Presidents Meeting and German Natural User Group – Legacy Coder Podcast #4

Presidents Meeting and German Natural User Group

Let’s talk about what was presented and discussed at Software AG’s User Group Presidents Meeting and the German Natural User Group in Darmstadt in November 2017 in episode four of the Legacy Coder Podcast.

User Group Presidents Meeting

  • What’s the point of the meeting?
    Welcome to the International User Groups Presidents Meeting

    • Planning the International User Groups Conference (topics, date, venue etc.).
  • What was presented by Software AG?
    • Software AG’s revenue is now > 1 Billion. 4,400 employees all over the world. Ca. 25% Adabas/Natural.
    • 70% of the largest 1,000 companies worldwide use Software AG products.
    • ADAMOS: Joint Venture with big machine builders like Zeiss and Dürr.
    • Don’t rip and replace! Modernize!
    • 3 big moves: Adabas/Natural, integration with webMethods, IoT (1 bn. investment).
    • Modern architecture: System of Records, Integration, IoT/AI.
    • Software AG named by Gartner as leader in Streaming Analytics, InMemory Databases.
  • What was discussed with regards to Adabas/Natural?
    • Don’t separate Adabas and Natural. There will be only one conference for both technologies with a single keynote.
    • Max. 30min presentations, time restrictions for information about business, platform, environment.
    • Natuaral customer base: Mainframe vs. LUW: 50%/50%
    • A workshop for Natural developers would be interesting (best practices, architecture, training).
    • A Hackathon will not be possible at IUGC.
    • How to find/meet other customers with similar problems?
  • Topics for IUGC 2018 in Berlin
    • Already 5-6 presentations submitted.
    • NaturalONE (new features, introducing the IDE etc.)
    • DevOps (CI, Docker, etc.)
    • Rehosting (Mainframe -> LUW)
    • Who uses or plans to use Cloud Computing?
    • 2050 readiness award
  • International User Group Conference 2018 in Berlin
    Members of Software AG's International User Groups

    • Registration is open!

German Natural User Group

  • Ca. 60 attendees from all over Germany.
    About 60 Natural Developers get together for the German Natural User Group in November 2017 in Darmstadt
  • Quite a few “young” Natural developers were present. The “Generational Change” starts…
    Young Natural Developers at the German Natural User Group in Darmstadt in November 2017
  • I’m the new speaker of the German Natural User Group.
    Stefan Macke is the new speaker of the German Natural User Group
  • Topics of the talks
    • zIIP enablement for Adabas/Natural
    • New features of EntireX
    • How to develop your own Eclipse plugins for NaturalONE
      How to develop your own Eclipse plugin for NaturalONE

    • New features in Natural und NaturalONE
      Code Coverage in NaturalONE

      • Natural editor will be shut down with release in fall of 2018. There are still many customers that have concerns.
    • Adabas and Natural in a Docker container, started via Alexa
      Adabas now runs in a Docker container
    • Visualizing Adabas Events with ElasticSearch and Kibana
      Adabas pushes events to ElasticSearch that can be visualized with Kibana
    • RealHtml4Natural – an alternative webframework for Natural build on top of the Natural Native Interfaces and distributed under the GPL-3.0 license.

Call to Action

Start Tweeting with #AdabasNatural2050 and #IUGC18!

Links

Modern Natural Development with NaturalONE – Legacy Coder Podcast #3

Modern Natural Development with NaturalONE

Why would anyone dismiss the good old Natural editor and switch over to NaturalONE? Let’s find out what features NaturalONE has to offer in the third episode of the Legacy Coder Podcast.

Why should you switch over to NaturalONE?

