Apache Geode - Creating region on DUnit Based Test Server/Remote Server with same code from client

Question

I am tryint to reuse the code in following documentation : https://geode.apache.org/docs/guide/11/developing/region_options/dynamic_region_creation.html

The first problem that i met is that

Cache cache = CacheFactory.getAnyInstance();
Region<String,RegionAttributes<?,?>> regionAttributesMetadataRegion = createRegionAttributesMetadataRegion(cache);

should not be executed in constructor. In case it is , the code is executed in client instance , it is failed on not server error.When this fixed i receive

[fatal 2021/02/15 16:38:24.915 EET <ServerConnection on port 40527 Thread 1> tid=81] Serialization filter is rejecting class org.restcomm.cache.geode.CreateRegionFunction
java.lang.Exception: 
at org.apache.geode.internal.ObjectInputStreamFilterWrapper.lambda$createSerializationFilter$0(ObjectInputStreamFilterWrapper.java:233)

The problem is that code is getting executed on dunit MemberVM and the required class is actually the part of the package under which the test is getting executed. So i guess i should somehow register the classes ( or may be jar ) separately to dunit MemberVM. How it can be done?

Another question is: currently the code is checking if the region exists and if not it calls the method. In both cases it also tries to create the clientRegion. The question is whether this is a correct approach?

Region<?,?> cache = instance.getRegion(name);
if(cache==null) {
    Execution execution = FunctionService.onServers(instance);
    ArrayList argList = new ArrayList();
    argList.add(name);
    Function function = new CreateRegionFunction();
    execution.setArguments(argList).execute(function).getResult();
}

ClientRegionFactory<Object, Object> cf=this.instance.createClientRegionFactory(ClientRegionShortcut.CACHING_PROXY).addCacheListener(new ExtendedCacheListener());
this.cache = cf.create(name);

BR Yulian Oifa

Answer 1

The first problem that i met is that Cache cache = CacheFactory.getAnyInstance(); should not be executed in constructor. In case it is , the code is executed in client instance , it is failed on not server error.When this fixed i receive

Once the Function is registered on server side, you can execute it by ID instead of sending the object across the wire (so you won't need to instantiate the function on the client), in which case you'll also avoid the Serialization filter error. As an example, FunctionService.onServers(instance).execute(CreateRegionFunction.ID).

The problem is that code is getting executed on dunit MemberVM and the required class is actually the part of the package under which the test is getting executed. So i guess i should somehow register the classes ( or may be jar ) separately to dunit MemberVM. How it can be done?

Indeed, for security reasons Geode doesn't allow serializing / deserializing arbitrary classes. Internal Geode distributed tests use the MemberVM and set a special property (serializable-object-filter) to circumvent this problem. Here's an example of how you can achieve that within your own tests.

Another question is: currently the code is checking if the region exists and if not it calls the method. In both cases it also tries to create the clientRegion. The question is whether this is a correct approach?

If the dynamically created region is used by the client application then yes, you should create it, otherwise you won't be able to use it.

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As a side note, there's a lot of internal logic implemented by Geode when creating a Region so I wouldn't advice to dynamically create regions on your own. Instead, it would be advisable to use the gfsh create region command directly, or look at how it works internally (see here) and try to re-use that.