OSGi duplicate package export: sdk-core vs. sdk-server

[JulianSchuette]

Hello!

Both bundles sdk-server and sdk-core have
Export-Package: ... org.eclipse.milo.opcua.sdk.core, ...
in their OSGi headers, which leads to the following error when starting sdk-server in Karaf/Felix:

Error executing command: Error executing command on bundles:
    Error starting bundle 253: Uses constraint violation. Unable to resolve resource org.eclipse.milo.sdk-server [org.eclipse.milo.sdk-server [253](R 253.0)] because it exports package 'org.eclipse.milo.opcua.sdk.core' and is also exposed to it from resource org.eclipse.milo.sdk-core [org.eclipse.milo.sdk-core [278](R 278.0)] via the following dependency chain:

  org.eclipse.milo.sdk-server [org.eclipse.milo.sdk-server [253](R 253.0)]
    import: (&(osgi.wiring.package=org.eclipse.milo.opcua.sdk.core.model)(version>=0.1.0)(!(version>=1.0.0)))
     |
    export: osgi.wiring.package: org.eclipse.milo.opcua.sdk.core.model; uses:=org.eclipse.milo.opcua.sdk.core
    export: osgi.wiring.package=org.eclipse.milo.opcua.sdk.core
  org.eclipse.milo.sdk-core [org.eclipse.milo.sdk-core [278](R 278.0)] Unresolved requirements: [[org.eclipse.milo.sdk-server [253](R 253.0)] osgi.wiring.package; (&(osgi.wiring.package=org.eclipse.milo.opcua.sdk.core.model)(version>=0.1.0)(!(version>=1.0.0)))]

Looks like either that package import should be removed from sdk-server or sdk-server should be declared as a fragment bundle of sdk-core?

[kevinherron]

I don't know enough about OSGi to know what the correct fix is. Can you try removing it from the sdk-server project and see if everything still works for you?

[ctron]

I also just looked a bit into it. It seems that milo does also import "sun.misc", although that seems never to be used? Or did I just miss it?

[kevinherron]

I don't see "sun.misc" used anywhere either. I suspect it was once used for something like generating certificates, but I don't see it appearing anywhere now...

[ctron]

Ok ... there also is sun.nio.ch .. which seems to be unused.

But I do spot a reference to sun.security .. maybe have a look.

The other two could be removed?!

[ctron]

I made a PR #60 for the two packages.

[kevinherron]

@JulianSchuette this should be fixed in master now... if you have a chance give it a try and let us know.

[ctron]

@JulianSchuette I also did update the camel Milo repository. The layout is a bit different now, but you can create a Karat feature and archive now. Just do a local build of Milo first.

[JulianSchuette]

Thank you guys! I can install and run the camel-milo feature (which pulls in the milo feature) in Karaf. However, when testing the following route, there is a CNF exception.
I guess the reason is that both bundles, sdk-core and sdk-server export the same package org.eclipse.milo.opcua.core. OSGi resolves packages only to exactly one bundle - in this case it's sdk-core, but the missing class NamespaceTable is contained in sdk-server. Exporting a package from several bundles is not a good idea in most cases and should be refactored, but I do not want to mess with your code or might be completey wrong here. There are ways to force OSGi to ignore the problem using Require-Bundle, but that would be a hack.

Would it be possible to move classes in org.eclipse.milo.opcua.sdk.core to bundle sdk-core?

Camel route using milo:

<?xml version="1.0" encoding="UTF-8"?>
<blueprint
    xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="
      http://www.osgi.org/xmlns/blueprint/v1.0.0
      http://www.osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd">

    <camelContext xmlns="http://camel.apache.org/schema/blueprint">
      <route id="testroute">
        <from uri="paho:javaonedemo/eclipse-greenhouse-9home/sensors/temperature?brokerUrl=tcp://iot.eclipse.org:1883"/>
        <log message="Temp ${body}"/>
        <convertBodyTo type="java.lang.String"/>
        <to uri="milo-server:MyItem"/>
      </route>
    </camelContext>
</blueprint>

CNFException:

java.lang.NoClassDefFoundError: org/eclipse/milo/opcua/sdk/core/NamespaceTable
    at org.eclipse.milo.opcua.sdk.server.NamespaceManager.<init>(NamespaceManager.java:45)
    at org.eclipse.milo.opcua.sdk.server.OpcUaServer.<init>(OpcUaServer.java:89)
    at org.apache.camel.component.milo.server.MiloServerComponent.doStart(MiloServerComponent.java:136)
    at org.apache.camel.support.ServiceSupport.start(ServiceSupport.java:61)
    at org.apache.camel.impl.DefaultCamelContext.startService(DefaultCamelContext.java:3371)
    at org.apache.camel.impl.DefaultCamelContext.initComponent(DefaultCamelContext.java:431)
    at org.apache.camel.impl.DefaultCamelContext.lambda$getComponent$9(DefaultCamelContext.java:411)

Package org.eclipse.milo.opcua.core is exported twice:

karaf@root()> package:exports -d
Package Name                             | Version | Exporting bundles (ID)
---------------------------------------------------------------------------
org.eclipse.milo.opcua.sdk.core          | 0.1.0   | 243 244
karaf@root()> la
START LEVEL 100 , List Threshold: 0
 ID | State     | Lvl | Version                            | Name
[...]
243 | Active    |  80 | 0.1.0.SNAPSHOT                     | sdk-core
244 | Active    |  80 | 0.1.0.SNAPSHOT                     | sdk-server
[...]

[ctron]

@JulianSchuette You are always one step ahead of what I am trying to do 😉

I will look into this. But I fully agree. Different artifacts should not export different bundles.

[ctron]

I am going to track this in a separate issue.