Welcome!

Weblogic Authors: Yeshim Deniz, 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
    DX World EXPO, LLC, a Lighthouse Point, Florida-based startup trade show producer and the creator of "DXWorldEXPO® - Digital Transformation Conference & Expo" has announced its executive management team. The team is headed by Levent Selamoglu, who has been named CEO. "Now is the time for a truly global DX event, to bring together the leading minds from the technology world in a conversation about Digital Transformation," he said in making the announcement.
    "Space Monkey by Vivent Smart Home is a product that is a distributed cloud-based edge storage network. Vivent Smart Home, our parent company, is a smart home provider that places a lot of hard drives across homes in North America," explained JT Olds, Director of Engineering, and Brandon Crowfeather, Product Manager, at Vivint Smart Home, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    SYS-CON Events announced today that Conference Guru has been named “Media Sponsor” of the 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. A valuable conference experience generates new contacts, sales leads, potential strategic partners and potential investors; helps gather competitive intelligence and even provides inspiration for new products and services. Conference Guru works with conference organizers to pass great deals to gre...
    The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develop...
    In his Opening Keynote at 21st Cloud Expo, John Considine, General Manager of IBM Cloud Infrastructure, led attendees through the exciting evolution of the cloud. He looked at this major disruption from the perspective of technology, business models, and what this means for enterprises of all sizes. John Considine is General Manager of Cloud Infrastructure Services at IBM. In that role he is responsible for leading IBM’s public cloud infrastructure including strategy, development, and offering m...
    "Evatronix provides design services to companies that need to integrate the IoT technology in their products but they don't necessarily have the expertise, knowledge and design team to do so," explained Adam Morawiec, VP of Business Development at Evatronix, in this SYS-CON.tv interview at @ThingsExpo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    To get the most out of their data, successful companies are not focusing on queries and data lakes, they are actively integrating analytics into their operations with a data-first application development approach. Real-time adjustments to improve revenues, reduce costs, or mitigate risk rely on applications that minimize latency on a variety of data sources. In his session at @BigDataExpo, Jack Norris, Senior Vice President, Data and Applications at MapR Technologies, reviewed best practices to ...
    Widespread fragmentation is stalling the growth of the IIoT and making it difficult for partners to work together. The number of software platforms, apps, hardware and connectivity standards is creating paralysis among businesses that are afraid of being locked into a solution. EdgeX Foundry is unifying the community around a common IoT edge framework and an ecosystem of interoperable components.
    Large industrial manufacturing organizations are adopting the agile principles of cloud software companies. The industrial manufacturing development process has not scaled over time. Now that design CAD teams are geographically distributed, centralizing their work is key. With large multi-gigabyte projects, outdated tools have stifled industrial team agility, time-to-market milestones, and impacted P&L stakeholders.
    "Akvelon is a software development company and we also provide consultancy services to folks who are looking to scale or accelerate their engineering roadmaps," explained Jeremiah Mothersell, Marketing Manager at Akvelon, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    "IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
    In his session at 21st Cloud Expo, Carl J. Levine, Senior Technical Evangelist for NS1, will objectively discuss how DNS is used to solve Digital Transformation challenges in large SaaS applications, CDNs, AdTech platforms, and other demanding use cases. Carl J. Levine is the Senior Technical Evangelist for NS1. A veteran of the Internet Infrastructure space, he has over a decade of experience with startups, networking protocols and Internet infrastructure, combined with the unique ability to it...
    22nd International Cloud Expo, taking place June 5-7, 2018, at the Javits Center in New York City, NY, and co-located with the 1st DXWorld Expo will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud ...
    "Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
    Gemini is Yahoo’s native and search advertising platform. To ensure the quality of a complex distributed system that spans multiple products and components and across various desktop websites and mobile app and web experiences – both Yahoo owned and operated and third-party syndication (supply), with complex interaction with more than a billion users and numerous advertisers globally (demand) – it becomes imperative to automate a set of end-to-end tests 24x7 to detect bugs and regression. In th...
    "MobiDev is a software development company and we do complex, custom software development for everybody from entrepreneurs to large enterprises," explained Alan Winters, U.S. Head of Business Development at MobiDev, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
    "There's plenty of bandwidth out there but it's never in the right place. So what Cedexis does is uses data to work out the best pathways to get data from the origin to the person who wants to get it," explained Simon Jones, Evangelist and Head of Marketing at Cedexis, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
    SYS-CON Events announced today that CrowdReviews.com has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5–7, 2018, at the Javits Center in New York City, NY. CrowdReviews.com is a transparent online platform for determining which products and services are the best based on the opinion of the crowd. The crowd consists of Internet users that have experienced products and services first-hand and have an interest in letting other potential buye...
    SYS-CON Events announced today that Telecom Reseller has been named “Media Sponsor” of SYS-CON's 22nd International Cloud Expo, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.