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/*
* Copyright (c) 2000, 2021, Oracle and/or its affiliates.
*
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
package com.tangosol.internal.metrics;
import com.oracle.coherence.common.base.Exceptions;
import com.oracle.coherence.common.base.Logger;
import com.sun.net.httpserver.Headers;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.tangosol.coherence.config.Config;
import com.tangosol.net.metrics.MBeanMetric;
import com.tangosol.util.SimpleMapEntry;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.net.URI;
import java.net.URLDecoder;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Predicate;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import java.util.zip.GZIPOutputStream;
import static java.util.stream.Collectors.toList;
/**
* Metrics Rest http endpoint
*
* @author jk 2019.06.24
* @since 12.2.1.4.0
*/
public class MetricsHttpHandler
implements HttpHandler
{
// ----- constructors ---------------------------------------------------
/**
* Create a MetricsResource.
*
* This constructor will be used by Coherence to create the resource instance.
*
* The {@code coherence.metrics.legacy.names} system property will be used to
* determine whether legacy metric names ot Microprofile compatible metric
* names will be used when publishing Prometheus formatted metrics.
*/
public MetricsHttpHandler()
{
this(defaultFormat());
}
/**
* Create a MetricsResource.
*
* @param format the format to use for metric names and tag keys.
*/
MetricsHttpHandler(Format format)
{
f_format = format;
}
// ----- accessors ------------------------------------------------------
/**
* Returns the {@link Format} being used for metric names.
*
* @return the {@link Format} being used for metric names
*/
public Format getFormat()
{
return f_format;
}
// ----- HttpHandler methods --------------------------------------------
@Override
public void handle(HttpExchange exchange) throws IOException
{
try
{
URI requestURI = exchange.getRequestURI();
Map> mapQuery = getQueryParameters(requestURI);
Headers headers = exchange.getRequestHeaders();
String sSuffix = null;
String sName = null;
List listExtended = mapQuery.remove("extended");
boolean fExtended = f_fAlwaysUseExtended
|| listExtended != null && !listExtended.isEmpty()
&& Boolean.parseBoolean(listExtended.get(0));
// The path will always start with "/metrics" but may have *anything* after that
// as the JDK http server is not fussy
String sPath = requestURI.getPath();
if (sPath.equals("/metrics") || sPath.startsWith("/metrics/"))
{
// path is valid so far, as it is either /metrics or /metrics/......
// strip any .suffix which can be used to override the accepted media type
if (sPath.endsWith(".txt"))
{
sSuffix = ".txt";
sPath = sPath.substring(0, sPath.length() - 4);
}
else if (sPath.endsWith(".json"))
{
sSuffix = ".json";
sPath = sPath.substring(0, sPath.length() - 5);
}
// will be 2 or longer, first element is empty string
// valid length is 2, 3, or 4 if 4 is empty
String[] asSegment = sPath.split("/");
if (asSegment.length > 4 || (asSegment.length == 4 && asSegment[3].length() != 0))
{
// the path is invalid, so send 404
send(exchange, 404);
return;
}
if (asSegment.length >= 3)
{
// we have a metric name in the path i.e. /metrics/foo
sName = asSegment[2];
}
}
else
{
// the path is invalid, so send 404
send(exchange, 404);
return;
}
Predicate predicate = createPredicate(sName, mapQuery);
MetricsFormatter formatter;
if (".txt".equals(sSuffix))
{
formatter = getPrometheusMetrics(predicate, fExtended);
}
else if (".json".equals(sSuffix))
{
formatter = getJsonMetrics(predicate, fExtended);
}
else
{
formatter = getFormatterForAcceptedType(headers, predicate, fExtended);
}
if (formatter == null)
{
// no valid media types in the "Accept" header or path suffix
send(exchange, 415);
return;
}
boolean fGzip = false;
String sEncoding = headers.getFirst("Accept-Encoding");
if (sEncoding != null)
{
fGzip = Arrays.stream(sEncoding.split(","))
.map(String::trim)
.anyMatch("gzip"::equalsIgnoreCase);
}
try (OutputStream os = exchange.getResponseBody())
{
exchange.getResponseHeaders().set("Content-Type", formatter.getContentType());
if (fGzip)
{
sendGZippedMetrics(exchange, os, formatter);
}
else
{
sendMetrics(exchange, () -> os, formatter);
}
}
}
catch (Throwable t)
{
Logger.err(t);
exchange.sendResponseHeaders(500, -1);
}
}
// ----- helper methods -------------------------------------------------
/**
* Returns the query parameters present in the URI.
