temporarily add back use metrics for the operator-served SDKs

src/main/java/com/uid2/operator/vertx/ClientVersionCapturingHandler.java

@@ -0,0 +1,52 @@
+package com.uid2.operator.vertx;
+
+import com.uid2.shared.Const;
+import io.micrometer.core.instrument.Counter;
+import io.micrometer.core.instrument.Metrics;
+import io.vertx.core.Handler;
+import io.vertx.ext.web.RoutingContext;
+
+import java.io.IOException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.HashMap;
+import java.util.Map;
+
+public class ClientVersionCapturingHandler implements Handler<RoutingContext> {
+    private final Map<String, Counter> _clientVersionCounters = new HashMap<>();
+
+    public ClientVersionCapturingHandler(String dir, String whitelistGlob) throws IOException {
+        try (DirectoryStream<Path> dirStream = Files.newDirectoryStream(Paths.get(dir), whitelistGlob)) {
+            dirStream.forEach(path -> {
+                final String version = getFileNameWithoutExtension(path);
+                final Counter counter = Counter
+                        .builder("uid2.client_sdk_versions")
+                        .description("counter for how many http requests are processed per each client sdk version")
+                        .tags("client_version", version)
+                        .register(Metrics.globalRegistry);
+                _clientVersionCounters.put(version, counter);
+            });
+        }
+    }
+    @Override
+    public void handle(RoutingContext context) {
+        String clientVersion = context.request().headers().get(Const.Http.ClientVersionHeader);
+        if (clientVersion == null) {
+            clientVersion =  !context.queryParam("client").isEmpty() ? context.queryParam("client").get(0) : null;
+        }
+        if (clientVersion != null) {
+            final Counter counter = _clientVersionCounters.get(clientVersion);
+            if (counter != null) {
+                counter.increment();
+            }
+        }
+        context.next();
+    }
+
+    private static String getFileNameWithoutExtension(Path path) {
+        final String fileName = path.getFileName().toString();
+        return fileName.indexOf(".") > 0 ? fileName.substring(0, fileName.lastIndexOf(".")) : fileName;
+    }
+}

src/main/java/com/uid2/operator/vertx/UIDOperatorVerticle.java

@@ -218,6 +218,7 @@ private Router createRoutesSetup() throws IOException {
 
         router.allowForward(AllowForwardHeaders.X_FORWARD);
         router.route().handler(new RequestCapturingHandler());
+        router.route().handler(new ClientVersionCapturingHandler("static/js", "*.js"));
         router.route().handler(CorsHandler.create()
                 .addRelativeOrigin(".*.")
                 .allowedMethod(io.vertx.core.http.HttpMethod.GET)