Difference between revisions of "SMILA/FAQ"

Latest revision as of 12:22, 25 February 2016

This pages contains the frequently asked questions of the SMILA project.

General Hint: When you have problems during a SMILA launch / run, please have a look at the SMILA log file first. (<SMILA>/SMILA.log)

General

Where do I find the log file?

The SMILA log file's name is SMILA.log and is to be found at the applications working folder:

If you extracted SMILA from a zip, you can find the log file in the folder, where you extracted the SMILA.

/<SMILA>
  ...
  SMILA.log
  ...

If you started SMILA from within the Eclipse IDE using the launcher, you can find the log file at the project SMILA.application in your workspace.

How can I see that SMILA started correctly?

1. Open your browser at http://localhost:8080/smila, you should see a system state overview and links to different APIs.

2. You should see no stacktraces in the log ;) and it should end with an entry like the following if SMILA has just started:

... INFO  ... internal.HttpServiceImpl    - HTTP server started successfully on port 8080.

Building SMILA

I receive an Out of Memory error? What can I do?

While building with SMILA.builder I receive the following errror message:

Build Failed - Out of Memory - Java heap space

The reason for this is that Ant hasn´t enough heap space to build the project. You will have to expand the heap space by setting the VM arguments accordingly. In eclipse try the following:

1. Click Open external tools dialog and select your Ant build profile.
2. Switch to the JRE tab and add the following VM arguments: -Xms40m -Xmx512m.
3. Save and build again.

Build fails with 'java.net.MalformedURLException: no protocol: ${eclipseBaseURL}' message

The complete error looks like this:

...
build.core:
     ...
     [java] BUILD FAILED
     [java] /home/scum36/Eclipse/helios-sr2-build/plugins/org.eclipse.pde.build_3.6.2.R36x_20110203/scripts/productBuild/productBuild.xml:33: The following error occurred while executing this line:
     [java] /home/scum36/Eclipse/helios-sr2-build/plugins/org.eclipse.pde.build_3.6.2.R36x_20110203/scripts/build.xml:53: The following error occurred while executing this line:
     [java] /home/scum36/workspace/SMILA/SMILA.builder/customTargets.xml:80: The following error occurred while executing this line:
     [java] /home/scum36/workspace/SMILA/SMILA.builder/customTargets.xml:25: java.net.MalformedURLException: no protocol: ${eclipseBaseURL}
     [java] 
     [java] Total time: 0 seconds
     [java] An error has occurred. See the log file
     [java] /home/scum36/workspace/.metadata/.log.

Probably you did forget to copy build.properties.template to build.properties in SMILA.builder and adapt it. See How to build SMILA.

Launching SMILA

Linux

How to start/stop and manage SMILA as a background process on a Linux machine?

Since the default configuration (stored in SMILA.ini) of the OSGi runtime (in our case Equinox) launcher expects that you execute it in foreground and therefore have an OSGi console running in your shell and listening to the standard input, the first thing we have to do is to advise the launcher (and thereby Equinox) to listen on some TCP port instead. This is done by adding a new line with the port number just after the "-console" line.

For example, to set console to listen at TCP port 9999, SMILA.ini would look like this:

 -console
 9999
 ...

Now, after SMILA has been started with “$ nohup ./SMILA &”, the console can be accessed from any computer simply by opening a telnet session:

$ telnet <smila_host_name> <console_port>

If you are logged in via telnet and just want to close this connection and not to stop Equinox running SMILA, than just type “disconnect”. Otherwise, if you want to stop SMILA and close the connection, use “close” - as you normally would do on a console running in your shell.

Bundles

new bundle was not started

After launching SMILA my new bundle doesn't seem to be started.

If you started SMILA.launch in eclipse to launch SMILA: The launcher didn't start your new bundle. Try this:

1. Add your bundle by selecting "Run Configurations" in eclipse and choose your SMILA profile.
2. Select your bundle in the list and set the checkmark.
3. Set the start level to "4" and the autostart to "true".

If you started SMILA.EXE to launch SMILA: Your bundle isn`t defined in config.ini or the start level isn´t correct. Try this:

1. Open the file configuration/config.ini and add your bundle as shown below:
   

   org.eclipse.smila.connectivity.framework.crawler.owncrawler@5:start, \
   

2. Open the build.properties file of your bundle and include the folders schemas/, OSGI-INF/, and the file plugin.xml.

I changed bundle settings in my config.ini, but after SMILA restart nothing changed

Check your config.ini for unusual whitespaces (e.g. a tab) between the (edited) bundle entries or after the backslashes on line ends - and remove them.

If that doesn't help, see question (resp. answer) before.

Configuring/Running SMILA

Basics

How do I change the HTTP port of SMILA?

The HTTP port is configured in fie configuration/org.eclipse.smila.clusterconfig.simple/clusterconfig.json. Change it there and restart SMILA.

See SMILA/Documentation/JettyHttpServer#Setting_the_HTTP_port for details.

Crawler

I started a crawl job, the job was started successfully, but nothing seems to happen

Check the SMILA log file for errors.

Check the state of the crawl job in jobmanager state API

• if the state in your crawl job is "RUNNING", check the mode it has been started
  • if it says "mode": "STANDARD", stop the job run (POST http://localhost:8080/smila/jobmanager/jobs/<job name>/<job run id>/finish) and start it again with mode "runOnce", e.g. POST http://localhost:8080/smila/jobmanager/jobs/<job name> {"mode": "runOnce"}
• if the state is FINISHING
  • check the job into which the crawl job pushes its records for processed records or errors.
• if everything up to now is OK
  • just wait some time, the autocommit handler maybe hasn't yet committed the data to the Solr index
  • check autoCommit settings in the solrconfig.xml file of your Solr core.

