Configuring the Netty Runtime
This section is for configuring the Netty runtime used for the CXF standalone model. The Netty runtime is used by HTTP servers and HTTP clients using a decoupled endpoint. The Netty runtime's thread pool, connector and timeouts can be configured. You can also set a number of the security settings for an HTTP service provider through the Netty runtime.
The elements used to configure the Netty runtime are defined in the namespace
http://cxf.apache.org/transports/http-netty-server/configuration. It is commonly referred to using the prefix
httpn. In order to use the Betty configuration elements you will need to add the lines shown below to the
beans element of your endpoint's configuration file. In addition, you will need to add the configuration elements' namespace to the
httpn:engine-factory element is the root element used to configure the Netty runtime used by an application. It has a single required attribute, bus, whose value is the name of the Bus that manages the Netty instances being configured.
The value is typically cxf which is the name of the default Bus instance.
httpn:engine-factory element has three children that contain the information used to configure the HTTP ports instantiated by the Netty runtime factory. The children are described below.
Specifies the configuration for a particular Netty runtime instance.
Specifies a reusable set of properties for securing an HTTP server. It has a single attribute,
Specifies a reusable set of properties for controlling a Netty instance's thread pool. It has a single attribute,
httpn:engine element is used to configure specific instances of the Netty runtime. It has a single attribute,
port, that specifies the number of the port being managed by the Netty instance.
You can specify a value of 0 for the port attribute. Any threading properties specified in an
httpn:engine element with its port attribute set to 0 are used as the configuration for all Netty listeners that are not explicitly configured.
httpn:engine element can have two children: one for configuring security properties and one for configuring the Netty instance's thread pool. For each type of configuration you can either directly provide the configuration information or provide a reference to a set of configuration properties defined in the parent
The child elements used to provide the configuration properties are described below.
Specifies a set of properties for configuring the security used for the specific Netty instance. See the TLS Configuration page for more information.
Refers to a set of security properties defined by a
Specifies the size of the thread pool used by the specific Netty instance.
Refers to a set of properties defined by a
If the value is true , the Netty Engine will set up a session manager for the Netty server engine to maintain the sessions. The default value of it is false.
The the value is true, the Netty Engine connector's socket will enable the SO_REUSEADDR flage. The default value of it is true.
Configuring the thread pool
You can configure the size of a Netty instance's thread pool by either:
- Specifying the size of thread pool using a
identifiedThreadingParameterselement in the
engine-factoryelement. You then refer to the element using a
Specify the size of the of thread pool directly using a
threadingParametershas one attribute to specify the size of a thread pool. The attribute is described below.
httpn:identifiedThreadingParameterselement has a single child
Specifies the number of threads available to the Netty instance for processing requests.
If HttpServerEngineSupport#ENABLE_HTTP2 bus property is set, Netty engine will enable the HTTP/2 support as well: HTTP/2 over cleartext (h2c) if TLS is not configured, regular HTTP/2 otherwise. It requires additional dependencies to be bundled by the application.
Please be aware that if you configure HTTP/2 + TLS, CXF right now only supports JDK SSL provider.
The example below shows a configuration fragment that configures a Netty instance on port number 9001.