| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.nifi.web.api.metrics; |
| |
| import com.fasterxml.jackson.core.JsonFactory; |
| import com.fasterxml.jackson.core.JsonGenerator; |
| import com.fasterxml.jackson.databind.ObjectMapper; |
| import io.prometheus.client.Collector; |
| import io.prometheus.client.CollectorRegistry; |
| |
| import java.io.BufferedWriter; |
| import java.io.IOException; |
| import java.io.OutputStream; |
| import java.io.OutputStreamWriter; |
| import java.io.Writer; |
| import java.util.Collection; |
| import java.util.Enumeration; |
| |
| /** |
| * Prometheus Metrics Writer with Json output format and optional filtering |
| */ |
| public class JsonFormatPrometheusMetricsWriter extends AbstractPrometheusMetricsWriter { |
| private final String rootFieldName; |
| |
| public JsonFormatPrometheusMetricsWriter(final String sampleName, final String sampleLabelValue, final String rootFieldName) { |
| super(sampleName, sampleLabelValue); |
| this.rootFieldName = rootFieldName == null ? "samples" : rootFieldName; |
| } |
| |
| @Override |
| public void write(final Collection<CollectorRegistry> registries, final OutputStream outputStream) throws IOException { |
| JsonFactory factory = new JsonFactory(); |
| try (final Writer writer = new BufferedWriter(new OutputStreamWriter(outputStream)); |
| final JsonGenerator generator = factory.createGenerator(writer)) { |
| generator.setCodec(new ObjectMapper()); |
| generator.writeStartObject(); |
| generator.writeFieldName(rootFieldName); |
| generator.writeStartArray(); |
| for (final CollectorRegistry collectorRegistry : registries) { |
| final Enumeration<Collector.MetricFamilySamples> samples = getSamples(collectorRegistry); |
| while (samples.hasMoreElements()) { |
| final Collector.MetricFamilySamples samples2 = samples.nextElement(); |
| for (Collector.MetricFamilySamples.Sample sample : samples2.samples) { |
| generator.writeObject(sample); |
| generator.flush(); |
| } |
| generator.flush(); |
| } |
| } |
| generator.writeEndArray(); |
| generator.writeEndObject(); |
| generator.flush(); |
| } |
| } |
| } |