In the run.sh script, why are there backticks around the startup command?

[timvlaer]

See

amazon-kinesis-data-processor-aws-fargate/consumer/run.sh

Line 4 in 147ca29

`python3 /usr/bin/amazon_kclpy_helper.py --print_command --java /usr/bin/java --properties /usr/bin/sample.properties --log-configuration /usr/bin/logback.xml` &

I am confused by the syntax with backticks. I thought it is an old way of writing $() to evaluate something inline and use the output in the command itself. But since this command on line 4 is not nested, I wonder what the added value is.

It also distracts from the super important & at the end which makes sure the command is ran in the background so the script continues to the tail of the log. (If you don't run it in the background, there's no logging at all.)

I understand the MultiLangDaemon uses stdin and stdout for communication with the python process. Is that the reason the python process itself cannot run as the main process?

[timvlaer]

I can confirm the backticks are required to get some logging out of the container, but my question remains, what does it so that this somehow works?

[timvlaer]

I think I get it now, the amazon_kclpy_helper script outputs the command that needs to be executed, hence the backticks.

Now, following SC2091 and SC2092, I propose to write it like this:

command=$(python3 /usr/local/lib/python3.9/site-packages/samples/amazon_kclpy_helper.py --print_command --java /usr/bin/java -p /usr/bin/record_processor.properties --log-configuration /usr/bin/logback.xml)
eval "$command" &

[timvlaer]

I opened PR #16 with these proposals included.