*
* @param uri the {@link URI} to get the query parameters from
*
* @return the map of query parameters from the URI, or an empty map if there
* were no query parameters
*/
private Map> getQueryParameters(URI uri)
{
String sQuery = uri.getQuery();
if (sQuery == null || sQuery.length() == 0)
{
return Collections.emptyMap();
}
return Arrays.stream(sQuery.split("&"))
.map(this::splitQueryParameter)
.filter(e -> e.getValue() != null)
.collect(Collectors.groupingBy(Map.Entry::getKey, LinkedHashMap::new,
Collectors.mapping(Map.Entry::getValue, Collectors.toList())));
}
/**
* Split the specified key/value query parameter into a {@link Map.Entry}
* decoding any encoded characters in the query parameter value.
*
* @param sParam the query parameter to decode
*
* @return the query parameter decoded into a {@link Map.Entry}
*/
private Map.Entry splitQueryParameter(String sParam)
{
try
{
int nIndex = sParam.indexOf("=");
String sKey = nIndex > 0 ? sParam.substring(0, nIndex) : sParam;
String sValue = nIndex > 0 && sParam.length() > nIndex + 1 ? sParam.substring(nIndex + 1) : null;
String sDecoded = sValue == null ? null : URLDecoder.decode(sValue, "UTF-8");
return new SimpleMapEntry<>(URLDecoder.decode(sKey, "UTF-8"), sDecoded);
}
catch (UnsupportedEncodingException e)
{
throw Exceptions.ensureRuntimeException(e);
}
}
/**
* Returns the {@link MetricsFormatter} matching the media type in any Accept header
* present in the request.
*
* @param headers the http request headers
* @param predicate the optional {@link Predicate} to pass to the {@link MetricsFormatter}
* @param fExtended the extended flag to the {@link MetricsFormatter}
*
* @return the {@link MetricsFormatter} matching the media type in any Accept header
* present in the request or {@code null} if there is no Accept header or
* no {@link MetricsFormatter} matches the header
*/
private MetricsFormatter getFormatterForAcceptedType(Headers headers,
Predicate predicate,
boolean fExtended)
{
List listAccept = headers.get("Accept");
if (listAccept == null)
{
return getPrometheusMetrics(predicate, fExtended);
}
else
{
for (String sType : listAccept)
{
String[] asType = sType.split(",");
for (String sAccept : asType)
{
int nIndex = sAccept.indexOf(';');
if (nIndex >= 0)
{
sAccept = sAccept.substring(0, nIndex);
}
switch (sAccept.trim())
{
case APPLICATION_JSON:
return getJsonMetrics(predicate, fExtended);
case TEXT_PLAIN:
case WILDCARD:
return getPrometheusMetrics(predicate, fExtended);
}
}
}
}
return null;
}
/**
* Send the metrics response.
* This method uses a {@link StreamSupplier} to supply the {@link OutputStream} to send the metrics data to.
* This is because we must send the response headers before sending any output data but if using an output
* stream such as {@link GZIPOutputStream} this sends dat aas soon as it is constructed. By using a supplier
* we can delay construction of any stream and hence sending any data until after this method has sent the
* response headers.
*
* @param exchange the {@link HttpExchange} to send the response to
* @param supplier a {@link StreamSupplier} to supply the {@link OutputStream} to send the metrics data to
* @param formatter the {@link MetricsFormatter} to format the response
*
* @throws IOException if an error occurs sending the response
*/
private void sendMetrics(HttpExchange exchange, StreamSupplier supplier, MetricsFormatter formatter)
throws IOException
{
exchange.sendResponseHeaders(200, 0);
try (Writer writer = new OutputStreamWriter(supplier.get()))
{
formatter.writeMetrics(writer);
writer.flush();
}
}
/**
* Send the metrics response using gzip to compress the metrics data.
