Would it help to be able to register "initializers", meaning some
classes/methods that will be called at every process entry point, to set up
something like this?
On Tue, Mar 13, 2018 at 7:56 PM, Steven Wu <stevenz...@gmail.com> wrote:
> Xiaochuan,
>
> We are doing exactly as you described. We keep the injector as a global
> static var.
>
> But we extend from FlinkJobManager and FlinkTaskManager to override main
> method and initialize the injector (and other things) during JVM startup,
> which does cause tight code coupling. It is a little painful to upgrade
> Flink because sometimes internal code structure change of FlinkJobManager
> and FlinkTaskManager can break our extended class..
>
> Thanks,
> Steven
>
>
> On Tue, Mar 13, 2018 at 11:30 AM, XiaoChuan Yu <xiaochuan...@kik.com>
> wrote:
>
>> Hi,
>>
>> I'm evaluating Flink with the intent to integrate it into a Java project
>> that uses a lot of dependency injection via Guice. What would be the best
>> way to work with DI/Guice given that injected fields aren't Serializable?
>> I looked at this StackOverflow answer so far. To my understanding the
>> strategy is as follows but I'm not sure about step 3:
>>
>> 1. Use a RichFunction any time injection required.
>> 2. Do not use @Inject, instead mark each injected field as transient.
>> 3. Implement open() / close() and manually assign values to injected
>> fields using Injector.getInstance(SomeClass.class)? But where do I
>> get the injector? Create one on the spot each time? Keep one as a static
>> var somewhere and use everywhere?
>>
>> Example:
>> public class MyFilter extends FilterFunction<String> {
>> private transient DbClient dbClient;
>> //@Inject DbClient dbClient; //typical Guice field injection
>>
>> public void open(Configuration parameters) {
>> // where am I suppose to get the injector?
>> // keep it as a static variable somewhere and init it in Main?
>> this.dbClient = MyInjectorHolder.injector().ge
>> tInstance(DbClient.class);
>> }
>> public boolean filter(String value) {
>> return this.dbClient.query(value);
>> }
>> }
>> I haven't setup a Flink environment to try the above yet though.
>> Does anyone know of a less verbose way?
>> I imagine this could get quite verbose with multiple injected fields.
>>
>> Thanks,
>> Xiaochuan Yu
>>
>>
>
