optimize: local cache global variable and reduce string object creation.

[membphis]

and some code style.

[k8s-ci-robot]

Hi @membphis. Thanks for your PR.

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[aledbf]

/ok-to-test

[membphis]

@aledbf @ElvinEfendi Can this branch be merged?

[ElvinEfendi]

/lgtm

thanks @membphis ! would be great to add a linter to limit line length

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ElvinEfendi, membphis

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