Pipeline

Why do I get a timeout exception during a (long running) pipeline execution?

In SMILA there's a timeout configured for a pipeline execution:

configuration/org.eclipse.smila.processing.bpel/processor.properties

See entry: pipeline.timeout

My xpath expression doesnt work

1. Check that the expression is correct with a XPath tool
2. ensure that the attributes are not filtered out, see SMILA/Documentation/HowTo/How_to_filter_and_access_record_data_in_BPEL

Helpful log points

Implementing Pipelets / OSGi Services / Bundles

Pipelets

I want to use the ConfigUtils class in my Pipelet to read the configuration, where do I have to put my configuration files?

Configuration files are searched for in the following order:

1. <SMILA>/configuration/<bundle-name>/<config-file>
2. <config-file> in the root path of the bundle jar-file

See Configuration Handler for more information.

I get classloading errors in invocations of my own Pipelet when running SMILA outside the IDE. In the IDE it works

The error could look like this:

2010-11-19 11:28:36,101 ERROR [ODEServerImpl-1
]  vpu.JacobVPU                                  - Method "run" in class "org.apache.ode.bpel.rtrep.v2.EXTENSIONACTIVITY" threw an unexpected exception.
java.lang.LinkageError: loader constraint violation: loader (instance of org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader) previously initiated loading for a different type with name "org/w3c/dom/Document"

We are not completely sure, why this happens, but a solution is to set this system property in the SMILA.ini file:

-Dosgi.java.profile.bootdelegation=override

Thanks to Bogdan Sacaleanu for the solution. See this thread in the smila-dev mailing list for additional details.

OSGI-Services / Workers

I implemented/deployed an OSGi Service but it seems that it isn't activated

Check your bundle, it should contain a file like that:

OSGI-INF/<myService>.xml

In this file your service has to be referenced.

• the component name in the root element must be unique
• the implementing class must not be abstract and must not be an interface

The file has to be referenced in the META-INF / MANIFEST.MF file of your bundle as a service component:

Service-Component: OSGI-INF/<myService>.xml

On the "Build" page of the manifest editor, you must add the OSGI-INF directory to the binary build.

And finally, your bundle has to be started at SMILA launch, by adding it to the configuration/config.ini

...
<bundle-id>@4:start,
... 

If you are using <tt>SMILA.launch to launch SMILA in eclipse IDE, you have to open the run/debug configuration of SMILA, check the new bundle and set Auto-Start to "true".

If you checked all the things above and it still doesn't work:

• Implement an activate() method in your service - if not already there, and check if it's called at startup.
• If your service depends on other services, check if those are activated
• If your service uses other services, check the naming of the set/unset methods in the Java code vs. those specified in the <myService>.xml
• If your services uses 3rd-party-jars, make sure that they are specified in the Bundle-ClassPath section of your MANIFEST.MF (Do not reference the lib folder here, instead reference all jars, e.g. Bundle-ClassPath: ., <lib1.jar>, <lib2.jar>). Make also sure, that they are added to the binary build ("Build" page of the manifest editor).
• If your service has super-classes you may need to include Import-Package: declarations of the super-classes in your service implementation class even if there are no compile errors.
• Use the OSGi console, e.g. via: telnet <host> 9005
  • ss <bundle-ID> - check if your bundle is in the list and ACTIVE (the bundle-ID is the "Bundle-SymbolicName" from the MANIFEST.MF)
    • if it isn't in the list, the bundle is not correctly deployed
    • if it isn't ACTIVE but only RESOLVED it's not started (-> see hints above)
  • bundle <id> - check if your service is listed here in the "Registered Services" section (the "id" can be taken from the "ss" output)
    • if it isn't there, your service is not correctly deployed (-> check all points above)

My activate() / deactivate() method isn't called

Check that your activate/deactivate method is protected or public.

If you use activate()/deactivate() methods without (ComponentContext) parameter, make sure that your service description xml file contains scr namespace:

<?xml version="1.0" encoding="UTF-8"?>
<scr:component xmlns:scr="http://www.osgi.org/xmlns/scr/v1.1.0" ...

I implemented a worker, everything seems fine, but the worker processes no tasks during the job run

Make sure that your worker is actually running.

In the REST API, the worker description must be found via: http://localhost:8080/smila/jobmanager/workers

Check also if your worker is really started via debug API: http://localhost:8080/smila/debug

A warning is shown here, if your worker coudn't be found, e.g.:

  ...
  name: "myWorker",
  WARNING: "Worker is not registered in WorkerManager. Maybe worker OSGI service isn't started or worker's name setting is inconsistent."
  ...

If you get something like this, try to check FAQ for implementing an OSGI service above.

General

I get classloading errors when I try to access an external Web Service using JAX-WS

Class loading problems often occur when using third party libraries that use the "thread context classloader" in OSGi, and standard implementations of Java specifications by Sun/Oracle (or other non-OSGi-aware parties...) do this very often.

The only solution we currently know of is to wrap the critical section (in this case it's the construction of the webservice client class) in a piece of code like this:

ClassLoader tccl = Thread.currentThread().getContextClassLoader();
try {
    Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
    /*
     * initialize the client
     */
} finally {
    Thread.currentThread().setContextClassLoader(tccl);
}

See also this forum thread.

More classloader errors

If you get an error like this:

Caused by: java.lang.LinkageError: loader constraint violation: when resolving field "DATETIME" the class loader (instance of 
 org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader) of the referring class, javax/xml/datatype/DatatypeConstants, and the class loader (instance of <bootloader>) for the field's resolved type, javax/xml/namespace/QName, have different Class objects for that type

the reason is most likely that you have classes in the bundle classpath of your bundle that contains classes which are also part of the JDK runtime library (java.*, javax.*). Remove these classes from the bundle and it should work.

See also this forum thread.