Java tutorial
/* * Copyright (C) 2016 QAware GmbH * * Licensed 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 de.qaware.chronix.solr.ingestion.format; import de.qaware.chronix.timeseries.MetricTimeSeries; import org.apache.commons.lang.StringUtils; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.nio.charset.Charset; import java.time.Instant; import java.util.HashMap; import java.util.Map; import java.util.Objects; import java.util.stream.Collectors; /** * Parses the OpenTSDB telnet format. * <p> * See http://opentsdb.net/docs/build/html/user_guide/writing.html. */ public class OpenTsdbTelnetFormatParser implements FormatParser { /** * UTF-8 charset. Used for decoding the given input stream. */ private static final Charset UTF_8 = Charset.forName("utf-8"); private static final String METRIC_TYPE = "metric"; @Override public Iterable<MetricTimeSeries> parse(InputStream stream) throws FormatParseException { Map<Metric, MetricTimeSeries.Builder> metrics = new HashMap<>(); BufferedReader reader = new BufferedReader(new InputStreamReader(stream, UTF_8)); String line; try { while ((line = reader.readLine()) != null) { // Format is: put <metric> <timestamp> <value> <tagk1=tagv1[ tagk2=tagv2 ...tagkN=tagvN]> // Example: put sys.cpu.user 1356998400 42.5 host=webserver01 cpu=0 String[] parts = StringUtils.split(line, ' '); // 5 parts, because "Each data point must have at least one tag." if (parts.length < 5) { throw new FormatParseException( "Expected at least 5 parts, found " + parts.length + " in line '" + line + "'"); } if (!parts[0].equals("put")) { throw new FormatParseException( "Expected first segment to be 'put', but was '" + parts[0] + "'"); } String metricName = getMetricName(parts); Instant timestamp = getMetricTimestamp(parts); double value = getMetricValue(parts); Map<String, String> tags = getMetricTags(parts); // If the metric is already known, add a point. Otherwise create the metric and add the point. Metric metric = new Metric(metricName, tags); MetricTimeSeries.Builder metricBuilder = metrics.get(metric); if (metricBuilder == null) { metricBuilder = new MetricTimeSeries.Builder(metricName, METRIC_TYPE); for (Map.Entry<String, String> tagEntry : tags.entrySet()) { metricBuilder.attribute(tagEntry.getKey(), tagEntry.getValue()); } metrics.put(metric, metricBuilder); } metricBuilder.point(timestamp.toEpochMilli(), value); } } catch (IOException e) { throw new FormatParseException("IO exception while parsing OpenTSDB telnet format", e); } return metrics.values().stream().map(MetricTimeSeries.Builder::build).collect(Collectors.toList()); } /** * Extract the metric tags from the parts. * * @param parts Parts. * @return Metric tags. */ private Map<String, String> getMetricTags(String[] parts) throws FormatParseException { Map<String, String> tags = new HashMap<>(); for (int i = 4; i < parts.length; i++) { String tag = parts[i]; String[] tagParts = StringUtils.split(tag, "=", 2); if (tagParts.length != 2) { throw new FormatParseException( "Expected 2 tag parts, found " + tagParts.length + " in tag '" + tag + "'"); } tags.put(tagParts[0], tagParts[1]); } return tags; } /** * Extracts the metric timestamp from the parts. * * @param parts Parts. * @return Metric timestamp. * @throws FormatParseException If something went wrong while extracting. */ private Instant getMetricTimestamp(String[] parts) throws FormatParseException { String value = parts[2]; try { if (value.length() != 10 && value.length() != 13) { throw new FormatParseException( "Expected a timestamp length of 10 or 13, found " + value.length() + " ('" + value + "')"); } // 10 digits means seconds, 13 digits mean milliseconds boolean secondResolution = value.length() == 10; long epochTime = Long.parseLong(value); return secondResolution ? Instant.ofEpochSecond(epochTime) : Instant.ofEpochMilli(epochTime); } catch (NumberFormatException e) { throw new FormatParseException("Can't convert '" + value + "' to long", e); } } /** * Extracts the metric value from the given parts. * * @param parts Parts. * @return Metric value. * @throws FormatParseException If something went wrong while extracting. */ private double getMetricValue(String[] parts) throws FormatParseException { String value = parts[3]; try { return Double.parseDouble(value); } catch (NumberFormatException e) { throw new FormatParseException("Can't convert '" + value + "' to double", e); } } /** * Extracts the metric name from the given parts. * * @param parts Parts. * @return Metric name. */ private String getMetricName(String[] parts) { return parts[1]; } /** * DTO for a metric. * <p> * A metric is unique on its name and tags. */ private static class Metric { private final String name; private final Map<String, String> tags; public Metric(String name, Map<String, String> tags) { this.name = name; this.tags = tags; } @Override public boolean equals(Object o) { if (this == o) { return true; } if (o == null || getClass() != o.getClass()) { return false; } Metric metric = (Metric) o; return Objects.equals(name, metric.name) && Objects.equals(tags, metric.tags); } @Override public int hashCode() { return Objects.hash(name, tags); } } }