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Available as of Camel 2.18
The 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, zookeeperZookeeper.
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.
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When calling a service you may just refer to the name of the service in the EIP as shown below:
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from("direct:start") .serviceCall("foo") .to("mock:result"); |
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Camel will then lookup a service with the name "name foo
" from the chosen Camel component that integrates with the service registry. The lookup returns a set of of IP:PORT
paris pairs that refer to which a list of active servers that host the remote service. Camel will then pick select a server at random server from the list to use and then build a Camel uri 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 URI that is called by a dynamic to dynamic toD
endpoint as shown:
Code Block |
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toD("http://IP:PORT") <toD uri="http:IP:port"/> |
You can also call the service using URI parameters such as beer=yes
:
Code Block |
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serviceCall("foo?beer=yes") <serviceCall name="foo?beer=yes")/> |
You can also provide a context-path such as shown:
Code Block |
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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 uriURI, and here is a few more examples (where where ->
shows what the resolution of the Camel uri is resolved asURI):
Code Block |
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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 URI parameter where you specify the Camel uri URI as you want. In the uri URI you can use the service name which are then resolved to to IP:PORT
as shown:
Code Block |
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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 "named myService
" and we can control the resolved URI as in the 2nd second parameter. Notice how in the 1st first example we can use use serviceName.host
and and serviceName.port
to refer to either the the IP
or PORT
. If you just use use serviceName
then its 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:
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KubernetesConfigurationDefinition config = new KubernetesConfigurationDefinition(); config.setComponent("netty4-http"); // register the service call configuration context.setServiceCallConfiguration(config); from("direct:start") .serviceCall("foo") .to("mock:result"); |
.. and in In XML DSL:
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<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>
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Common Configuration
These are the common configuration that each implementation is sharing.
Name | Default | Description | |||
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| 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. You can configure this to use | |||
| Sets a reference to a customcustom | ||||
| Sets a reference to a customcustom | clientProperty | These properties are specific to what service call implementation are in use. For example if using ribbon, then the client properties are define in com.netflix.client.config.CommonClientConfigKey . |
Kubernetes Configuration
Name | Default Value | Description | lookupenvironment | What strategy to lookup the service. Possible values: environment, dns, client. By default enviornment is used to use environment variables. dns is for using DNS domain names. client is for use Java Client to call the kubernetes master API and query which servers are active hosting the service. | ||||||
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dnsDomain | Sets the DNS domain to use for DNS lookup. | |||||||||
namespace | The kubernetes namespace to use. Will by default use namespace from the ENV variable KUBERNETES_MASTER. | |||||||||
| Client lookup. | Kubernetes API version | .||||||||
masterUrl | Client lookup. The url for the Kubernets master. | |||||||||
username | Sets the username for authentication when using client lookup | |||||||||
password | Sets the password for authentication when using client lookup | |||||||||
oauthToken | Sets the OAUTH token for authentication (instead of username/password) when using client lookup | when using | ||||||||
| Sets the Certificate Authority data when | using using | ||||||||
| Sets the Certificate Authority data that are loaded from the file when | using using | ||||||||
| Sets the Client Certificate data when | using using | ||||||||
| Sets the Client Certificate data that are loaded from the file when | using using | ||||||||
| Sets the Client Keystore algorithm, such as RSA when | using using | ||||||||
| Sets the Client Keystore data when | using using | ||||||||
| Sets the Client Keystore data that are loaded from the file when | using using | ||||||||
| Sets the Client Keystore passphrase | when using client lookupwhen 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 | |||||||||
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| Sets whether to turn on trust certificate check when usingusing | ||||||||
| Sets the username for authentication when using |
Ribbon Configuration
Currenly Currently no ribbon specific options yet.