Automate IBM MQ object creation with PCF in .NET using IKVM.NET

by | Dec 16, 2018 | BizTalk Community Blogs via Syndication | 0 comments

This post was originally published here

TL;DR – There is no decent .NET support for PCF in the IBM client, but we can use IKVM.NET to convert JARs to DLLs so we can still use .NET instead of JAVA to use PCF.

Intro

Programmable Command Formats (PCFs) define command and reply messages that can be used to create objects (Queues, Topics, Channels, Subscriptions,…) on IBM Websphere MQ. For my current project we wanted to build a custom REST API to automate object creation based on our custom needs. The IBM MQ REST API was not a possible alternative at that moment in time.

The problem

The .NET PCF namespaces are not supported/documented by IBM and do not provide the possibility to inquired the existing subscriptions on a queue manager. All other tasks we wanted to automate are possible in .NET. Using JAVA seemed to be the only alternative if we wanted to build this custom REST API with all features.

Action PCF Command Result Info
Create Local/Alias Queue MQCMD_CREATE_Q OK
Delete Queue MQCMD_DELETE_Q OK
List Queues MQCMD_INQUIRE_Q OK
Purge Queue MQCMD_CLEAR_Q OK
Create Subscription MQCMD_CREATE_SUBSCRIPTION OK
List Subscriptions MQCMD_INQUIRE_SUBSCRIPTION NOK Link1
  Link2
Delete Subscription MQCMD_DELETE_SUBSCRIPTION OK

Being able to use the .NET platform was a requirement at that time, because the whole build and deployment pipeline was focused on .NET.

IKVM.NET

After some searching I stumbled upon IKVM.NET:

“IKVM.NET is a JVM for the Microsoft .NET Framework and Mono. It can both dynamically run Java classes and can be used to convert Java jars into .NET assemblies. It also includes a port of the OpenJDK class libraries to .NET.“

Based on this description it sounded like it could offer a possible solution!

Using IKVM.NET we should be able to convert the IBM JARs to .NET assemblies and use the supported and documented IBM Java Packages from a .NET application.

From JAR to DLL

Now I will shortly explain how we were able to put it all together. Using IKVM.NET is not that easy when you use it for the first time. The whole process consists basically out of 3 steps:

  1. Download (and Install) the IBM MQ redistributable client (in order to extract the JAR files)
  2. Convert JARs to DLLs with IKVM.NET
  3. Copy DLLs and Reference in .NET project
    • The IBM Converted JARs and the IKVM.NET Runtime dlls

Convert JAR to DLL

Download IKVM: https://sourceforge.net/projects/ikvm/
Extract the IKVM files (c:toolsIKVM)
I have the IBM client installed, so the JAR files will be on there default installation (C:Program FilesIBMMQjavalib)

Open up a Command Prompt:

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set path=%path%;c:toolsIKVMbin
 
cd C:Program FilesIBMMQjavalib
 
ikvmc -target:library -sharedclassloader { com.ibm.mq.jar } { com.ibm.mq.jmqi.jar } { com.ibm.mq.headers.jar } { com.ibm.mq.pcf.jar }

You will find the output in the source directory of the JAR files:

Add References…

Now that we have our DLLs, we can add them to our .NET project. This seemed less easy then I thought, I spend a lot of time figuring out what dependencies I needed. In the end, this was my result:

1 = The IBM JARs converted to DLLs
2 = The IKVM.NET runtime DLLs

MqPcfAutomation Sample

To help you get started, I added my sample proof of concept solution to GitHub in the MqPcfAutomation repository.

In the sample a showcase the functionality described in the table at the beginning of this post.

Conclustion

In the end I am happy that I was able to build a solution for the problem. The question is if this approach is advised…
I don’t think IBM approves this approach, but it works for what we need it. We are using this solution now for more then 6 months without any issues. In the future we might be able to move to the IBM MQ REST API as more features will be added.

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