OPC UA Client

Since Camel 2.19

Both producer and consumer are supported

The Milo Client component provides access to OPC UA servers using the Eclipse Milo™ implementation.

Java 11+: This component requires Java 11+ 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>

URI format

The URI syntax of the endpoint is:

milo-client:opc.tcp://[user:password@]host:port/path/to/service?node=RAW(nsu=urn:foo:bar;s=item-1)

If the server does not use a path, then it is possible to simply omit it:

milo-client:opc.tcp://[user:password@]host:port?node=RAW(nsu=urn:foo:bar;s=item-1)

If no user credentials are provided the client will switch to anonymous mode.

All configuration options in the group client are applicable to the shared client instance. Endpoints will share client instances for each endpoint URI. So the first time a request for that endpoint URI is made, the options of the client group are applied. All further instances will be ignored.

If you need alternate options for the same endpoint URI it is possible though to set the clientId option which will by added internally to the endpoint URI in order to select a different shared connection instance. In other words, shared connections located by the combination of endpoint URI and client id.

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 Client component supports 25 options, which are listed below.

Name Description Default Type

clientId (common)

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

String

configuration (common)

All default options for client configurations.

MiloClientConfiguration

discoveryEndpointSuffix (common)

A suffix for endpoint URI when discovering.

String

discoveryEndpointUri (common)

An alternative discovery 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.

false

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.

false

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.

true

boolean

allowedSecurityPolicies (client)

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

String

applicationName (client)

The application name.

Apache Camel adapter for Eclipse Milo

String

applicationUri (client)

The application URI.

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

String

channelLifetime (client)

Channel lifetime in milliseconds.

Long

keyAlias (client)

The name of the key in the keystore file.

String

keyPassword (client)

The key password.

String

keyStorePassword (client)

The keystore password.

String

keyStoreType (client)

The key store type.

String

keyStoreUrl (client)

The URL where the key should be loaded from.

String

maxPendingPublishRequests (client)

The maximum number of pending publish requests.

Long

maxResponseMessageSize (client)

The maximum number of bytes a response message may have.

Long

miloClientConnectionManager (client)

Autowired Instance for managing client connections.

MiloClientConnectionManager

overrideHost (client)

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

false

boolean

productUri (client)

The product URI.

http://camel.apache.org/EclipseMilo

String

requestedPublishingInterval (client)

The requested publishing interval in milliseconds.

1_000.0

Double

requestTimeout (client)

Request timeout in milliseconds.

Long

sessionName (client)

Session name.

String

sessionTimeout (client)

Session timeout in milliseconds.

Long

Endpoint Options

The OPC UA Client endpoint is configured using URI syntax:

milo-client:endpointUri

with the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

endpointUri (common)

Required The OPC UA server endpoint.

String

Query Parameters (33 parameters)

Name Description Default Type

clientId (common)

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

String

dataChangeFilterDeadbandType (common)

Deadband type for MonitorFilterType DataChangeFilter.

0

UInteger

dataChangeFilterDeadbandValue (common)

Deadband value for MonitorFilterType DataChangeFilter.

0.0

Double

dataChangeFilterTrigger (common)

Daata change trigger for data change monitor filter type.

Enum values:

  • Status

  • StatusValue

  • StatusValueTimestamp

DataChangeTrigger

defaultAwaitWrites (common)

Default await setting for writes.

false

boolean

discoveryEndpointSuffix (common)

A suffix for endpoint URI when discovering.

String

discoveryEndpointUri (common)

An alternative discovery URI.

String

method (common)

The method definition (see Method ID).

String

monitorFilterType (common)

Monitor Filter Type for MonitoredItems.

Enum values:

  • dataChangeFilter

MonitorFilterType

node (common)

The node definition (see Node ID).

String

omitNullValues (common)

Omit notifications in case of null values.

true

boolean

samplingInterval (common)

The sampling interval in milliseconds.

0.0

Double

bridgeErrorHandler (consumer (advanced))

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

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 (advanced))

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

allowedSecurityPolicies (client)

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

String

applicationName (client)

The application name.

Apache Camel adapter for Eclipse Milo

String

applicationUri (client)

The application URI.

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

String

channelLifetime (client)

Channel lifetime in milliseconds.

Long

keyAlias (client)

The name of the key in the keystore file.

String

keyPassword (client)

The key password.

String

keyStorePassword (client)

The keystore password.

String

keyStoreType (client)

The key store type.

String

keyStoreUrl (client)

The URL where the key should be loaded from.

String

maxPendingPublishRequests (client)

The maximum number of pending publish requests.

Long

maxResponseMessageSize (client)

The maximum number of bytes a response message may have.

Long

overrideHost (client)

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

false

boolean

productUri (client)

The product URI.

http://camel.apache.org/EclipseMilo

String

requestedPublishingInterval (client)

The requested publishing interval in milliseconds.

1_000.0

Double

requestTimeout (client)

Request timeout in milliseconds.

Long

sessionName (client)

Session name.

String

sessionTimeout (client)

Session timeout in milliseconds.

