Welcome!

Weblogic Authors: Elizabeth White, Michael Meiner, Michael Bushong, Avi Rosenthal

Related Topics: Weblogic

Weblogic: Article

Monitoring and Controlling WebLogic Servers with WLST

Writing scripts merged with Java is more natural than ant

Scripting languages have recently garnered a bit of attention. With the arrival of Groovy and Jython, writing scripts merged with Java is more natural than Ant. Using XML to call Java methods has always been forced, mostly because it's hard to express flow, conditional expressions, and custom Java code in a markup language (although things have improved a lot since Ant 1.5).

Why a scripting language? Well, if I have a completely blown IDE for Java programming, using Jython or Groovy can look backwards. You can code in fewer lines (though not much less), but I want the imports written automatically. I want compiler warnings while coding and I need refactorings. Plug-ins for these languages are still outside of Java IDE's capabilities.

But there are times where you just don't have a full IDE configured. Think about jobs that should be automated to be agile, or about server administrators. These people don't have anything like Eclipse, and their work can't be done in advance. You can't code for system administration. This is where tools like WLST come in and make the world a better place.

WLST (WebLogic Scripting Tool) is a Jython module that helps write scripts to administer and modify a server installation remotely. It comes in two flavors: offline, which can configure a server instance that doesn't exist yet, and online, which needs a WebLogic server to connect to. Both versions are in beta and are poorly documented, but they promise to improve and will be in some future WebLogic release.

We're going to focus on the online version here, because its functionalities are more complete than the offline version.

Automating Server Configuration:
Let's start by getting rid of that nasty WebLogic server configuration. Your typical development team replicates the same config in several hosts, changing only a couple of parameters such as the IP, hostname, and TCP port. In a relatively typical project, the process must be executed for each developer's PC, integration test host, and production. Ant tasks resolve great in this context, but it's not prepared to handle things like custom JMX beans.

We're going to create and launch the server, configure it, and do a shutdown, using a mixture of ant and WLST. First, let's create the server in Listing 1. For simplicity's sake, we're going to use the ant task here because combining WLST offline and online would mess things up.

I check the properties because when you deploy on more than one brand of app server it's easy to use the wrong build.properties file (see Listing 2).

We have just removed the whole domain directory, created a new clean one, and left the server running, so now in Listing 3 we can connect and configure it.

The server stop is necessary because some setting changes, i.e., security authenticators, need a graceful shutdown to be stored on disk. Omitting this step would kill the server in a hard way at the end of the ant script

Note: the WLST task is forked, and so, if WLST finds an error in your script, ant still will say "build successful," something that might confuse the person launching the script.

Let's split the WLST script into two parts to reuse as much of it as possible for administration tasks later. I have used the great examples enclosed with the WLST bundle and the output of the saveDomain() command as starting points. The saveDomain() generated script isn't very polished, but it serves to indicate the tool's possibilities (see Listing 4).

The loadProperties task converts all the entries in the administration.properties file to Jython variables. We've used the first methods of a Jython class to administrate the WebLogic server instance. It can easily be extended to create and remove DataSources, a JMS environment, and even security realms.

MBean Methods
What you have seen is a way of creating and configuring MBeans (there's another way that will be explained in the next section). The downside is that you have to know the attributes and methods supported, and WLST doesn't document them. How can I guess which methods are available?

Well, the first way that comes to mind is going to the config.xml file or the web console and assume the attribute names hasn't changed. If we have a decent IDE we also can open the MBean interface class and see what's in there (it's the same as the MBean name, ending with 'MBean'). It won't show you code, but you can check which methods are available.

I prefer connecting to http://e-docs.bea.com/wls/docs81/javadocs/index.html and checking the contents of the package weblogic.management.configuration. For example, if we go to the ServerMBean class, we can see two interesting and not particularly well-known methods isJDBCLoggingEnabled() and setJDBCLoggingEnabled(). We can check them by opening the wlst interactive shell as laid out below:

 


wls:/mydomain/config> server=home.getAdminMBean('myserver', 'Server')
wls:/mydomain/config> server.setJDBCLoggingEnabled(1)
wls:/mydomain/config> server.isJDBCLoggingEnabled()
1

('home' is a variable of type AdminMbeanHomeImpl and can be studied as any other MBean; the only problem is that there's no javadoc available since it's an internal class).

