1 files changed, 67 insertions, 0 deletions
diff --git a/container-core/src/main/java/com/yahoo/container/handler/metrics/PrometheusV1Handler.java b/container-core/src/main/java/com/yahoo/container/handler/metrics/PrometheusV1Handler.java
new file mode 100644
index 00000000000..54207e5c640
--- /dev/null
+++ b/container-core/src/main/java/com/yahoo/container/handler/metrics/PrometheusV1Handler.java
@@ -0,0 +1,67 @@
+package com.yahoo.container.handler.metrics;
+
+import ai.vespa.util.http.VespaHttpClientBuilder;
+import com.yahoo.container.jdisc.HttpResponse;
+import com.yahoo.restapi.Path;
+import com.yahoo.restapi.StringResponse;
+import com.yahoo.vespa.jdk8compat.List;
+import com.yahoo.yolean.Exceptions;
+import java.io.IOException;
+import java.net.URI;
+import java.util.Optional;
+import java.util.concurrent.Executor;
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.config.RequestConfig;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.BasicResponseHandler;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.eclipse.jetty.server.Response;
+
+import static com.yahoo.container.handler.metrics.MetricsV2Handler.consumerQuery;
+import static com.yahoo.jdisc.Response.Status.INTERNAL_SERVER_ERROR;
+
+public class PrometheusV1Handler extends HttpHandlerBase{
+
+    public static final String V1_PATH = "/prometheus/v1";
+    static final String VALUES_PATH = V1_PATH + "/values";
+
+    private static final int HTTP_CONNECT_TIMEOUT = 5000;
+    private static final int HTTP_SOCKET_TIMEOUT = 30000;
+
+    private final String prometheusProxyUri;
+    private final HttpClient httpClient = createHttpClient();
+
+    protected PrometheusV1Handler(Executor executor,
+                                  MetricsProxyApiConfig config) {
+        super(executor);
+        prometheusProxyUri = "http://localhost:" + config.metricsPort() + config.prometheusApiPath();
+    }
+
+    @Override
+    protected Optional<HttpResponse> doHandle(URI requestUri, Path apiPath, String consumer) {
+        if (apiPath.matches(V1_PATH)) return Optional.of(resourceListResponse(requestUri, List.of(VALUES_PATH)));
+        if (apiPath.matches(VALUES_PATH)) return Optional.of(valuesResponse(consumer));
+        return Optional.empty();
+    }
+
+    private HttpResponse valuesResponse(String consumer) {
+        try {
+            String uri = prometheusProxyUri + consumerQuery(consumer);
+            String prometheusText = httpClient.execute(new HttpGet(uri), new BasicResponseHandler());
+            return new StringResponse(prometheusText);
+        } catch (IOException e) {
+            log.warning("Unable to retrieve metrics from " + prometheusProxyUri + ": " + Exceptions.toMessageString(e));
+            return new ErrorResponse(INTERNAL_SERVER_ERROR, e.getMessage());
+        }
+    }
+
+    private static CloseableHttpClient createHttpClient() {
+        return VespaHttpClientBuilder.create()
+                .setUserAgent("application-prometheus-receiver")
+                .setDefaultRequestConfig(RequestConfig.custom()
+                                            .setConnectTimeout(HTTP_CONNECT_TIMEOUT)
+                                            .setSocketTimeout(HTTP_SOCKET_TIMEOUT)
+                                            .build())
+                .build();
+    }
+}