[FLINK-21108][rest-client] Add basic & digest auth support to rest client

[sunxiaoguang]

Signed-off-by: Xiaoguang Sun sunxiaoguang@zhihu.com

What is the purpose of the change

Implement Basic & Digest Auth scheme in rest-client so Flink rest-server can be protected behind a proxy with corresponding authentication enabled.

Brief change log

• Restart request and resend request again with corresponding authorization responses on receiving authentication challenge.
• Abstract different authentication scheme and implemented two of the most widely used authentication schemes which are Basic and Digest
• Add a special exception type RestartableException to Flink runtime concurrent package so that a task that can be restarted immediately can be handled differently in FututeUtils.java
• Add two new config options to rest client to specify username and password

Verifying this change

This change added tests and can be verified as follows:

• TODO

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

NA

Documentation

• Flink rest client can be verified against a secured proxy sitting in front of real Job Manager and makes Job Manager available to users have valid credential only.

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Automated Checks

Last check on commit 3441a04 (Thu Mar 25 05:47:29 UTC 2021)

Warnings:

• No documentation files were touched! Remember to keep the Flink docs up to date!

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Review Progress

• ❓ 1. The [description] looks good.
• ❓ 2. There is [consensus] that the contribution should go into to Flink.
• ❓ 3. Needs [attention] from.
• ❓ 4. The change fits into the overall [architecture].
• ❓ 5. Overall code [quality] is good.

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[sunxiaoguang]

I'm working on unit tests recently, comments on design and implementation about this feature is welcome. Thanks

[flinkbot]

CI report:

• 3441a04 Azure: FAILURE

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