[FLINK-17023][scripts] Fix format checking of extractExecutionParams in config.sh

[tsreaper]

What is the purpose of the change

In FLINK-15727 BashJavaUtils now returns multiple lines of results to avoid using BashJavaUtils twice. But now the format checking for the last line is incorrect.

This PR fixes the format checking for the last line in extractExecutionParams in config.sh.

Brief change log

• Fix format checking of extractExecutionParams in config.sh

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn/Mesos, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

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Last check on commit 59e7e20 (Thu Apr 16 03:15:22 UTC 2020)

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[zentol]

Not sure I understand the problem, extractExecutionParams is only ever called for a single line.

jvm_params=$(extractExecutionParams "$(echo "$params_output" | head -n 1)")
dynamic_configs=$(extractExecutionParams "$(echo "$params_output" | tail -n 1)")

[tsreaper]

Not sure I understand the problem, extractExecutionParams is only ever called for a single line.

jvm_params=$(extractExecutionParams "$(echo "$params_output" | head -n 1)")
dynamic_configs=$(extractExecutionParams "$(echo "$params_output" | tail -n 1)")

OK I didn't notice that extractExecutionParams is only called for a single line. So shall we add this restriction to extractExecutionParams and change its error message? I'm submitting this PR because I feed multiple lines to extractExecutionParams in my code and get the error message saying that the format of my last line is incorrect, which is not the case.

[zentol]

that would make more sense, yes.

[tillrohrmann]

I think this change broke my local setup. If I build from master I can no longer start a cluster via bin/start-cluster.sh.

[tillrohrmann]

I think the problem is that we don't do proper trimming.

[tillrohrmann]

I think this change broke the standalone cluster setup because wc -l returns a number with a preceding tab.

[tillrohrmann]

An easy fix could be to prepend | xargs echo but I'm not sure whether we can assume that xargs is installed on all systems.

[leonardBang]

@tillrohrmann same error in my macOS ...
I think using if ! [[ ${num_lines} -eq 1 ]] to check number also works
I'd like to fix the soon

[leonardBang]

@wangyang0918 has opened a PR #11820