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https://issues.apache.org/jira/browse/FLINK-4764?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Stephan Ewen resolved FLINK-4764.
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Resolution: Implemented
Implemented in cdebb0ef100179e810f6e110b974632bd49c653f
> Introduce config options
> ------------------------
>
> Key: FLINK-4764
> URL: https://issues.apache.org/jira/browse/FLINK-4764
> Project: Flink
> Issue Type: Improvement
> Components: Core
> Affects Versions: 1.1.2
> Reporter: Stephan Ewen
> Assignee: Stephan Ewen
> Fix For: 1.2.0
>
>
> It is a bit unorthodox to start a discussion via a pull request, but this
> suggestion is best motivated via some code.
> I suggest to move away from the current model with `ConfigConstants` and move
> to a model where an `Option` object describes a configuration option
> completely, with default value, fallback keys.
> h2. Advantages
> - Much simpler / easier access to values that have deprecated keys
> - Not possible to accidentally overlook deprecated keys
> - Key and default values are grouped together in the definition
> - Clearly states the expected type value for each config key (string, int,
> etc).
> - We can improve this even further to include the description and
> auto-generate the config docs
> h2. Example
> Simple option:
> {code}
> Option<String> TASK_MANAGER_TMP_DIRS = new Option<>(
> "taskmanager.tmp.dirs", // config key
> System.getProperty("java.io.tmpdir")); // default value
> {code}
> Option with multiple deprecated keys:
> {code}
> Option<String> HA_CLUSTER_ID = new Option<>(
> "high-availability.cluster-id", // config key
> null, // no default value
> "high-availability.zookeeper.path.namespace", // latest
> deprecated key
> "recovery.zookeeper.path.namespace"); // even
> earlier deprecated key
> {code}
> Get a config value, this automatically checks deprecated keys and default
> values:
> {code}
> final String zkQuorum =
> configuration.getValue(ConfigOptions.HA_ZOOKEEPER_QUORUM);
> final long connTimeout =
> configuration.getInteger(ConfigOptions.HA_ZOOKEEPER_CONN_TIMEOUT);
> {code}
> h2. Multiple Options classes
> To avoid having one huge class (like `ConfigConstants`), we can easily split
> this up into `TaskManagerOptions`, `JobManagerOptions`, `ZooKeeperOptions`,
> etc.
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