  • Increased developer productivity
    • Use Copy and Paste (duh!) for high quality Natural programming 😉
    • Syntax Highlighting will help you understand the source code faster.
    • Make use of intelligent search and replace features with regular expressions.
    • Code Completion makes you type way less than before.
      Code Completion in NaturalONE
    • Code Navigation (jump to a variable definition etc.) lets you explore the code base with a few keystrokes.
    • You can use Code Folding for focussing on the really important stuff.
    • Multiple compile errors are displayed instantly without uploading the source to the server.
      Multiple compile errors in NaturalONE
  • Repository based development
    • Finally develop software like the cool kids do!
    • Every code change is documented and can be rolled back with just a few commands. It can even be attached to an issue tracker like Jira or Redmine.
      Git integration in NaturalONE
    • You can try out new things in an isolated environment.
    • You can automate your coding with code generators like Xtext.
  • Modernize your development environment
    • Share knowledge and open up towards other (maybe younger) developers (Java etc.).
    • Be and stay attractive as a company to new employees.
    • Automate your build process
    • NaturalONE is Software AG’s platform of choice for the future.
    • The old Natural editor will be shut down!
  • Extendable with additional plugins
    • Software AG’s innovations will only take place in NaturalONE (e.g. Code Coverage, Screen Testing).
    • Attach your IDE to an issue tracker like Jira or Redmine with Mylyn.
    • Use Snipmatch for even less typing. Plugin Snipmatch used in NaturalONE
    • Create your own extensions (e.g. NatUnit) for whatever requirement you have.
      Our own NatUnit plugin used in NaturalONE

Recommended reading

  • NaturalOne Debugging

Links

Automating Your Natural Build Process – Legacy Coder Podcast #2

Automating Your Natural Build Process

How can you automate the build process for your application based on Software AG’s Adabas and Natural? I talk about our journey towards a completely automated build from scratch after each push to Git in the second episode of the Legacy Coder Podcast.

How to automate the build process for an Adabas/Natural application

  • Why would I want to automate the build process?
    • What hurts should be done more often!
    • No more long integration phases before each release!
    • You’ll get a faster time to market for new features.
    • You can get rid of knowledge silos concerning the release of your application.
  • What steps may need to be automated?
    • Upload (transfering the Natural source code to the server)
    • Compile (CATALOG, STOW, CATALL etc.)
    • Unit Tests (e.g. with NatUnit, see Unit Testing Natural Applications)
    • Deployment (the actual release of the new version on the target stage)
    • Restarting RPC servers or whatever individual steps might be necessary in your environment
  • What tools are available for automating the Natural build process?
    • It all starts with Git or any other versioning control system (Subversion, TFS, CVS).
    • You can use Jenkins for Continuous Integration.
    • Software AG’s command line tools (ftouch etc.) can be scripted.
    • Even the CATALL can be scripted by calling into Natural BATCHMODE.
    • NaturalONE’s ant scripts for uploading and compiling Natural sources.
    • Any additional tool that you might need (Bash scripts etc.)
  • How can I get started?
    • Make your project fully compilable. There can be no compile errors whatsoever.
    • Start with a single step, e.g. automate only the compile step first.
    • Script everything (e.g. with Bash) right from the beginning. You can easily call these scripts from Jenkins later on.
    • Hook Jenkins up to your source code repository. It provides plugins for every major system (e.g. Git, Subversion).
    • Try to automate the build with Jenkins. It’s completely free and easy to setup. Perhaps ask a Java colleague if he can help you.
  • How can you go even further than what’s possible today?
    • Try to automate imports of Adabas data that’s important for your application.
    • Try to automate Adabas schema migrations.
    • Implement feature toggles for more fine grained control over your application’s functionality at runtime.

Recommended reading

Links

Unit Testing Natural Applications – Legacy Coder Podcast #1

Unit Tests for Natural Applications with NatUnit

Unit testing with Software AG’s Natural – is that even possible? Let’s find out in the very first episode of the Legacy Coder Podcast.

