Added websocket subscription metrics

Author: oliemansm

README.md

@@ -290,6 +290,17 @@ graphql:
     servlet:
         actuator-metrics: true
 ```
+
+## Usage
+See [Baeldung Spring Boot Actuators](https://www.baeldung.com/spring-boot-actuators) for the basics of using Actuator. 
+Add `spring-boot-starter-actuator` to your project as dependency.
+
+The following metrics are available for exposure:
+* `graphql.timer.query`
+* `graphql.websocket.sessions` - number of active websocket sessions for subscriptions
+* `graphql.websocket.subscriptions` - number of active subscriptions 
+
+
 # Contributions
 
 Contributions are welcome.  Please respect the [Code of Conduct](http://contributor-covenant.org/version/1/3/0/).

gradle.properties

@@ -17,7 +17,7 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #
 
-version = 5.8.1
+version = 5.9.0-SNAPSHOT
 PROJECT_GROUP = com.graphql-java-kickstart
 PROJECT_NAME = graphql-spring-boot
 PROJECT_DESC = GraphQL Spring Framework Boot
@@ -40,7 +40,7 @@ LIB_GRAPHQL_JAVA_VER = 12.0
 LIB_JUNIT_VER = 4.12
 LIB_SPRING_CORE_VER = 5.0.4.RELEASE
 LIB_SPRING_BOOT_VER = 2.1.4.RELEASE
-LIB_GRAPHQL_SERVLET_VER = 7.4.1
+LIB_GRAPHQL_SERVLET_VER = 7.5.0-SNAPSHOT
 LIB_GRAPHQL_JAVA_TOOLS_VER = 5.6.0
 LIB_COMMONS_IO_VER = 2.6
 kotlin.version=1.3.10

graphql-spring-boot-autoconfigure/src/main/java/com/oembedler/moon/graphql/boot/GraphQLInstrumentationAutoConfiguration.java

@@ -2,10 +2,13 @@
 
 import com.oembedler.moon.graphql.boot.metrics.MetricsInstrumentation;
 import com.oembedler.moon.graphql.boot.metrics.TracingNoResolversInstrumentation;
+import com.oembedler.moon.graphql.boot.metrics.WebsocketMetrics;
 import graphql.analysis.MaxQueryComplexityInstrumentation;
 import graphql.analysis.MaxQueryDepthInstrumentation;
 import graphql.execution.instrumentation.tracing.TracingInstrumentation;
+import graphql.servlet.GraphQLWebsocketServlet;
 import io.micrometer.core.instrument.MeterRegistry;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.export.simple.SimpleMetricsExportAutoConfiguration;
@@ -18,11 +21,13 @@
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
+import javax.annotation.PostConstruct;
+
 /**
  * @author Marcel Overdijk
  */
 @Configuration
-@AutoConfigureAfter({MetricsAutoConfiguration.class, SimpleMetricsExportAutoConfiguration.class})
+@AutoConfigureAfter({MetricsAutoConfiguration.class, SimpleMetricsExportAutoConfiguration.class, GraphQLWebsocketAutoConfiguration.class})
 @ConditionalOnProperty(value = "graphql.servlet.enabled", havingValue = "true", matchIfMissing = true)
 @EnableConfigurationProperties({GraphQLServletProperties.class})
 public class GraphQLInstrumentationAutoConfiguration {
@@ -74,4 +79,12 @@ public MetricsInstrumentation metricsInstrumentation(MeterRegistry meterRegistry
         return new MetricsInstrumentation(meterRegistry, Boolean.TRUE.toString().equals(tracingEnabled));
     }
 
+    @Bean
+    @ConditionalOnProperty(value = "graphql.servlet.actuator-metrics", havingValue = "true")
+    @ConditionalOnBean({MeterRegistry.class, GraphQLWebsocketServlet.class})
+    @ConditionalOnMissingBean
+    public WebsocketMetrics websocketMetrics(MeterRegistry meterRegistry, GraphQLWebsocketServlet websocketServlet) {
+        return new WebsocketMetrics(meterRegistry, websocketServlet);
+    }
+
 }

graphql-spring-boot-autoconfigure/src/main/java/com/oembedler/moon/graphql/boot/metrics/WebsocketMetrics.java

@@ -0,0 +1,18 @@
+package com.oembedler.moon.graphql.boot.metrics;
+
+import graphql.servlet.GraphQLWebsocketServlet;
+import io.micrometer.core.instrument.Gauge;
+import io.micrometer.core.instrument.MeterRegistry;
+
+public class WebsocketMetrics {
+
+    public WebsocketMetrics(MeterRegistry meterRegistry, GraphQLWebsocketServlet websocketServlet) {
+        Gauge.builder("graphql.websocket.sessions", websocketServlet, GraphQLWebsocketServlet::getSessionCount)
+                .description("Active websocket sessions available for subscriptions")
+                .register(meterRegistry);
+        Gauge.builder("graphql.websocket.subscriptions", websocketServlet, GraphQLWebsocketServlet::getSubscriptionCount)
+                .description("Active websocket subscriptions")
+                .register(meterRegistry);
+    }
+
+}