*
* This method will wrap the specified {@link OutputStream} in a {@link GZIPOutputStream}
* before sending data.
*
* @param exchange the {@link HttpExchange} to send the response to
* @param os the {@link OutputStream} to send the metrics data to
* @param formatter the {@link MetricsFormatter} to format the response
*
* @throws IOException if an error occurs sending the response
*/
private void sendGZippedMetrics(HttpExchange exchange, OutputStream os, MetricsFormatter formatter)
throws IOException
{
exchange.getResponseHeaders().set("Content-Encoding", "gzip");
sendMetrics(exchange, () -> new GZIPOutputStream(os), formatter);
}
/**
* Send a simple http response.
*
* @param t the {@link HttpExchange} to send the response to
* @param status the response status
*/
private static void send(HttpExchange t, int status) {
try {
t.sendResponseHeaders(status, 0);
try (OutputStream os = t.getResponseBody()) {
os.write(EMPTY_BODY);
}
}
catch (IOException e) {
e.printStackTrace();
}
}
/**
* Obtain the current Prometheus metrics data.
*
* If the {@code sName} argument is {@code null} or an empty string, all metrics will be returned.
*
* If the {@code sName} argument is not {@code null} and not empty, all metrics matching the specified
* name will be returned. Metrics can be further filtered by specifying query parameters.
* Each name/value pair in the query parameters is used to match the metric tag values of the metrics returned.
* Not all of a metrics tags need to be specified, matching is only done on the tags specified in the query
* parameters, the metric will match even if it has extra tags not specified in the query parameters.
*
* @return the current Prometheus metrics data
*/
protected MetricsFormatter getPrometheusMetrics(Predicate predicate, boolean fExtended)
{
return new PrometheusFormatter(fExtended, f_format, getMetrics(predicate));
}
/**
* Obtain the current JSON formatted metrics data for all metrics.
*
* If the {@code sName} argument is {@code null} or an empty string, all metrics will be returned.
*
* If the {@code sName} argument is not {@code null} and not empty, all metrics matching the specified
* name will be returned. Metrics can be further filtered by specifying query parameters.
* Each name/value pair in the query parameters is used to match the metric tag values of the metrics returned.
* Not all of a metrics tags need to be specified, matching is only done on the tags specified in the query
* parameters, the metric will match even if it has extra tags not specified in the query parameters.
*
* @return the current JSON formatted metrics data for all metrics
*/
protected MetricsFormatter getJsonMetrics(Predicate predicate, boolean fExtended)
{
return new JsonFormatter(fExtended, getMetrics(predicate));
}
/**
* Determine the metric format to use based on system properties.
*
* @return the metric format to use based on system properties
*/
static Format defaultFormat()
{
if (Config.getBoolean(PROP_USE_MP_NAMES, false))
{
return Format.Microprofile;
}
else if (Config.getBoolean(PROP_USE_DOT_NAMES, false))
{
return Format.DotDelimited;
}
// Legacy names, whilst deprecated, are still the default until two releases after deprecation.
// Once we can switch to default names as the real default we can change the line below to use
// if (Config.getBoolean(PROP_USE_LEGACY_NAMES, false))
else if (Config.getBoolean(PROP_USE_LEGACY_NAMES, true))
{
return Format.Legacy;
}
return Format.Default;
}
/**
* Returns the lst of metrics matching the predicate, or all metrics if
* the predicate is {@code null}.
*
* @param predicate the optional predicate to use to filter the returned metrics
*
* @return the lst of metrics matching the predicate, or all metrics if
* the predicate is {@code null}
*/
private List getMetrics(Predicate predicate)
{
try
{
Stream> stream
= DefaultMetricRegistry.getRegistry().stream();
if (predicate != null)
{
stream = stream.filter(e -> predicate.test(e.getValue()));
}
return stream.map(Map.Entry::getValue).collect(toList());
}
catch (Throwable t)
{
Logger.err("Exception in MetricsResource.getMetrics():", t);
throw t;
}
}
/**
* Create a {@link MetricPredicate} from a metric name pattern and tags.