If these last three commands aren't easily understood, don't worry. The shell will be covered in the next section.

Command Line System Administration
A system administrator can also administer the WebLogic server instance manually by using the interactive shell. The advantage here is you don't have to know a priori the MBean interfaces when trying to modify the system config. For this part, you have to include weblogic.jar, jython.jar, and wist.jar in the classpath and start the main class weblogic.WLST, which is the interactive console.

Keep it mind that this is Jython. Quotes and double quotes are used for string delimitation; instantiation doesn't need a new operator (as a matter of fact it's a syntax error); semicolons aren't required because each line ends with a carriage return; and variables don't have to be declared (a la Unix shell scripts). If that's not enough for you, please refer to the Python and WLST docs.

We need to start connecting to a WebLogic server instance. We can choose to use the AdminTool script developed before, or connect manually:

 


execfile('AdminTool.py')
admin.connect()

or

 


connect('weblogic', 'weblogic', "t3://localhost:7001)

Connecting to weblogic server instance running at t3://127.0.0.1:7001 as
username weblogic ...

Successfully connected to Admin Server 'myserver' that belongs to domain 'mydomain' is system output and should be formatted as code.

Now we can start playing with it. With WLST, the JMX tree can be traversed as a Unix filesystem, where the JMX MBeans are directories and its attributes are files. Keep in mind the Python syntax all the way through, and remember that WLST still doesn't recognize wildcards. That's the reason why we're going to omit most of the ls() output (see Listing 5).

We could have also gotten that far on a single cd('/JDBCConnectionPools/MyPool') command. WLST always remembers the cmo (Current Managed Object), the MBean corresponding to the current 'folder' we're browsing. So, these commands are equivalent from the practical point-of-view:

 


wls:/mydomain/config/JDBCConnectionPools/MyPool> cmo
[Caching Stub]Proxy for mydomain:Name=MyPool,Type=JDBCConnectionPool
wls:/mydomain/config/JDBCConnectionPools/MyPool> pwd()
'/JDBCConnectionPools/MyPool'

Now, let's change a couple of random properties (see Listing 6). Remember that Python doesn't have boolean attributes. The server can return true and false (since it runs Java), but you can't assign those values. Don't worry, though; if you check it through the WebLogic console, your boolean value of 1 has been interpreted correctly by the server.

You could have gotten the same result using the equivalent techniques shown in the section above about "Automating Server Configuration." I find this way easier for systems administrators, and the first way for developers preparing scripts. It just fits better in each different kind of toolset: system administrators are more used to Unix shells, and developers feel more comfortable with the "smell" of Java.

Managing the Server Configuration Example: A Real Case
It's common to need to peep inside those nasty JDBC calls. One sometimes really wants to be able to see the conversation between the WebLogic server and the database, and why in hell the query returns 0 rows, or profile performance, okay. Logging the JDBC calls (not just the SQL, please, but the parameters too) with a hot-plug capability should be nice. Wanna give it a try?

First, let's download the p6spy JDBC driver. It is a JDBC wrapper that will log anything that goes through it. To configure it, put the p6spy.jar and the directory containing the p6spy.properties in the server classpath (don't forget the directory, or WebLogic will complain as if the JAR file were not present). Tune the p6spy.properties to your needs.

What we want to achieve is the creation of two Connection Pools, one directly with Oracle JDBC driver and the other through p6spy. Then, we will change the datasource to point to the p6spy datasource without restarting the server (if we believe the Web console interface, this change does not need a reboot).

We will start by executing the administration script developed earlier:

 


wls:/(offline)> execfile('AdminTool.py')

Connecting to weblogic server instance running at t3://127.0.0.1:7001 as
username weblogic ...

Successfully connected to Admin Server 'myserver' that belongs to domain 'mydomain'. It also is system output and should be formatted accordingly.

We can create the Connection Pool now.

 


wls:/mydomain/config> admin.createPool("P6SPY Connection Pool",
"com.p6spy.engine.spy.P6SpyDriver")
JDBCConnectionPool with name 'P6SPY Connection Pool'
has been created successfully.

