Handling wlst exception in python script

Question

I'm maintaining a build that is interrupted when trying to delete missing MDS partition.

It's fine when there's stuff to remove.

I'm not so familiar with the subject and I'd like to either

check partition presence before removal
handle error and continue maven life-cycle

pom part in question is

      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.1</version>
        <executions>
          <execution>
            <id>delete-MDS</id>
            <phase>pre-integration-test</phase>
            <goals>
              <goal>exec</goal>
            </goals>
            <configuration>
              <executable>${oracle.wlst}</executable>
              <arguments>
                <argument>${predeploy.script.deletemds}</argument>
                <argument>weblogic</argument>
                <argument>${adminServerPassword}</argument>
                <argument>${adminServerUrl}</argument>
                <argument>${mds.repository}</argument>
                <argument>${mds.partition}</argument>
              </arguments>
            </configuration>
          </execution>
        </executions>
      </plugin>

${predeploy.script.deletemds} content is

print '\nStarting deleteMDSOnDomain.py'

#skipped mapping input to variables here

try:
  connect(username,password,url)

  print "Deleting MDS configuration"
  #fails if partition already removed
  deleteMetadataPartition( repository=mdsRepository, partition=mdsPartition)

except Exception, e:
  print e
  print "Error while trying to delete MDS configuration"
  dumpStack()
  #raise

print 'Finished deleteMDSOnDomain.py\n'

When running it I get

...
[INFO] Deleting MDS configuration
[INFO] Location changed to domainRuntime tree. This is a read-only tree with DomainMBean as the root.
[INFO] For more help, use help(domainRuntime)
[INFO]
[INFO]
[INFO] Problem invoking WLST - Traceback (innermost last):
[INFO]   File "C:\Dev\trunk\<App>\<Project>\scripts\deleteMDSOnDomain.py", line 24, in ?
[INFO]   File "C:\Dev\Oracle\MIDDLE~1\ORACLE~1\common\wlst\mdsWLSTCommands.py", line 471, in deleteMetadataPartition
[INFO]   File "C:\Dev\Oracle\MIDDLE~1\ORACLE~1\common\wlst\mdsWLSTCommands.py", line 836, in executeDomainRuntimeMBeanOperation
[INFO]   File "C:\Dev\Oracle\MIDDLE~1\ORACLE~1\common\wlst\mdsWLSTCommands.py", line 1097, in saveStackAndRaiseException
[INFO] WLSTException: MDS-00555: The partitionName <App> is invalid.
[INFO] ORA-01403: no data found
[INFO] ORA-06512: at "<env>_MDS.MDS_INTERNAL_SHREDDED", line 580
[INFO] ORA-06512: at line 1
[INFO]  MDS-91009: Operation "deleteMetadataPartition" failure. Use dumpStack() to view the full stacktrace.
[INFO]
[INFO] ------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] Result of cmd.exe /X /C "C:\Dev\Oracle\Middleware\oracle_common\common\bin\wlst.cmd scripts/deleteMDSOnDomain.py weblogic <pass> <url> mds-CustomPortalDS <App>" execution is: '1'.
[INFO] ------------------------------------------------------------------------

It appears that wlst result "1" is propagated to maven, e.g. my py catch isn't fully handling that - can I manually change it to "0, ok" there?

Edit: typos

All is caught fine. The error is raised by another plugin that attempts to undeploy the application next. Just realized it after noticing

[INFO] [Deployer:149001]No application named '<app>' exists for operation undeploy.

I could swear it wasn't there before ... Anyway I got some code to check for partition existence in the answer below too.

It seems like you should be catching the error. What does `deleteMetadataPartition` look like? You can call `exit()` which will default to 0 at the end of your script. — Display Name is missing, Mar 05 '15 at 16:21
Unfortunately deleteMetadataPartition is proprietary magic http://docs.oracle.com/cd/E28271_01/web.1111/e13813/custom_mds.htm#CHDEHHHE — arkonautom, Mar 05 '15 at 16:50

score 1 · Accepted Answer · answered Mar 06 '15 at 13:45

I'm more of a Look Before You Leap sort of programmer so below is some WLST I used when removing MDS partitions to check they exist first. Unfortunately you have to resort to accessing the MDSDomainRuntime mBean directly as someone forgot to expose the listPartitions methods in WLST.

from org.python.modules import jarray
from javax.management import ObjectName, Attribute

#skipped mapping input to variables here

connect(username, password, url)

domainRuntime()

mdsName = ObjectName('oracle.mds.lcm:name=MDSDomainRuntime,type=MDSDomainRuntime')
beans = mbs.queryMBeans(mdsName, None)

if (beans.size() == 0):
    # This _should_ be impossible
    raise Exception("Could not find mbean '%s' in the current tree '%s'." % (mdsName, pwd()))

beanName = beans.iterator().next().getObjectName()
params = jarray.array([mdsRepository], java.lang.Object) 
signature = ['java.lang.String']  
partitions = mbs.invoke(beanName, "listPartitions", params, signature)  

if (mdsPartition not in partitions):  
    print("Partition '%s' does not exist in repository '%s'." % (mdsPartition, mdsRepository))
else:
    params = jarray.array([mdsRepository, mdsPartition], java.lang.Object)
    signature = jarray.array(['java.lang.String','java.lang.String'], java.lang.String)
    mbs.invoke(beanName, 'deleteMetadataPartition', params, signature)
    print("Partition '%s' deleted from repository '%s'." % (mdsPartition, mdsRepository))

Handling wlst exception in python script

1 Answers1