GitHub user StephanEwen opened a pull request:
https://github.com/apache/flink/pull/2605
[DISCUSS] Introduce config options
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.
## 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
## Example
Simple option:
```java
Option<String> TASK_MANAGER_TMP_DIRS = new Option<>(
"taskmanager.tmp.dirs", // config key
System.getProperty("java.io.tmpdir")); // default value
```
Option with multiple deprecated keys:
```java
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
```
Get a config value, this automatically checks deprecated keys and default
values:
```java
final String zkQuorum =
configuration.getValue(ConfigOptions.HA_ZOOKEEPER_QUORUM);
final long connTimeout =
configuration.getInteger(ConfigOptions.HA_ZOOKEEPER_CONN_TIMEOUT);
```
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/StephanEwen/incubator-flink config_options
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/2605.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #2605
----
commit 4cb894b25cc7558501af8d537db737c5646c752f
Author: Stephan Ewen <[email protected]>
Date: 2016-10-06T17:38:09Z
[FLINK-XXXX] [core] Introduce config options
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