*
* @param sName the optional metric name pattern to use in the predicate
* @param mapTags the optional tags to use in the predicate
*
* @return the {@link MetricPredicate} to use or {@code null} if neither the name
* nor the tags are specified
*/
private MetricPredicate createPredicate(String sName, Map> mapTags)
{
if ((sName == null || sName.isEmpty()) && mapTags.isEmpty())
{
return null;
}
return new MetricPredicate(sName, mapTags);
}
// ----- inner class: MetricPredicate -----------------------------------
/**
* A {@link Predicate} that can be used to restrict the metrics returned by a request.
*/
private static class MetricPredicate
implements Predicate
{
/**
* Create a predicate.
*
* @param sName the value to use to match a metric name
* @param mapTags the values to use to match a metric tags
*/
private MetricPredicate(String sName, Map> mapTags)
{
f_sName = sName;
f_mapTags = mapTags.entrySet()
.stream()
.filter(e -> !e.getKey().equalsIgnoreCase("extended"))
.collect(Collectors.toMap(Map.Entry::getKey, e -> e.getValue().get(0)));
}
// ----- Predicate methods ------------------------------------------
@Override
public boolean test(MBeanMetric metric)
{
return hasValue(metric) && nameMatches(metric) && tagsMatch(metric);
}
// ----- helper methods ---------------------------------------------
/**
* Returns {@code true} if the metric has a non-null value.
*
* @param metric the metric to check
*
* @return {@code true} if the metric has a non-null value
*/
private boolean hasValue(MBeanMetric metric)
{
return metric.getValue() != null;
}
/**
* Returns {@code true} if the metric name matches this predicate.
*
* @param metric the metric to check
*
* @return {@code true} if the metric name matches this predicate
*/
private boolean nameMatches(MBeanMetric metric)
{
return f_sName == null || metric.getName().startsWith(f_sName);
}
/**
* Returns {@code true} if the metric tags matches this predicate.
*
* @param metric the metric to check
*
* @return {@code true} if the metric tags matches this predicate
*/
private boolean tagsMatch(MBeanMetric metric)
{
if (f_mapTags == null || f_mapTags.isEmpty())
{
return true;
}
Map mapTags = metric.getTags();
for (String sKey : f_mapTags.keySet())
{
if (!f_mapTags.get(sKey).equals(mapTags.get(sKey)))
{
return false;
}
}
return true;
}
// ----- data members -----------------------------------------------
private final String f_sName;
private final Map f_mapTags;
}
// ----- inner class: PrometheusFormatter -------------------------------
/**
* A {@link MetricsFormatter} implementation that writes metrics
* in a Prometheus format.
*/
static class PrometheusFormatter
implements MetricsFormatter
{
// ---- constructors ------------------------------------------------
/**
* Construct {@code PrometheusFormatter} instance.
*
* @param fExtended the flag specifying whether to include metric type
* and description into the output
* @param format the format to use for metric names and tag keys.
* @param listMetrics the list of metrics to write
*/
PrometheusFormatter(boolean fExtended, Format format, List listMetrics)
{
f_fExtended = fExtended;
f_format = format;
f_listMetrics = listMetrics;
}
// ---- MetricsFormatter interface ----------------------------------
@Override
public String getContentType()
{
return TEXT_PLAIN;
}
@Override
public void writeMetrics(Writer writer) throws IOException
{
for (MBeanMetric metric : f_listMetrics)
{
writeMetric(writer, metric);
writer.flush();
}
}
// ----- helper methods ---------------------------------------------
/**
* Write the metric.
