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// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.container.handler;
import com.google.inject.Inject;
import com.yahoo.container.core.LogHandlerConfig;
import com.yahoo.container.jdisc.AsyncHttpResponse;
import com.yahoo.container.jdisc.ContentChannelOutputStream;
import com.yahoo.container.jdisc.HttpRequest;
import com.yahoo.container.jdisc.ThreadedHttpRequestHandler;
import com.yahoo.jdisc.handler.CompletionHandler;
import com.yahoo.jdisc.handler.ContentChannel;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.time.Instant;
import java.util.Optional;
import java.util.concurrent.Executor;
import java.util.concurrent.atomic.AtomicLong;
import java.util.logging.Level;
public class LogHandler extends ThreadedHttpRequestHandler {
private final LogReader logReader;
private static final long MB = 1024*1024;
@Inject
public LogHandler(Executor executor, LogHandlerConfig config) {
this(executor, new LogReader(config.logDirectory(), config.logPattern()));
}
LogHandler(Executor executor, LogReader logReader) {
super(executor);
this.logReader = logReader;
}
@Override
public AsyncHttpResponse handle(HttpRequest request) {
Instant from = Optional.ofNullable(request.getProperty("from"))
.map(Long::valueOf).map(Instant::ofEpochMilli).orElse(Instant.MIN);
Instant to = Optional.ofNullable(request.getProperty("to"))
.map(Long::valueOf).map(Instant::ofEpochMilli).orElse(Instant.MAX);
Optional<String> hostname = Optional.ofNullable(request.getProperty("hostname"));
return new AsyncHttpResponse(200) {
@Override
public void render(OutputStream output, ContentChannel networkChannel, CompletionHandler handler) {
try {
OutputStream blockingOutput = new MaxPendingContentChannelOutputStream(networkChannel, 1*MB);
logReader.writeLogs(blockingOutput, from, to, hostname);
blockingOutput.close();
}
catch (Throwable t) {
log.log(Level.WARNING, "Failed reading logs from " + from + " to " + to, t);
}
finally {
networkChannel.close(handler);
}
}
};
}
private static class MaxPendingContentChannelOutputStream extends ContentChannelOutputStream {
private final ContentChannel channel;
private final long maxPending;
private AtomicLong sent = new AtomicLong(0);
private AtomicLong acked = new AtomicLong(0);
public MaxPendingContentChannelOutputStream(ContentChannel endpoint, long maxPending) {
super(endpoint);
this.channel = endpoint;
this.maxPending = maxPending;
}
private long pendingBytes() {
return sent.get() - acked.get();
}
private class TrackCompletition implements CompletionHandler {
final long written;
TrackCompletition(long written) {
this.written = written;
sent.addAndGet(written);
}
@Override
public void completed() {
acked.addAndGet(written);
}
@Override
public void failed(Throwable t) {
acked.addAndGet(written);
}
}
@Override
public void send(ByteBuffer src) throws IOException {
try {
stallWhilePendingAbove(maxPending);
} catch (InterruptedException e) {}
send(src, new TrackCompletition(src.remaining()));
}
private void stallWhilePendingAbove(long pending) throws InterruptedException {
while (pendingBytes() > pending) {
Thread.sleep(1);
}
}
@Override
public void flush() throws IOException {
super.flush();
try {
stallWhilePendingAbove(0);
}
catch (InterruptedException e) {
throw new RuntimeException("Interrupted waiting for underlying IO to complete", e);
}
}
}
}
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