Reactor Netty Documentation

This module provides tracing decorators for HttpClient and HttpServer using Brave.

DEPRECATION NOTICE: This module is DEPRECATED as of Reactor Netty 1.1.0 and will be removed in Reactor Netty 2.0.0. It is recommended to use the standard HttpClient/HttpServer integration with Micrometer Tracing instead.

By default, TcpClient.create() uses a shared ConnectionProvider that implements a "fixed" connection pool per remote host (hostname + port).

Default Limits:

• maxConnections: 500 active channels.
• pendingAcquireMaxCount: 1000 pending channel acquisition attempts.

Important Behavior: Unlike HttpClient, connections used by TcpClient are never returned to the pool; they are closed after use. When a connection is closed, its slot in the pool is freed, allowing a new connection to be opened. This ensures protocol compatibility is managed by the user/framework.

Reactor Netty requires Java 8 or higher. It has the following transitive dependencies:

• Reactive Streams v1.0.4
• Reactor Core v3.x
• Netty v4.2.x

To use Highlight.js on a web page, include the library and a CSS theme, then call hljs.initHighlightingOnLoad(). The library will automatically find and highlight code inside <pre><code> tags by attempting to auto-detect the language.

To explicitly specify a language when auto-detection fails, use the class attribute on the <code> tag with the language name (e.g., class="html") or use the language- or lang- prefixes.

To disable highlighting for a specific block, use the nohighlight class.

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If automatic detection fails, you can manually specify the language using the class attribute on the <code> tag with the format language-{lang} or lang-{lang} (e.g., class="html").

To prevent a specific block from being highlighted, use the nohighlight class.

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To prevent large code blocks from freezing the browser UI, you can offload the highlighting process to a Web Worker.

1. In the main script, capture the code content and post it to the worker.
2. In the worker script, import the highlight.js library and use self.hljs.highlightAuto(data) to process the code, then post the result back.

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The documentation is written in Asciidoc using Antora. You can contribute improvements via pull requests.

To verify your changes locally, it is recommended to use the asciidoctor Gradle task to generate the documentation, as some sections rely on included files that may not render completely on GitHub.

The TCP server integrates with Micrometer. Metrics are prefixed with reactor.netty.tcp.server.

Available metrics:

• reactor.netty.tcp.server.connections.total (Gauge): Total opened connections.
• reactor.netty.tcp.server.data.received (DistributionSummary): Bytes received.
• reactor.netty.tcp.server.data.sent (DistributionSummary): Bytes sent.
• reactor.netty.tcp.server.errors (Counter): Number of errors.
• reactor.netty.tcp.server.tls.handshake.time (Timer): TLS handshake duration.

To enable built-in integration:

TcpServer.create()
    .metrics(true)
    .bind()
    .get()
    .onDispose()
    .block();

To prevent resource leaks, you must dispose of connection pools when they are no longer needed.

• If using default ConnectionProvider: Use HttpResources#disposeLoopsAndConnections() or HttpResources#disposeLoopsAndConnectionsLater().
• If using custom ConnectionProvider: Use ConnectionProvider#dispose(), ConnectionProvider#disposeLater(), or ConnectionProvider#disposeWhen().

Warning: Disposing a resource makes it unavailable for all clients currently using it.

By default, HttpServer resources (event loop groups, native transport, and security libraries like OpenSsl) are initialized on demand during the bind operation. To avoid latency during the first request, you can use the .warmup() method to preload these resources.

HttpServer.create()
    .warmup()
    .handle((request, response) -> response.sendString(Mono.just("Hello World!")))
    .bindNow();