*
* @param writer the {@link Writer} to write to
* @param metric the metric to write
*
* @throws IOException if an error occurs writing the metric
*/
private void writeMetric(Writer writer, MBeanMetric metric) throws IOException
{
Object oValue = metric.getValue();
if (oValue != null)
{
MBeanMetric.Identifier id = metric.getIdentifier();
Map mapTag = id.getPrometheusTags();
String sName;
switch (f_format)
{
case Legacy:
sName = id.getLegacyName();
break;
case Microprofile:
sName = id.getMicroprofileName();
break;
case DotDelimited:
sName = id.getFormattedName();
break;
default:
sName = id.getFormattedName().replaceAll("\\.", "_");
}
if (f_fExtended)
{
writeType(writer, sName);
writeHelp(writer, sName, metric.getDescription());
}
writer.append(sName);
writeTags(writer, mapTag);
writer.append(' ')
.append(oValue.toString())
.append('\n');
}
}
/**
* Write the metric type line.
*
* @param writer the {@link Writer} to write to
* @param sName the metric name
*
* @throws IOException if an error occurs writing the type line
*/
private void writeType(Writer writer, String sName) throws IOException
{
writer.append("# TYPE ").append(sName.trim()).append(" gauge\n");
}
/**
* Write the metric help description.
*
* @param writer the {@link Writer} to write to
* @param sName the metric name
* @param sDescription the metric help description
*
* @throws IOException if an error occurs writing the help description
*/
private void writeHelp(Writer writer, String sName, String sDescription) throws IOException
{
if (sDescription != null && sDescription.length() > 0)
{
writer.append("# HELP ")
.append(sName)
.append(' ')
.append(sDescription)
.append('\n');
}
}
/**
* Write the metric tags.
*
* @param writer the {@link Writer} to write the tags to
* @param mapTags the metric tags to write
*
* @throws IOException if an error occurs writing the tags
*/
private void writeTags(Writer writer, Map mapTags) throws IOException
{
if (!mapTags.isEmpty())
{
writer.write('{');
Iterator> iterator = mapTags.entrySet().iterator();
while (iterator.hasNext())
{
Map.Entry tag = iterator.next();
writer.append(tag.getKey())
.append("=\"")
.append(tag.getValue())
.append('"');
if (iterator.hasNext())
{
writer.append(", ");
}
}
writer.write('}');
}
}
// ---- data members ------------------------------------------------
/**
* The flag specifying whether to include metric type and description
* into the output.
*/
private final boolean f_fExtended;
/**
* The format to use for metric names and tag keys.
*/
private final Format f_format;
/**
* The list of metrics to write.
*/
private final List f_listMetrics;
}
// ----- inner class: JsonFormatter -------------------------------------
/**
* A {@link MetricsFormatter} implementation that writes metrics
* in a JSON format.
*/
static class JsonFormatter
implements MetricsFormatter
{
// ---- constructors ------------------------------------------------
/**
* Construct {@code JsonFormatter} instance.
*
* @param fExtended the flag specifying whether to include metric type
* and description into the output
* @param metrics the list of metrics to write
*/
JsonFormatter(boolean fExtended, List metrics)
{
f_fExtended = fExtended;
f_metrics = metrics;
}
// ---- MetricsFormatter interface ----------------------------------
@Override
public String getContentType()
{
return APPLICATION_JSON;
}
@Override
public void writeMetrics(Writer writer) throws IOException
{
writer.write('[');
boolean separator = false;
for (MBeanMetric metric : f_metrics)
{
separator = writeMetric(writer, metric, separator) || separator;
}
writer.write(']');
}
// ----- helper methods ---------------------------------------------
/**
* Write the metric as a json object.