Unit testing Natural applications

  • Why would I want to unit test my Natural code?
    • You get instant feedback whether your code works. That’s fun! 😀
    • You get a safety net for refactoring and optimizing your Natural code.
    • You can catch regression as early as possible. That makes evolving your code base easy and painless.
    • Unit tests can be integrated into your build process (Continuous Integration, Continuous Delivery, Continuous Deployment).
    • Unit tests are the first step on your way to a fully automated build process.
  • What tools are available for unit tests with Natural?
    • Subprogram testing within NaturalONE
      • Only subprograms can be tested.
      • Different “language” for defining your tests.
      • Tests have to be defined manually from a GUI.
      • Tests cannot be executed from within Natural itself.
      • Proprietary software maintained by Software AG.
      • Professional support by Software AG is available.
    • NatUnit – an open source framework for unit testing with Natural
      • Everything that can be called from a subprogram can be tested (subprogram, subroutine, function).
      • Tests are written in the same language that is used for production code.
      • Tests can be written as Natural code with full IDE support.
      • Tests can be executed within any Natural runtime.
      • Open source project that can be extended by everybody – including yourself.
      • There’s no professional support for the framework.
  • What do I have to do differently when writing testable Natural modules?
    • You need more fine grained modularization!
    • You have to decouple the User Interface, Database access, and the core Business Logic from each other.
    • You need to extract the functionality to test into its own callable module.

NatUnit in action

Here are a few screenshot of our NatUnit Eclipse plugin in action.

You can run a NatUnit test from within the IDE.

NatUnit Eclipse Plugin: RunAs NatUnit Test

If the tests are successful, you instantly see the famous “green bar”.

NatUnit Eclipse Plugin: Successful Test

And if the tests are broken, you’ll definitely notice that, too. 😉

NatUnit Eclipse Plugin: Failing Test

Recommended reading

Links

Introduction to the show and the host – Legacy Coder Podcast #0

Legacy Coder Podcast Episode 0: Introduction to the show and the host

Who is this guy and what the heck does he know about Software AG’s Adabas and Natural? I’ll show you in the pre-episode zero of the Legacy Coder Podcast.

Introduction to the podcast and myself

  • My experience with Adabas and Natural.
    • I’m programming with Natural since 2003.
    • I’m the president of the International Natural User Group since 2016.
    • I co-authored NatUnit (as part of my Master’s thesis) and L4N.
    • My main job is integrating Adabas/Natural into a modern SOA with webMethods Integration Server.
    • In the last few months I automated and modernized the Natural build process with Git, Jenkins, Java, and NaturalONE.
    • My biggest Natural project so far was the migration of an insurance system from Oracle/Java to Adabas/Natural.
    • I frequently speak at local and international user groups and conferences (e.g. Innovation World, Innovation Tour, IUG).
    • Our Natural code base: ~6 million LOC, ~19.000 modules.
  • My professional experience.
    • I studied business computer science (Bachelor’s degree) and software engineering (Master’s degree).
    • I train new hires and apprentices at ALTE OLDENBURGER Krankenversicherung AG in Germany.
    • I also use a few additional languages: Java, C#, PHP, Ruby.
    • I’m a software architect since 2014.
    • I work as an associate professor for programming and software engineering at PHWT since 2009.
  • My personal life.
    • I’m married.
    • I have two dogs.
    • I like taking photos.
    • I run a podcast for aspiring software developers in German.
    • I organize my own user group and conference for software developers.
    • You can find me almost everywhere: LinkedIn, Twitter, Instagram etc.

Links

Exception-like error handling in Software AG’s Natural

Error handling in Software AG’s Natural can be done in a way that resembles Exception handling in object-oriented languages like Java.

throw

Instead of throwing an Exception, you raise an error simply by assigning a value to the system variable *ERROR-NR. As soon as a statement like the following is executed, the current program flow is interrupted and the nearest ON ERROR block is executed.