In the WebLogic console we can see the following (well, the WebLogic log line will only appear if you have the 'debug to console' option activated):

 


<28-feb-2005 20H18' GMT> <Info> <JDBC> <BEA-001132>
<Initialized statement cache of size "10"
for connection in pool "P6SPY Connection Pool".>
1109621928226|0|1|statement|SELECT 1 FROM DUAL|SELECT 1 FROM DUAL
1109621928242|0|1|statement|SELECT 1 FROM DUAL|SELECT 1 FROM DUAL

which shows the connection pool initializing and new connections test. We'll suppose that the dataSource doesn't exist yet. If we were clean, we would have foreseen it and created the method in our AdminTool class, but we can still do it via the interactive shell in Listing 7.

We have started directing the datasource to the P6SPY connection pool, so you can check your application and see that it really logs JDBC statements; try it with a test case. Now, there are two ways to disable the logging. Since we have the datasource in a Jython variable, we can do it the 'Java' way:

 


datasource.setPoolName(MY_POOL_NAME)

or, the 'system administrator' way shown in Listing 8.

Conclusion
WLST is an awesome tool capable of boosting your application server configuration and remote maintenance. It still lacks a find/locate option (for the not uncommon case where one needs to find a configuration option and can't recall its location) with wildcard support. But when it finally gets bundled with WebLogic 9 it's sure to be useful.

Resources

  • The p6spy open source driver: www.p6spy.com/
  • Download WLST online: http://dev2dev.bea.com/codelibrary/code/wlst.jsp
  • Download WLST offline: http://dev2dev.bea.com/codelibrary/code/wlst_offline.jsp
  • Strategies for WebLogic domain configuration: www.sys-con.com/story/?storyid=47096&DE=1
  • Martin Fowler on scripting languages for complex tasks not easily achieved with XML: http://martinfowler.com/bliki/BuildLanguage.html
  • More Stories By Ignacio Coloma

    Ignacio Coloma is a J2EE architect at InfoInnova. For the last six years he has been developing applications for e-banking, air transport, e-government, and message processing systems. Currently he is extending J2EE applications with scripting languages.

    Comments (1) View Comments

    Share your thoughts on this story.

    Add your comment
    You must be signed in to add a comment. Sign-in | Register

    In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


    Most Recent Comments
    [email protected] 10/03/08 09:23:49 AM EDT

    Good article.
    Couldn't find the listings though.
    Are they missing ?

