Saturday, August 31, 2019

OSGi Remote Services with Apache Dubbo

ECF's implementation of OSGi R7 Remote Services allows for replacing the underlying distribution system (repsonsible for the object serialization, transport, and other things). 

This makes it relatively easy to replace one kind of distribution (e.g. Jersey, ActiveMQ) with other/new distribution systems. 

Apache Dubbo has recently been contributed to Apache, and we've created a distribution provider based upon Apache Dubbo.

Here's a list of open ECF Remote Service distribution providers.   If you would like Remote Services support for a particular transport, or you've created your own distribution (or discovery) based upon some other transport and wish to make it available to others please let us know.


Wednesday, April 03, 2019

New Release: Python<->Java Remote Services

There is a new release (2.9.0) of the ECF distribution provider for OSGi R7 Remote Services between Java and Python.

This release has:

An upgraded version of Py4j
An upgraded version of Google Protocol Buffers
Enhancements to the distribution provider based upon the improved Py4j and Protobuf libs

In this previous blog posting there are links to tutorials and examples showing how to use remote services between Python<->Java.

Python<->Java remote services can be consumed or implemented in either Java or Python.

Monday, February 25, 2019

RESTful OSGi R7 Remote Services with Jersey 2.28 or Apache CXF 3.3

For some time, ECF has had remote service distribution providers that use the Jersey or the CXF implementation of standard Java API for RESTful Web Services (JaxRS). 

These distribution providers allow OSGi R7 Remote Services to be defined via JaxRS annotations and implemented by either Jersey 2.28 or CXF 3.3

OSGi R7 Remote Services provides support for renite service discovery, dynamics, versioning, configuration and extension of the distribution providers, and asynchronous remote calls as well as other features of the OSGi R7 Remote Services and Remote Service Admin specs.

This tutorial shows the use of OSGi Remote Services with these JaxRS distribution providers on Apache Karaf.

There is also a new version of the ECF Bndtools workspace template with example Bndtools projects showing the use of these distribution providers to define, configure, run and deploy RESTful OSGi R7 Remote Services with Bndtools 4.2+.

Sunday, November 04, 2018

ECF 3.14.4 released

ECF 3.14.4 was recently released.  This was a bug-fix release.  There are notes on some of the recent additions here.

Wednesday, August 22, 2018

OSGi Remote Services Between Python and Java

In a previous post, I described the support for OSGi Remote Services and Remote Service Admin in iPOPO 0.8.0 release.   The previous post refers to a tutorial showing a Python service impl and Python consumer.

Python<->Java Distribution Provider

Included with iPOPO 0.8.0 is a distribution provider that allows remote services between Java and Python frameworks.   For example, this is a tutorial, that uses Karaf on the Java side as the remote service implementation, and has a Python consumer that calls the Java-implemented remote service.

Python Service Implementation with Java Consumers

This distribution provider also supports Python-implemented remote services, with Java/OSGi consumers.   With iPOPO for dynamic service injection in Python, and Declarative Services for Java/OSGi, this allows very easy Python<->Java service-level interaction, with support for all dynamics, RSA management agent, extensible/customizable topology management, management of complicated service dependencies, pluggable local and network discovery, and other RS/RSA features handled consistently in both Java and Python.  As well, the use of OSGi-specified EndpointDescription service metadata allows service-level interoperability across languages.

Python<->Java with Protocol Buffers Serialization

Also included with this distribution provider is serialization using Google's protocol buffers.  This allows open, extensible, and efficient rpc between Python and Java.


Tuesday, August 21, 2018

Python for OSGi Remote Services

The iPOPO project is a Python implementation of key parts of a standard OSGi framework...e.g. bundles, the service registry and servicereference api, and a dynamic service injection framework similar to the Apache iPOJO project...thus the name iPOPO.

With the 0.8.0 release of iPOPO, there is now a Python implementation of the OSGi Remote Services and Remote Service Admin (RSA) specifications.   To distinguish from the previously-provided remote services in iPOPO, this is known as RSA Remote Services.

iPOPO's RSA Remote Services has many of the same advantages as Java-based Remote Services/RSA.  Some of these advantages:

Decoupling - name/service contract is decoupled from the implementation (and distribution)

Dynamics - The service registry dynamics behavior, along with all notifications, etc is available in Python

Injection and Service Dependency Management - iPOPO provides service injection and dependency management, built upon the Python API

Standard RemoteServiceAdmin Management Agent, RSA Console Commands

API for Distribution and Discovery Providers - There are documented APIs for creating new distribution and discovery providers, making it easy to support other transports and implementations for distribution (e.g. REST/JaxRS, Jsonrpc, MQTT, Zeroconf Discovery, etc).

Other advantages of Java-based OSGi services are described here.   All of these advantages apply to Python/iPOPO-based services, but Python can be used to implement and/or consume services.

Currently, there are two distribution providers included with iPOPO 0.8.0:  XmlRpc, Python-Java and one discovery provider: etcd.   See here for tutorials showing their usage with included sample remote services. 

Other distribution and discovery providers are being considered or worked on.  If you are interested in seeing a particular transport supported for distribution or discovery please open an issue on the iPOPO project.

Remote Services between Python and Java

The Python-Java distribution provider makes it possible to use OSGi Remote Services between Python and Java...on both sides.    This allows Remote Services to be exported from Python, and discovered/imported and consumed in Java, or exported from Java and discovered/imported/consumed from Python.  See here for a sample and tutorial.   These capabilities and the underlying distribution provider will be described in more detail in a subsequent posting.