*ERROR-NR := 1234

In fact, we use exactly this feature for raising assertion errors in NatUnit.

catch

You can handle a Natural error in an ON ERROR block anywhere inside your code. Just like an Exception travels up through the call stack to get caught in the nearest try-catch block, a Natural error is handled in the nearest ON ERROR block.

Here’s an example of an ON ERROR block that exits the current module and marks the error as handled:

ON ERROR
    /* do something about it */
    ESCAPE MODULE
END-ERROR

catch (SpecificException e)

You can only define a single ON ERROR block in each Natural module. So if you need to handle specific errors in a different way, you need to have some kind of distinction logic like this:

ON ERROR
    IF *ERROR-NR EQ 1234
        /* do something about it */
        ESCAPE MODULE
    END-IF
END-ERROR

Or if you need to distinguish between multiple errors:

ON ERROR
    DECIDE ON FIRST VALUE OF *ERROR-NR
        VALUE 1234
            /* do something about it */
            ESCAPE MODULE
        VALUE 1235
            /* do something about it */
            ESCAPE MODULE
        NONE IGNORE
    END-DECIDE
END-ERROR

re-throw

If you can’t handle the error in an ON ERROR block, but you want to log it or do something else with it before letting the next ON ERROR block handle it, you don’t need to do anything at all, because that’s the default behaviour.

However, if you exit the ON ERROR block with any statement from the following list, the error is marked as handled and the normal control flow (in the calling module of the module containing the ON ERROR block) is continued. So be sure not to exit the block with any of these statements.

Exiting from an ON ERROR Block:
An ON ERROR block may be exited by using a FETCH, STOP, TERMINATE, RETRY, ESCAPE ROUTINE or ESCAPE MODULE statement. If the block is not exited using one of these statements, standard error message processing is performed and program execution is terminated.

Here’s an example of such a “re-throw”:

ON ERROR
    IF *ERROR-NR EQ 1234
        /* log the error */
        /* DON'T exit with `FETCH`, `STOP`, `TERMINATE`, `RETRY`, `ESCAPE ROUTINE` or `ESCAPE MODULE` */
    END-IF
END-ERROR

Checking which error occurred

Even if you “handle” the Natural error in an ON ERROR block, e.g. by using ESCAPE MODULE, the system variable *ERROR-NR isn’t reset to 0. You need to do that yourself, if you need to. If you don’t, the variable can be used in the calling module to check whether an error (that was handled) occured. By the way, the system variable *ERROR-LINE contains the line number of the statement that raised the error.

CALLER

CALLNAT 'CALLEE'
IF *ERROR-NR NE 0
    WRITE 'Error' *ERROR-NR 'occurred in line' *ERROR-LINE 'while calling CALLEE'
    /* prints: "Error     1234 occurred while calling CALLEE" */
END-IF
END

CALLEE

*ERROR-NR := 1234
ON ERROR
    ESCAPE MODULE
END-ERROR
END

If you don’t want any caller to know that an error occurred, simply reset *ERROR-NR:

ON ERROR
    RESET *ERROR-NR
    ESCAPE MODULE
END-ERROR

Global error handler (like a try-catch in main())

You can define a global error handler by setting the system variable *ERROR-TA to the name of a Natural module. In case of an error, Natural automatically calls this module (which has to be a program) and puts information about the error on the stack. The system variables *ERROR-NR and *ERROR-LINE will be reset at this point, so the error handler has to read the information from the stack with INPUT.

CALLER

*ERROR-TA := 'HANDLER'
CALLNAT 'CALLEE'
END

CALLEE

*ERROR-NR := 1234
END

HANDLER

DEFINE DATA LOCAL
1 #ERROR-NR           (N5)
1 #LINE               (N4)
1 #STATUS-CODE        (A1)
1 #PROGRAM            (A8)
1 #LEVEL              (N2)
1 #LEVELI4            (I4)
1 #POSITION-IN-LINE   (N3)
1 #LENGTH-OF-ITEM     (N3)
END-DEFINE

/* read error information from stack */
INPUT #ERROR-NR #LINE #STATUS-CODE #PROGRAM #LEVEL #LEVELI4

WRITE #ERROR-NR #LINE #STATUS-CODE #PROGRAM #LEVEL #LEVELI4 #STATUS-CODE
WRITE *ERROR-NR *ERROR-LINE

END

Output:

1234    10 O CALLEE     2           0 O
     0     0

For more information about the error information on the stack take a look at the section Using an Error Transaction Program in the Natural documentation.

