From dbc547e5cf017bfcd3cc1602115c06256d508dde Mon Sep 17 00:00:00 2001
From: Stuart Douglas <stuart.w.douglas@gmail.com>
Date: Wed, 9 Oct 2024 17:09:43 +1100
Subject: [PATCH] feat: obervability support for JVM

fixes: #3041
---
 jvm-runtime/ftl-runtime/common/deployment/pom.xml  |  4 ++++
 ...erConfigSource.java => StaticConfigSource.java} | 14 ++++++++++----
 ...rg.eclipse.microprofile.config.spi.ConfigSource |  2 +-
 jvm-runtime/ftl-runtime/common/runtime/pom.xml     |  8 ++++++++
 .../java/xyz/block/ftl/runtime/VerbHandler.java    | 12 +++++++++++-
 5 files changed, 34 insertions(+), 6 deletions(-)
 rename jvm-runtime/ftl-runtime/common/deployment/src/main/java/xyz/block/ftl/deployment/{BannerConfigSource.java => StaticConfigSource.java} (53%)

diff --git a/jvm-runtime/ftl-runtime/common/deployment/pom.xml b/jvm-runtime/ftl-runtime/common/deployment/pom.xml
index 0ba449822e..72d4d26f41 100644
--- a/jvm-runtime/ftl-runtime/common/deployment/pom.xml
+++ b/jvm-runtime/ftl-runtime/common/deployment/pom.xml
@@ -23,6 +23,10 @@
             <groupId>io.quarkus</groupId>
             <artifactId>quarkus-rest-jackson-deployment</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-opentelemetry-deployment</artifactId>
+        </dependency>
         <dependency>
             <groupId>io.quarkus</groupId>
             <artifactId>quarkus-agroal-spi</artifactId>
diff --git a/jvm-runtime/ftl-runtime/common/deployment/src/main/java/xyz/block/ftl/deployment/BannerConfigSource.java b/jvm-runtime/ftl-runtime/common/deployment/src/main/java/xyz/block/ftl/deployment/StaticConfigSource.java
similarity index 53%
rename from jvm-runtime/ftl-runtime/common/deployment/src/main/java/xyz/block/ftl/deployment/BannerConfigSource.java
rename to jvm-runtime/ftl-runtime/common/deployment/src/main/java/xyz/block/ftl/deployment/StaticConfigSource.java
index 0ce5fff4e4..220491e335 100644
--- a/jvm-runtime/ftl-runtime/common/deployment/src/main/java/xyz/block/ftl/deployment/BannerConfigSource.java
+++ b/jvm-runtime/ftl-runtime/common/deployment/src/main/java/xyz/block/ftl/deployment/StaticConfigSource.java
@@ -4,9 +4,10 @@
 
 import org.eclipse.microprofile.config.spi.ConfigSource;
 
-public class BannerConfigSource implements ConfigSource {
+public class StaticConfigSource implements ConfigSource {
 
     public static final String QUARKUS_BANNER_ENABLED = "quarkus.banner.enabled";
+    final static String OTEL_METRICS_ENABLED = "quarkus.otel.metrics.enabled";
 
     @Override
     public Set<String> getPropertyNames() {
@@ -15,14 +16,19 @@ public Set<String> getPropertyNames() {
 
     @Override
     public String getValue(String propertyName) {
-        if (propertyName.equals(QUARKUS_BANNER_ENABLED)) {
-            return "false";
+        switch (propertyName) {
+            case (QUARKUS_BANNER_ENABLED) -> {
+                return "false";
+            }
+            case OTEL_METRICS_ENABLED -> {
+                return "true";
+            }
         }
         return null;
     }
 
     @Override
     public String getName() {
-        return "Quarkus Banner";
+        return "Quarkus Static Config Source";
     }
 }
diff --git a/jvm-runtime/ftl-runtime/common/deployment/src/main/resources/META-INF/services/org.eclipse.microprofile.config.spi.ConfigSource b/jvm-runtime/ftl-runtime/common/deployment/src/main/resources/META-INF/services/org.eclipse.microprofile.config.spi.ConfigSource
index d8995dc83b..3560bbbc3a 100644
--- a/jvm-runtime/ftl-runtime/common/deployment/src/main/resources/META-INF/services/org.eclipse.microprofile.config.spi.ConfigSource
+++ b/jvm-runtime/ftl-runtime/common/deployment/src/main/resources/META-INF/services/org.eclipse.microprofile.config.spi.ConfigSource
@@ -1 +1 @@
-xyz.block.ftl.deployment.BannerConfigSource
\ No newline at end of file
+xyz.block.ftl.deployment.StaticConfigSource
\ No newline at end of file
diff --git a/jvm-runtime/ftl-runtime/common/runtime/pom.xml b/jvm-runtime/ftl-runtime/common/runtime/pom.xml
index d8b58c7940..1f0ac4cce3 100644
--- a/jvm-runtime/ftl-runtime/common/runtime/pom.xml
+++ b/jvm-runtime/ftl-runtime/common/runtime/pom.xml
@@ -24,6 +24,14 @@
             <groupId>io.quarkus</groupId>
             <artifactId>quarkus-rest-jackson</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-opentelemetry</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>io.opentelemetry.instrumentation</groupId>
+            <artifactId>opentelemetry-jdbc</artifactId>
+        </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.module</groupId>
             <artifactId>jackson-module-kotlin</artifactId>
diff --git a/jvm-runtime/ftl-runtime/common/runtime/src/main/java/xyz/block/ftl/runtime/VerbHandler.java b/jvm-runtime/ftl-runtime/common/runtime/src/main/java/xyz/block/ftl/runtime/VerbHandler.java
index 50f6fac6f1..86c77aab87 100644
--- a/jvm-runtime/ftl-runtime/common/runtime/src/main/java/xyz/block/ftl/runtime/VerbHandler.java
+++ b/jvm-runtime/ftl-runtime/common/runtime/src/main/java/xyz/block/ftl/runtime/VerbHandler.java
@@ -1,8 +1,11 @@
 package xyz.block.ftl.runtime;
 
+import io.opentelemetry.api.metrics.DoubleGauge;
 import jakarta.inject.Singleton;
 
 import io.grpc.stub.StreamObserver;
+import io.opentelemetry.api.metrics.LongCounter;
+import io.opentelemetry.api.metrics.Meter;
 import io.quarkus.grpc.GrpcService;
 import xyz.block.ftl.v1.*;
 
@@ -11,14 +14,21 @@
 public class VerbHandler extends VerbServiceGrpc.VerbServiceImplBase {
 
     final VerbRegistry registry;
+    final LongCounter counter;
 
-    public VerbHandler(VerbRegistry registry) {
+    public VerbHandler(VerbRegistry registry, Meter meter) {
         this.registry = registry;
+        counter = meter.counterBuilder("ftl-jvm-runtime/verb_invocations")
+                .setDescription("The number of verb invocations")
+                .setUnit("invocations")
+                .build();
     }
 
     @Override
     public void call(CallRequest request, StreamObserver<CallResponse> responseObserver) {
         try {
+            counter.add(1);
+
             var response = registry.invoke(request);
             responseObserver.onNext(response);
             responseObserver.onCompleted();