Core: Expose max HTTP body size control

docs/config.md

@@ -44,6 +44,7 @@ The next sections describes how to set up project configuration.
 - `circuitbreaker.closed_state_calls_number` - size of circuit breaker sliding window.
 - `circuitbreaker.half_open_state_calls_number` - number of calls in half open state.
 - `sampling.rate` - logging sampling rate
+- `server.max-http-body-size-kb` - sets max HTTP body size in kb. Default is 256 kb. Improper usage might lead to application running out of memory.
 
 ### Storage
 - `storage.default-ttl-seconds` - set the default ttl for the data

src/main/java/org/prebid/cache/config/BodySizeConfig.java

@@ -0,0 +1,20 @@
+package org.prebid.cache.config;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.codec.ServerCodecConfigurer;
+import org.springframework.web.reactive.config.WebFluxConfigurer;
+
+@Configuration
+@ConditionalOnProperty(name = "server.max-http-body-size-kb")
+public class BodySizeConfig implements WebFluxConfigurer {
+
+    @Value("${server.max-http-body-size-kb}")
+    private int maxHttpBodySizeKb;
+
+    @Override
+    public void configureHttpMessageCodecs(ServerCodecConfigurer configurer) {
+        configurer.defaultCodecs().maxInMemorySize(maxHttpBodySizeKb * 1024);
+    }
+}