Long

Message Headers

The OPC UA Client component supports 2 message header(s), which is/are listed below:

Name Description Default Type

CamelMiloNodeIds (producer)

Constant: HEADER_NODE_IDS

The node ids.

List

await (producer)

Constant: HEADER_AWAIT

The await setting for writes.

Boolean

Discovery

If the server uses a dedicated discovery endpoint (e.g. /discovery), which may support different (less secure) security policies, then you can make use of this via the parameter discoveryEndpointSuffix, which will be appended to the endpointUri. Or by using an explicit discoveryEndpointUri.

Overriding the host name

The client uses the host information from the endpoint information, queried from the server. However in some situations this endpoint URI might be different, and wrong from the point of view of the connecting client (e.g. an internal hostname).

In this case it is possible to set the parameter overrideHost to true, which will take the discovered endpoint information, but override the host information with the value of the original URI.

Node ID

In order to define a target node a namespace and node id is required. In previous versions this was possible by specifying nodeId and either namespaceUri or namespaceIndex. However this only allowed for using string based node IDs. And while this configuration is still possible, the newer one is preferred.

The new approach is to specify a full namespace+node ID in the format ns=1;i=1 which also allows to use the other node ID formats (like numeric, GUID/UUID or opaque). If the node parameter is used the older ones must not be used. The syntax of this node format is a set of key=value pairs delimited by a semi-colon (;).

Exactly one namespace and one node id key must be used. See the following table for possible keys:

Key Type Description

ns

namespace

Numeric namespace index

nsu

namespace

Namespace URI

s

node

String node ID

i

node

Numeric node ID

g

node

GUID/UUID node ID

b

node

Base64 encoded string for opaque node ID

As the values generated by the syntax cannot be transparently encoded into a URI parameter value, it is necessary to escape them. However Camel allows to wrap the actual value inside RAW(…), which makes escaping unnecessary. For example:

milo-client:opc.tcp://user:password@localhost:12345?node=RAW(nsu=http://foo.bar;s=foo/bar)

Method ID

It is possible to perform methods calls on OPC UA nodes. If the parameter method is set to the Node ID of a method call (the node ID must be set to the parent object in this case), then a method call will be performed instead of a write operation.

Input parameters are taken from the body:

  • If the body is null, then an empty Variant[] will be used

  • If the body is a Variant[], then it will be used as is

  • If the body is a Variant, then it will be wrapped in a Variant[] array

  • Otherwise the body will be converted into a Variant and wrapped in an array of Variant[]

Read Values from Nodes

The component provide a producer to read values from multiple opc-ua nodes. The Node-IDs will be defined in the header CamelMiloNodeIds as list of strings. (see Node-ID for the ID format).

Example:

from("direct:start")
    .setHeader("CamelMiloNodeIds", constant(Arrays.asList("nsu=urn:org:apache:camel;s=myitem1")))
    .setHeader("await", constant(true)) // await: parameter "defaultAwaitWrites"
        .enrich("milo-client:opc.tcp://localhost:4334", new AggregationStrategy() {

            @Override
            public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
                return newExchange;
            }
        }).to("mock:test1");

Security policies

When setting the allowing security policies is it possible to use the well known OPC UA URIs (e.g. http://opcfoundation.org/UA/SecurityPolicy#Basic128Rsa15) or to use the Milo enum literals (e.g. None). Specifying an unknown security policy URI or enum is an error.

The known security policy URIs and enum literals are can be seen here: SecurityPolicy.java

In any case security policies are considered case sensitive.

Spring Boot Auto-Configuration

When using milo-client 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 72 options, which are listed below.

Name Description Default Type

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

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

String

camel.component.milo-browse.application-name

The application name.

Apache Camel adapter for Eclipse Milo

String

camel.component.milo-browse.application-uri

The application URI.

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

String

camel.component.milo-browse.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-browse.channel-lifetime

Channel lifetime in milliseconds.

Long

camel.component.milo-browse.client-id

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

String

camel.component.milo-browse.configuration

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

MiloClientConfiguration

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

A suffix for endpoint URI when discovering.

String

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

An alternative discovery URI.

String

camel.component.milo-browse.enabled

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

Boolean

camel.component.milo-browse.key-alias

The name of the key in the keystore file.

String

camel.component.milo-browse.key-password

The key password.

String

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

The keystore password.

String

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

The key store type.

String

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

The URL where the key should be loaded from.

String

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

The maximum number of pending publish requests.

Long

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

The maximum number of bytes a response message may have.

Long

camel.component.milo-browse.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-browse.override-host

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

false

Boolean

camel.component.milo-browse.product-uri

The product URI.

http://camel.apache.org/EclipseMilo

String

camel.component.milo-browse.request-timeout

Request timeout in milliseconds.

Long

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

The requested publishing interval in milliseconds.

Double

camel.component.milo-browse.session-name

Session name.

String

camel.component.milo-browse.session-timeout

Session timeout in milliseconds.

Long

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.server.security.ServerCertificateValidator type.

ServerCertificateValidator

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
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