Caffeine with reactive mongo Template

[Kamal5999]

private final AsyncLoadingCache<String, IGroovyScript> scriptCache;

public ScriptCache(ScriptRepository scriptRepository) {
        this.scriptRepository = scriptRepository;
        scriptCache = Caffeine.newBuilder()
                .maximumSize(200)
                .recordStats()
                .buildAsync(new ScriptCacheLoader());
    }

private class ScriptCacheLoader implements CacheLoader<String, CompletableFuture<IGroovyScript>> {

        @Override
        public  IGroovyScript load(@NonNull String key) throws Exception {
            log.error("load method has being called");
            return  scriptRepository.findScriptByKey(key)
                    .doOnError(err -> log.error("Error while fetching data from repository : ", err))
                    .doOnSuccess(script -> log.info("data with key {} is loaded successfully",key))
                    .block();
        }
    }

My scriptRepository.findScriptByKey(key) returns Mono<> but i don't want to apply block as this is reactive, what can i do to make AsyncLoadingCache<String, IGroovyScript> scriptCache or even LoadingCache<> without blocking

[Kamal5999]

I have tried with LoadingCache<String, Mono> scriptCache;
but this results in hitting mongo everytime on get even if it is present although caffeine stats show cacheMiss only 1 time, but checked with mongo logs , hit is going everytime on get.

[ben-manes]

Can you try Mono.fromFuture(future) with an async cache? e.g. return Mono.fromFuture(cache.get(key))

[Kamal5999]

Yes i can do that in get Method, but the issue is at load Method , how can i do load without block on Mono.

[ben-manes]

oh, I thought it was return from the cache. You can use Mono.toFuture() to return in an AsyncCacheLoader

[ben-manes]

private class ScriptCacheLoader implements AsyncCacheLoader<String, IGroovyScript> {
    @Override
    public  CompletableFuture<IGroovyScript> asyncLoad(@NonNull String key) throws Exception {
        log.error("load method has being called");
        return  scriptRepository.findScriptByKey(key)
                .doOnError(err -> log.error("Error while fetching data from repository : ", err))
                .doOnSuccess(script -> log.info("data with key {} is loaded successfully",key))
                .toFuture();
    }
}