Getting more information about errors programmatically

If you need to find out more about the current error, e.g. in your ON ERROR block, there are quite a few User Exits that deal with errors:

  • USR0040N: Get type of last error
  • USR1016N: Get error level for error in nested copycodes
  • USR2001N: Get information on last error
  • USR2006N: Get information from error message collector
  • USR2007N: Get or set data for RPC default server
  • USR2010N: Get error information on last database call
  • USR2026N: Get TECH information
  • USR2030N: Get dynamic error message parts from the last error
  • USR3320N: Find user short error message (including steplibs search)
  • USR4214N: Get program level information

Automatically reconnect to a database after a failure in JBoss EAP 7

My JBoss EAP 7 server couldn’t cope with a failing database. After a database restart or failure, e.g. due to maintenance, it simply would not connect to the database again automatically. The application simply stopped working as soon as the database was unavailable for a short period of time.

JBoss’s server.log was full of (not very helpful) error messages like this:

2017-03-01 12:05:18,175 ERROR [it.macke.repository.UserRepository] (default task-17) Error reading user: org.hibernate.exception.JDBCConnectionException: could not prepare statement: javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: could not prepare statement
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1692)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1602)
...
Caused by: org.hibernate.exception.JDBCConnectionException: could not prepare statement
    at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:48)
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:42)
...
Caused by: java.sql.SQLNonTransientConnectionException: Connection is close
    at org.mariadb.jdbc.internal.util.ExceptionMapper.get(ExceptionMapper.java:123)

To make the application work again, I had to restart JBoss and every now and then even the whole Windows server on which it runs.

As it turns out, this is a common problem with JBoss. However, the solution is quite easy. You only need to configure JBoss to validate the database connections. Here’s how this would look in standalone.xml (take a look at the content of element validation):

<datasource jndi-name="java:jboss/jdbc/MyDS" pool-name="MyDS">
    <connection-url>jdbc:mariadb://localhost:3306/login</connection-url>
    <driver-class>org.mariadb.jdbc.Driver</driver-class>
    <driver>mariadb</driver>
    <security>
        <user-name>user</user-name>
        <password>secret</password>
    </security>
    <validation>
        <check-valid-connection-sql>select 1</check-valid-connection-sql>
        <validate-on-match>true</validate-on-match>
        <exception-sorter class-name="org.jboss.jca.adapters.jdbc.extensions.mysql.MySQLExceptionSorter"/>
    </validation>
</datasource>

And if you want to script the setting, here’s the code for the CLI:

/subsystem=datasources/data-source=MyDS:write-attribute(name=validate-on-match,value=true)
/subsystem=datasources/data-source=MyDS:write-attribute(name=check-valid-connection-sql,value="select 1")
/subsystem=datasources/data-source=MyDS:write-attribute(name=exception-sorter-class-name,value="org.jboss.jca.adapters.jdbc.extensions.mysql.MySQLExceptionSorter")

The above settings make JBoss validate the connection on every new request (validate-on-match). But you can also have it do the checking in the background, e.g. every few seconds. And you need to consider the correct setting for your database. I use MariaDB/MySQL for my application and the exception-sorter and check-valid-connection-sql might be different depending on your database (e.g. org.jboss.jca.adapters.jdbc.extensions.oracle.OracleValidConnectionChecker and select 1 from dual for Oracle). Take a look at the available parameters here: Database Connection Validation JBoss EAP 7 – Configuration Guide

How to find the physical file path of the current FUSER of a Natural runtime

Here’s a short subroutine for reading the physical file path of the current FUSER of a Natural (from Software AG) runtime. I’m not sure if it works on a mainframe, but it definitely runs on a Linux system.

