could support elasticsearch read time out configuration?

[wuyupengwoaini]

Recently,I got an error when run this spark-dependencies job in dokcer .
19/08/02 05:50:26 INFO ElasticsearchDependenciesJob: Running Dependencies job for 2019-08-01T00:00Z, reading from jaeger-span-2019-08-01 index, result storing to jaeger-dependencies-2019-08-01 [Stage 0:> (1 + 8) / 3040]19/08/02 05:51:31 ERROR NetworkClient: Node [[ip1:port] failed (Read timed out); selected next node [[ip1:port] 19/08/02 05:51:31 ERROR NetworkClient: Node [ip1:port] failed (Read timed out); selected next node [ip2:port] 19/08/02 05:51:31 ERROR NetworkClient: Node [ip2:port] failed (Read timed out); selected next node [ip3:port]
So,I suppose could support timeout config.
`
The following is the specific configuration

es.http.timeout (default 1m)
Timeout for HTTP/REST connections to Elasticsearch.`

https://www.elastic.co/guide/en/elasticsearch/hadoop/6.6/configuration.html

[pavolloffay]

+1 would you like to submit a PR for it?

[wuyupengwoaini]

Not only the es.http.timeout configuration and also other the cofiguration about performance such as es.scroll.size (default 50).So,I suppose that we should provide the ability for users to configure performance parameters,but I can't find a good way to do this
@pavolloffay Do you have a good idea?

[pavolloffay]

The parameters are configurable via ENV vars, just follow the approach what we use for other parameters.