I don’t think there is such hook in the Flink code now. You will have to walk around this issue somehow in user space.
Maybe you could make a contract that every operator before touching Guice, should call static synchronized method `initializeGuiceContext`. This method could search the classpath for classes with some specific annotations, for example `@MyInitializationHook` and install/add all of such hooks before actually using Guice? Piotrek > On 21 Dec 2017, at 17:49, Steven Wu <stevenz...@gmail.com> wrote: > > We use Guice for dependency injection. We need to install additional Guice > modules (for bindings) when setting up this static context of Guice injector. > > Calling the static initializer from operator open method won't really help. > Not all operators are implemented by app developer who want to install > additional Guice modules. E.g. kafka source operator is implemented/provided > by our platform. I think the source operator will open first, which means app > operator won't get a chance to initialize the static context. What would > really help if there is a entry hook (at task manager) that is executed > before any operator opening. > > On Thu, Dec 21, 2017 at 12:27 AM, Piotr Nowojski <pi...@data-artisans.com > <mailto:pi...@data-artisans.com>> wrote: > Open method is called just before any elements are processed. You can hook in > any initialisation logic there, including initialisation of a static context. > However keep in mind, that since this context is static, it will be shared > between multiple operators (if you are running parallelism > number of task > managers), so accesses to it must be synchronized (including initialisation). > Another thing to consider is that managing the life cycle of static context > can be tricky (when to close it and release it’s resources). > > The questions is, whether you really need a static context? > > Thanks, > Piotrek > > > > On 21 Dec 2017, at 07:53, Steven Wu <stevenz...@gmail.com > > <mailto:stevenz...@gmail.com>> wrote: > > > > Here is my understanding of how job submission works in Flink. When > > submitting a job to job manager via REST API, we provide a entry class. Job > > manager then evaluate job graph and ship serialized operators to task > > manager. Task manager then open operators and run tasks. > > > > My app would typically requires some initialization phase to setup my own > > running context in task manager (e.g. calling a static method of some > > class). Does Flink provide any entry hook in task manager when executing a > > job (and tasks)? As for job manager, the entry class provides such hook > > where I can initialize my static context. > > > > Thanks, > > Steven > >