The subroutine returns the following information, if it runs successfully:

P-FUSER-PATH /home/macke/fuser
P-RC 0

Otherwise the return code P-RC will have a value other than zero.

It uses two user exits:

  • USR6006N: Get path to system file
  • USR2013N: Get SYSPROF information

USR2013N reads the information about the current FUSER and returns its DB-ID and File Number. And USR6006L takes these two inputs and returns the physical file path of the FUSER.

Subroutine GET-CURRENT-FUSER-PATH

**************************************************************************
*
*  File: GET-CURRENT-FUSER-PATH (VNGFUPAT)
*
*  Reads the physical file path for the current FUSER.
*
*  Tags: FUSER, UserExit
*
*  Parameters:
*    -
*
*  Returns:
*    P-FUSER-PATH - File path for the current FUSER.
*    P-RC - Return code
*
**************************************************************************
DEFINE DATA
*
PARAMETER
*
01 P-RC (I4) BY VALUE RESULT
01 P-FUSER-PATH (A) DYNAMIC BY VALUE RESULT
*
LOCAL
*
* Get path to system file
01 USR6006L
  02 INPUTS
    03 SYSF-DBID (I4)
    03 SYSF-FNR (I4)
  02 OUTPUTS
    03 SYSF-PATH (A253)
    03 RESPONSE-CODE (I4)
    03 INFOTEXT (A65)
01 EXTENSIONS (A1/1:1)
*
* Get SYSPROF information
01 USR2013L
  02 OUTPUTS
    03 FILENAME (A12/1:50)
    03 DBID (P5/1:50)
    03 FNR (P5/1:50)
    03 DBNAME (A11/1:50)
    03 AMOUNT (P4)
*
01 #INDEX (I4)
*
01 #FUSER-DBID (N8)
01 #FUSER-FNR (N8)
*
END-DEFINE
*
DEFINE SUBROUTINE GET-CURRENT-FUSER-PATH
*
RESET P-FUSER-PATH P-RC USR6006L USR2013L EXTENSIONS(*) #FUSER-DBID #FUSER-FNR
*
CALLNAT 'USR2013N'  USR2013L
*
FOR #INDEX = 1 TO USR2013L.AMOUNT
  IF USR2013L.FILENAME(#INDEX) EQ 'FUSER'
    #FUSER-DBID := USR2013L.DBID(#INDEX)
    #FUSER-FNR  := USR2013L.FNR(#INDEX)
  END-IF
END-FOR
*
IF #FUSER-DBID EQ 0 OR #FUSER-FNR EQ 0
  P-RC := 1
  ESCAPE MODULE
END-IF
*
USR6006L.SYSF-DBID := #FUSER-DBID
USR6006L.SYSF-FNR  := #FUSER-FNR
*
CALLNAT 'USR6006N' USR6006L EXTENSIONS(*)
*
P-FUSER-PATH := USR6006L.SYSF-PATH
P-RC := USR6006L.RESPONSE-CODE
*
END-SUBROUTINE
*
END

How to combine/join file paths in Gradle/Groovy

One might think that joining (or combining) two file paths together with Groovy would be an easy thing to do. I’m used to “nice” methods from Ruby like File.join (see How to do a safe join pathname in ruby?):

File.join("path", "to", "join")

As it turns out, there is no such method in Groovy. However, here are two easy ways to safely combine paths in Groovy (which I use in my Gradle build):

import java.nio.file.Paths // only needed for second example

def dir1 = "/the/path"
def dir2 = "to/join"

println new File(dir1, dir2)
println Paths.get(dir1, dir2)
// -> both print "\the\path\to\join" (on my Windows machine)