s3://blablubbtest" "--enable-continuous-cloudwatch-log": "true"
So since Cloudformation is a pain to debug, a possible way to write a template might be to click together the resources with the Console, then get the description with the CLI and use this to create the resources with Cloudformation next time.