ServiceCall EIP
Available as of Camel 2.18
The serviceCall
EIP allows to call remote services in a distributed system. The service to call is looked up in a service registry of some sorts such as Kubernetes, Consul, etcd, Zookeeper. The EIP separates the configuration of the service registry from the calling of the service.
Maven users will need to add the dependency for the service registry supported from the following:
camel-consul
camel-etcd
camel-kubernetes
camel-ribbon
Each implementation has their own set of configuration.
Syntax
When calling a service you may just refer to the name of the service in the EIP as shown below:
from("direct:start") .serviceCall("foo") .to("mock:result");
And in XML DSL:
<camelContext xmlns="http://camel.apache.org/schema/spring"> <route> <from uri="direct:start"/> <serviceCall name="foo"/> <to uri="mock:result"/> </route> </camelContext>
Camel will then lookup a service with the name foo
from the chosen Camel component that integrates with the service registry. The lookup returns a set of IP:PORT
pairs that refer to a list of active servers that host the remote service. Camel will then select a server at random from the list to use and then build a Camel URI with the chosen IP and PORT number.
By default Camel uses the HTTP component, so the example above will resolve into a Camel URI that is called by a dynamic toD
endpoint as shown:
toD("http://IP:PORT") <toD uri="http:IP:port"/>
You can also call the service using URI parameters such as beer=yes
:
serviceCall("foo?beer=yes") <serviceCall name="foo?beer=yes"/>
You can also provide a context-path such as shown:
serviceCall("foo/beverage?beer=yes") <serviceCall name="foo/beverage?beer=yes"/>
Service Name to Camel URI Examples
So as you can see above the service name is resolved as a Camel endpoint URI, and here is a few more examples (where ->
shows the resolution of the Camel URI):
serviceCall("myService") -> http://hostname:port serviceCall("myService/foo") -> http://hostname:port/foo serviceCall("http:myService/foo") -> http:hostname:port/foo <serviceCall name="myService"/> -> http://hostname:port <serviceCall name="myService/foo"/> -> http://hostname:port/foo <serviceCall name="http:myService/foo"/> -> http:hostname:port/foo
If you want full control of the resolved URI you can provide an additional URI parameter where you specify the Camel URI as you want. In the URI you can use the service name which are then resolved to IP:PORT
as shown:
serviceCall("myService", "http:myService.host:myService.port/foo") -> http:hostname:port/foo serviceCall("myService", "netty4:tcp:myService?connectTimeout=1000") -> netty:tcp:hostname:port?connectTimeout=1000 <serviceCall name="myService" uri="http:myService.host:myService.port/foo"/> -> http:hostname:port/foo <serviceCall name="myService" uri="netty4:tcp:myService?connectTimeout=1000"/> -> netty:tcp:hostname:port?connectTimeout=1000
In the example above we want to call a service named myService
and we can control the resolved URI as in the second parameter. Notice how in the first example we can use serviceName.host
and serviceName.port
to refer to either the IP
or PORT
. If you just use serviceName
then it's resolved as IP:PORT
.
Configuring Service Call
By default Camel will call the service using the HTTP component, but you can configure to use a different component such as HTTP4, Netty4 HTTP as shown:
KubernetesConfigurationDefinition config = new KubernetesConfigurationDefinition(); config.setComponent("netty4-http"); // register the service call configuration context.setServiceCallConfiguration(config); from("direct:start") .serviceCall("foo") .to("mock:result");
In XML DSL:
<camelContext xmlns="http://camel.apache.org/schema/spring"> <kubernetesConfiguration id="kubernetes" component="netty4-http"/> <route> <from uri="direct:start"/> <serviceCall name="foo"/> <to uri="mock:result"/> </route> </camelContext>
Common Configuration
These are the common configuration that each implementation is sharing.
Name | Default | Description |
---|---|---|
| These properties are specific to what service call implementation are in use. For example if using ribbon, then the client properties are define in | |
|
| Sets the default Camel component to use for calling the remote service. By default the You can configure this to use |
| Sets a reference to a custom | |
| Sets a reference to a custom |
Kubernetes Configuration
Name | Default Value | Description | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
| Kubernetes API version when using | |||||||||
| Sets the Certificate Authority data when using | |||||||||
| Sets the Certificate Authority data that are loaded from the file when using | |||||||||
| Sets the Client Certificate data when using | |||||||||
| Sets the Client Certificate data that are loaded from the file when using | |||||||||
| Sets the Client Keystore algorithm, such as RSA when using | |||||||||
| Sets the Client Keystore data when using | |||||||||
| Sets the Client Keystore data that are loaded from the file when using | |||||||||
| Sets the Client Keystore passphrase when using | |||||||||
| Sets the DNS domain to use for | |||||||||
|
| The choice of strategy used to lookup the service. The list of lookup strategies are:
| ||||||||
| The URL for the Kubernetes master when using | |||||||||
| The Kubernetes namespace to use. By default the namespace's name is taken from the environment variable | |||||||||
| Sets the | |||||||||
| Sets the password for authentication when using | |||||||||
|
| Sets whether to turn on trust certificate check when using | ||||||||
| Sets the username for authentication when using |
Ribbon Configuration
Currently no ribbon specific options yet.
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