OPC UA Server

Since Camel 2.19

Both producer and consumer are supported

The Milo Server component provides an OPC UA server using the Eclipse Milo™ implementation.

Java 9+: This component requires Java 9+ at runtime.

Maven users will need to add the following dependency to their pom.xml for this component:

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-milo</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

Messages sent to the endpoint from Camel will be available from the OPC UA server to OPC UA Clients. Value write requests from OPC UA Client will trigger messages which are sent into Apache Camel.

URI format

milo-server:itemId[?options]

Configuring Options

Camel components are configured on two separate levels:

  • component level

  • endpoint level

Configuring Component Options

The component level is the highest level which holds general and common configurations that are inherited by the endpoints. For example a component may have security settings, credentials for authentication, urls for network connection and so forth.

Some components only have a few options, and others may have many. Because components typically have pre configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.

Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.

Configuring Endpoint Options

Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for both.

Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL as a type safe way of configuring endpoints.

A good practice when configuring options is to use Property Placeholders, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.

The following two sections lists all the options, firstly for the component followed by the endpoint.

Component Options

The OPC UA Server component supports 20 options, which are listed below.

Name Description Default Type

applicationName (common)

The application name.

String

applicationUri (common)

The application URI.

String

bindAddresses (common)

Set the addresses of the local addresses the server should bind to.

String

buildInfo (common)

Server build info.

BuildInfo

namespaceUri (common)

The URI of the namespace, defaults to urn:org:apache:camel.

String

path (common)

The path to be appended to the end of the endpoint url. (doesn’t need to start with '/').

String

port (common)

The TCP port the server binds to.

int

productUri (common)

The product URI.

String

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

boolean

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

boolean

autowiredEnabled (advanced)

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

boolean

certificate (security)

Server certificate.

X509Certificate

certificateManager (security)

Server certificate manager.

CertificateManager

certificateValidator (security)

Validator for client certificates.

CertificateValidator

defaultCertificateValidator (security)

Validator for client certificates using default file based approach.

String

enableAnonymousAuthentication (security)

Enable anonymous authentication, disabled by default.

boolean

securityPolicies (security)

Security policies.

Set

securityPoliciesById (security)

Security policies by URI or name. Multiple policies can be separated by comma.

String

userAuthenticationCredentials (security)

Set user password combinations in the form of user1:pwd1,user2:pwd2 Usernames and passwords will be URL decoded.

String

usernameSecurityPolicyUri (security)

Set the UserTokenPolicy used when.

Enum values:

  • None

  • Basic128Rsa15

  • Basic256

  • Basic256Sha256

  • Aes128_Sha256_RsaOaep

  • Aes256_Sha256_RsaPss

SecurityPolicy

Endpoint Options

The OPC UA Server endpoint is configured using URI syntax:

milo-server:itemId

with the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

itemId (common)

Required ID of the item.

String

Query Parameters (4 parameters)

Name Description Default Type

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

boolean

exceptionHandler (consumer (advanced))

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

ExceptionHandler

exchangePattern (consumer (advanced))

Sets the exchange pattern when the consumer creates an exchange.

Enum values:

  • InOnly

  • InOut

  • InOptionalOut

ExchangePattern

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

boolean

Spring Boot Auto-Configuration

When using milo-server with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-milo-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 47 options, which are listed below.

Name Description Default Type

camel.component.milo-client.allowed-security-policies

A set of allowed security policy URIs. Default is to accept all and use the highest.

String

camel.component.milo-client.application-name

The application name.

Apache Camel adapter for Eclipse Milo

String

camel.component.milo-client.application-uri

The application URI.

http://camel.apache.org/EclipseMilo/Client

String

camel.component.milo-client.autowired-enabled

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

Boolean

camel.component.milo-client.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

camel.component.milo-client.channel-lifetime

Channel lifetime in milliseconds.

Long

camel.component.milo-client.client-id

A virtual client id to force the creation of a new connection instance.