    @ThingsExpo Stories
    SYS-CON Events announced today that Interoute, owner-operator of one of Europe's largest networks and a global cloud services platform, has been named “Bronze Sponsor” of SYS-CON's 20th Cloud Expo, which will take place on June 6-8, 2017 at the Javits Center in New York, New York. Interoute is the owner-operator of one of Europe's largest networks and a global cloud services platform which encompasses 12 data centers, 14 virtual data centers and 31 colocation centers, with connections to 195 add...
    SYS-CON Events announced today that Cloudistics, an on-premises cloud computing company, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Cloudistics delivers a complete public cloud experience with composable on-premises infrastructures to medium and large enterprises. Its software-defined technology natively converges network, storage, compute, virtualization, and management into a ...
    SYS-CON Events announced today that SD Times | BZ Media has been named “Media Sponsor” of SYS-CON's 20th International Cloud Expo, which will take place on June 6–8, 2017, at the Javits Center in New York City, NY. BZ Media LLC is a high-tech media company that produces technical conferences and expositions, and publishes a magazine, newsletters and websites in the software development, SharePoint, mobile development and commercial UAV markets.
    "I think that everyone recognizes that for IoT to really realize its full potential and value that it is about creating ecosystems and marketplaces and that no single vendor is able to support what is required," explained Esmeralda Swartz, VP, Marketing Enterprise and Cloud at Ericsson, in this SYS-CON.tv interview at @ThingsExpo, held June 7-9, 2016, at the Javits Center in New York City, NY.
    Why do your mobile transformations need to happen today? Mobile is the strategy that enterprise transformation centers on to drive customer engagement. In his general session at @ThingsExpo, Roger Woods, Director, Mobile Product & Strategy – Adobe Marketing Cloud, covered key IoT and mobile trends that are forcing mobile transformation, key components of a solid mobile strategy and explored how brands are effectively driving mobile change throughout the enterprise.
    My team embarked on building a data lake for our sales and marketing data to better understand customer journeys. This required building a hybrid data pipeline to connect our cloud CRM with the new Hadoop Data Lake. One challenge is that IT was not in a position to provide support until we proved value and marketing did not have the experience, so we embarked on the journey ourselves within the product marketing team for our line of business within Progress. In his session at @BigDataExpo, Sum...
    Keeping pace with advancements in software delivery processes and tooling is taxing even for the most proficient organizations. Point tools, platforms, open source and the increasing adoption of private and public cloud services requires strong engineering rigor - all in the face of developer demands to use the tools of choice. As Agile has settled in as a mainstream practice, now DevOps has emerged as the next wave to improve software delivery speed and output. To make DevOps work, organization...
    SYS-CON Events announced today that MobiDev, a client-oriented software development company, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. MobiDev is a software company that develops and delivers turn-key mobile apps, websites, web services, and complex softw...
    DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm.
    What sort of WebRTC based applications can we expect to see over the next year and beyond? One way to predict development trends is to see what sorts of applications startups are building. In his session at @ThingsExpo, Arin Sime, founder of WebRTC.ventures, will discuss the current and likely future trends in WebRTC application development based on real requests for custom applications from real customers, as well as other public sources of information,
    China Unicom exhibit at the 19th International Cloud Expo, which took place at the Santa Clara Convention Center in Santa Clara, CA, in November 2016. China United Network Communications Group Co. Ltd ("China Unicom") was officially established in 2009 on the basis of the merger of former China Netcom and former China Unicom. China Unicom mainly operates a full range of telecommunications services including mobile broadband (GSM, WCDMA, LTE FDD, TD-LTE), fixed-line broadband, ICT, data communica...
    SYS-CON Events announced today that Ocean9will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Ocean9 provides cloud services for Backup, Disaster Recovery (DRaaS) and instant Innovation, and redefines enterprise infrastructure with its cloud native subscription offerings for mission critical SAP workloads.
    Things are changing so quickly in IoT that it would take a wizard to predict which ecosystem will gain the most traction. In order for IoT to reach its potential, smart devices must be able to work together. Today, there are a slew of interoperability standards being promoted by big names to make this happen: HomeKit, Brillo and Alljoyn. In his session at @ThingsExpo, Adam Justice, vice president and general manager of Grid Connect, will review what happens when smart devices don’t work togethe...
    SYS-CON Events announced today that SoftLayer, an IBM Company, has been named “Gold Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. SoftLayer, an IBM Company, provides cloud infrastructure as a service from a growing number of data centers and network points of presence around the world. SoftLayer’s customers range from Web startups to global enterprises.
    SYS-CON Events announced today that Technologic Systems Inc., an embedded systems solutions company, will exhibit at SYS-CON's @ThingsExpo, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Technologic Systems is an embedded systems company with headquarters in Fountain Hills, Arizona. They have been in business for 32 years, helping more than 8,000 OEM customers and building over a hundred COTS products that have never been discontinued. Technologic Systems’ pr...
    SYS-CON Events announced today that Auditwerx will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Auditwerx specializes in SOC 1, SOC 2, and SOC 3 attestation services throughout the U.S. and Canada. As a division of Carr, Riggs & Ingram (CRI), one of the top 20 largest CPA firms nationally, you can expect the resources, skills, and experience of a much larger firm combined with the accessibility and attent...
    SYS-CON Events announced today that CA Technologies has been named “Platinum Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY, and the 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business – from apparel to energy – is being rewritten by software. From ...
    SYS-CON Events announced today that HTBase will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. HTBase (Gartner 2016 Cool Vendor) delivers a Composable IT infrastructure solution architected for agility and increased efficiency. It turns compute, storage, and fabric into fluid pools of resources that are easily composed and re-composed to meet each application’s needs. With HTBase, companies can quickly prov...
    SYS-CON Events announced today that Loom Systems will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Founded in 2015, Loom Systems delivers an advanced AI solution to predict and prevent problems in the digital business. Loom stands alone in the industry as an AI analysis platform requiring no prior math knowledge from operators, leveraging the existing staff to succeed in the digital era. With offices in S...
    Buzzword alert: Microservices and IoT at a DevOps conference? What could possibly go wrong? In this Power Panel at DevOps Summit, moderated by Jason Bloomberg, the leading expert on architecting agility for the enterprise and president of Intellyx, panelists peeled away the buzz and discuss the important architectural principles behind implementing IoT solutions for the enterprise. As remote IoT devices and sensors become increasingly intelligent, they become part of our distributed cloud enviro...