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https://issues.apache.org/jira/browse/HBASE-11025?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13974964#comment-13974964
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ryan rawson commented on HBASE-11025:
-------------------------------------
I'm specifically talking about this line of code:
+ consensus = ConsensusProviderFactory.getConsensusProvider(conf);
Here you are referencing a global (ConsensusProviderFactory). The idea is
instead of calling it here, you'd augment the constructor with:
public HRegionServer(/* stuff */,
ConsensusProviderFactory
consensusProviderFactory);
then later on:
consensus = consensusProviderFactory.getConsensusProvider(conf);
the implementation of the factory then checks the conf, as the code currently
does, to figure out how to build a ConsenusProvider.
This helps Unit tests because we can provide a mocked ConsensusProviderFactory
(right now it's a class, it would become an Interface, and there'd be a
'ConfigSwitchedConsensusProviderFactory' concrete class that'd be provided at
the production points of HRS construction.
While seemingly a complication, I think the provision for easier testability
and less reliance on global factory methods is a big plus. For a reference,
check out "Clean Code" Chapter 11.
> Infrastructure for pluggable consensus service
> ----------------------------------------------
>
> Key: HBASE-11025
> URL: https://issues.apache.org/jira/browse/HBASE-11025
> Project: HBase
> Issue Type: Sub-task
> Components: Zookeeper
> Reporter: Mikhail Antonov
> Assignee: Mikhail Antonov
> Attachments: HBASE-11025.patch
>
>
> Related to HBASE-10915.
> In this jira I will extract the changed for property changes, factory and
> consensus provider interface (+ZK implementation), as it's going to be
> required by other subtasks of HBASE-10909.
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