String

camel.component.milo-client.configuration

All default options for client configurations. The option is a org.apache.camel.component.milo.client.MiloClientConfiguration type.

MiloClientConfiguration

camel.component.milo-client.discovery-endpoint-suffix

A suffix for endpoint URI when discovering.

String

camel.component.milo-client.discovery-endpoint-uri

An alternative discovery URI.

String

camel.component.milo-client.enabled

Whether to enable auto configuration of the milo-client component. This is enabled by default.

Boolean

camel.component.milo-client.key-alias

The name of the key in the keystore file.

String

camel.component.milo-client.key-password

The key password.

String

camel.component.milo-client.key-store-password

The keystore password.

String

camel.component.milo-client.key-store-type

The key store type.

String

camel.component.milo-client.key-store-url

The URL where the key should be loaded from.

String

camel.component.milo-client.lazy-start-producer

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

Boolean

camel.component.milo-client.max-pending-publish-requests

The maximum number of pending publish requests.

Long

camel.component.milo-client.max-response-message-size

The maximum number of bytes a response message may have.

Long

camel.component.milo-client.milo-client-connection-manager

Instance for managing client connections. The option is a org.apache.camel.component.milo.client.MiloClientConnectionManager type.

MiloClientConnectionManager

camel.component.milo-client.override-host

Override the server reported endpoint host with the host from the endpoint URI.

false

Boolean

camel.component.milo-client.product-uri

The product URI.

http://camel.apache.org/EclipseMilo

String

camel.component.milo-client.request-timeout

Request timeout in milliseconds.

Long

camel.component.milo-client.requested-publishing-interval

The requested publishing interval in milliseconds.

Double

camel.component.milo-client.session-name

Session name.

String

camel.component.milo-client.session-timeout

Session timeout in milliseconds.

Long

camel.component.milo-server.application-name

The application name.

String

camel.component.milo-server.application-uri

The application URI.

String

camel.component.milo-server.autowired-enabled

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

Boolean

camel.component.milo-server.bind-addresses

Set the addresses of the local addresses the server should bind to.

String

camel.component.milo-server.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

camel.component.milo-server.build-info

Server build info. The option is a org.eclipse.milo.opcua.stack.core.types.structured.BuildInfo type.

BuildInfo

camel.component.milo-server.certificate

Server certificate. The option is a java.security.cert.X509Certificate type.

X509Certificate

camel.component.milo-server.certificate-manager

Server certificate manager. The option is a org.eclipse.milo.opcua.stack.core.security.CertificateManager type.

CertificateManager

camel.component.milo-server.certificate-validator

Validator for client certificates. The option is a org.eclipse.milo.opcua.stack.core.security.CertificateValidator type.

CertificateValidator

camel.component.milo-server.default-certificate-validator

Validator for client certificates using default file based approach.

String

camel.component.milo-server.enable-anonymous-authentication

Enable anonymous authentication, disabled by default.

false

Boolean

camel.component.milo-server.enabled

Whether to enable auto configuration of the milo-server component. This is enabled by default.

Boolean

camel.component.milo-server.lazy-start-producer

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

Boolean

camel.component.milo-server.namespace-uri

The URI of the namespace, defaults to urn:org:apache:camel.

urn:org:apache:camel

String

camel.component.milo-server.path

The path to be appended to the end of the endpoint url. (doesn’t need to start with '/').

String

camel.component.milo-server.port

The TCP port the server binds to.

Integer

camel.component.milo-server.product-uri

The product URI.

String

camel.component.milo-server.security-policies

Security policies.

Set

camel.component.milo-server.security-policies-by-id

Security policies by URI or name. Multiple policies can be separated by comma.

String

camel.component.milo-server.user-authentication-credentials

Set user password combinations in the form of user1:pwd1,user2:pwd2 Usernames and passwords will be URL decoded.

String

camel.component.milo-server.username-security-policy-uri

Set the UserTokenPolicy used when.

SecurityPolicy