*
* @param writer the {@link Writer} to write the json to
* @param metric the metric to write
* @param fSeparator {@code true} to indicate that a comma separator should precede
* the metric json object
*
* @throws IOException if an error occurs writing the tags
*/
private boolean writeMetric(Writer writer, MBeanMetric metric, boolean fSeparator) throws IOException
{
Object oValue = metric.getValue();
if (oValue != null)
{
MBeanMetric.Identifier id = metric.getIdentifier();
if (fSeparator)
{
writer.write(',');
}
writer.write('{');
writer.write("\"name\":\"");
writer.write(id.getName());
writer.write("\",");
writeTags(writer, id.getTags());
writer.write("\"scope\":\"");
writer.write(id.getScope().name());
writer.write("\",");
writer.write("\"value\":");
if (oValue instanceof Number || oValue instanceof Boolean)
{
writer.write(String.valueOf(oValue));
}
else
{
writer.write('"');
writer.write(String.valueOf(oValue));
writer.write('"');
}
String sDesc = metric.getDescription();
if (f_fExtended && sDesc != null && sDesc.length() > 0)
{
writer.write(',');
writer.write("\"description\":\"");
writer.write(sDesc);
writer.write('"');
}
writer.write('}');
return true;
}
return false;
}
/**
* Write the metric tags as a json object.
*
* @param writer the {@link Writer} to write the json to
* @param mapTags the metric tags to write
*
* @throws IOException if an error occurs writing the tags
*/
private void writeTags(Writer writer, Map mapTags) throws IOException
{
if (!mapTags.isEmpty())
{
String sTags = mapTags.entrySet().stream()
.map(e -> '"' + e.getKey() + "\":\"" + e.getValue() + "\"")
.collect(Collectors.joining(","));
writer.write("\"tags\":{");
writer.write(sTags);
writer.write("},");
}
}
// ---- data members ------------------------------------------------
/**
* The flag specifying whether to include metric type and description
* into the output.
*/
private final boolean f_fExtended;
/**
* The list of metrics to write.
*/
private final List f_metrics;
}
// ----- inner interface: StreamSupplier --------------------------------
/**
* A supplier of {@link OutputStream} instances
*/
@FunctionalInterface
private interface StreamSupplier
{
/**
* Return the {@link OutputStream} to use to send a http response.
* @return the {@link OutputStream} to use to send a http response
* @throws IOException if there is an error creating the stream
*/
OutputStream get() throws IOException;
}
// ----- inner enum: Format ---------------------------------------------
/**
* An enum to represent the format to use for metric names and tag keys.
*/
public enum Format
{
/**
* Names will the default format without a scope, e.g. coherence_cluster_size
*/
Default,
/**
* Names will be a dot delimited without a scope, e.g. coherence.cluster.size
*/
DotDelimited,
/**
* Names will be underscore delimited with a scope, e.g. vendor:coherence_cluster_size
*/
Legacy,
/**
* Names will be MP 2.0 compatible with a scope, e.g. vendor_Coherence_Cluster_Size
*/
Microprofile,
}
// ----- constants ------------------------------------------------------
/**
* The System property to use to determine whether to always include
* extended information (type and/or description) when publishing metrics.
*/
private static final String PROP_EXTENDED = "coherence.metrics.extended";
/**
* A flag to determine whether to always include help information when
* publishing metrics.
*/
private static final boolean f_fAlwaysUseExtended
= Boolean.parseBoolean(System.getProperty(PROP_EXTENDED, "false"));
/**
* A system property that when true outputs metric names using Coherence legacy
* format.
*/
public static final String PROP_USE_LEGACY_NAMES = "coherence.metrics.legacy.names";
/**
* A system property that when true outputs metric names as Microprofile 2.0
* compatible metric names.
*/
public static final String PROP_USE_MP_NAMES = "coherence.metrics.mp.names";
/**
* A system property that when true outputs metric names as dot delimited metric names.
*/
public static final String PROP_USE_DOT_NAMES = "coherence.metrics.dot.names";
/**
* The "Accept" header value for the json media type.
*/
public static final String APPLICATION_JSON = "application/json";
/**
* The "Accept" header value for the text media type.
*/
public static final String TEXT_PLAIN = "text/plain";
/**
* The "Accept" header value for the wild-card media type.
*/
public static final String WILDCARD = "*/*";
/**
* An empty byte array to use as an empty response body.
*/
private static final byte[] EMPTY_BODY = new byte[0];
// ----- data members ---------------------------------------------------
/**
* The format to use for metric names and tag keys.
*/
private final Format f_format;
}