writeQuery() — netty Function Reference

Source Code

resolver-dns/src/main/java/io/netty/resolver/dns/DnsQueryContext.java lines 172–231

    final void writeQuery(boolean flush) {
        assert id == Integer.MIN_VALUE : this.getClass().getSimpleName() +
                ".writeQuery(...) can only be executed once.";

        if ((id = queryContextManager.add(nameServerAddr, this)) == -1) {
            // We did exhaust the id space, fail the query
            IllegalStateException e = new IllegalStateException("query ID space exhausted: " + question());
            finishFailure("failed to send a query via " + protocol(), e, false);
            queryLifecycleObserver.queryWritten(nameServerAddr, channel.newFailedFuture(e));
        }

        // Ensure we remove the id from the QueryContextManager once the query completes.
        promise.addListener((FutureListener<AddressedEnvelope<DnsResponse, InetSocketAddress>>) future -> {
            // Cancel the timeout task.
            Future<?> timeoutFuture = DnsQueryContext.this.timeoutFuture;
            if (timeoutFuture != null) {
                DnsQueryContext.this.timeoutFuture = null;
                timeoutFuture.cancel(false);
            }

            Throwable cause = future.cause();
            if (cause instanceof DnsNameResolverTimeoutException || cause instanceof CancellationException) {
                // This query was failed due a timeout or cancellation. Let's delay the removal of the id to reduce
                // the risk of reusing the same id again while the remote nameserver might send the response after
                // the timeout.
                channel.eventLoop().schedule(new Runnable() {
                    @Override
                    public void run() {
                        removeFromContextManager(nameServerAddr);
                    }
                }, ID_REUSE_ON_TIMEOUT_DELAY_MILLIS, TimeUnit.MILLISECONDS);
            } else {
                // Remove the id from the manager as soon as the query completes. This may be because of success,
                // failure or cancellation
                removeFromContextManager(nameServerAddr);
            }
        });
        final DnsQuestion question = question();
        final DnsQuery query = newQuery(id, nameServerAddr);

        query.setRecursionDesired(recursionDesired);

        query.addRecord(DnsSection.QUESTION, question);

        for (DnsRecord record: additionals) {
            query.addRecord(DnsSection.ADDITIONAL, record);
        }

        if (optResource != null) {
            query.addRecord(DnsSection.ADDITIONAL, optResource);
        }

        if (logger.isDebugEnabled()) {
            logger.debug("{} WRITE: {}, [{}: {}], {}",
                    channel, protocol(), id, nameServerAddr, question);
        }

        ChannelFuture f = sendQuery(query, flush);
        queryLifecycleObserver.queryWritten(nameServerAddr, f);
    }