io.questdb.cutlass.http.processors.PrometheusMetricsProcessor Maven / Gradle / Ivy

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 *  Copyright (c) 2014-2019 Appsicle
 *  Copyright (c) 2019-2022 QuestDB
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 *  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
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 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
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package io.questdb.cutlass.http.processors;

import io.questdb.cutlass.http.HttpChunkedResponseSocket;
import io.questdb.cutlass.http.HttpConnectionContext;
import io.questdb.cutlass.http.HttpRequestProcessor;
import io.questdb.metrics.Scrapable;
import io.questdb.network.PeerDisconnectedException;
import io.questdb.network.PeerIsSlowToReadException;

public class PrometheusMetricsProcessor implements HttpRequestProcessor {
    private static final CharSequence CONTENT_TYPE_TEXT = "text/plain; version=0.0.4; charset=utf-8";
    private final Scrapable metrics;

    public PrometheusMetricsProcessor(Scrapable metrics) {
        this.metrics = metrics;
    }

    @Override
    public void onRequestComplete(HttpConnectionContext context) throws PeerDisconnectedException, PeerIsSlowToReadException {
        HttpChunkedResponseSocket r = context.getChunkedResponseSocket();
        r.status(200, CONTENT_TYPE_TEXT);
        r.sendHeader();

        metrics.scrapeIntoPrometheus(r);

        r.done();
    }
}