Database Reference
In-Depth Information
While custom management UI is the most complex area of Extensibility, the documentation is not very clear, and it's
difficult to draw the line between metadata-based UI and Flex-based. Thus, learning by example will help you a lot.
I've also found that searching for a generic Adobe Flex solution such as charts attributes lets me guess some of the
XML attributes for metadata-based UI that I was not able to find in the EM12c Extensibility documentation or EDK.
Metadata Registration Service
During development of the plug-in, you might have to do many iterative adjustments and verify the impact in the
EM12c console after each change. Packaging, deploying, and upgrading a plug-in with each small change can be
daunting. To reduce this deployment overhead, EM12c provides the Metadata Registration Service (MRS) via the
emctl register oms metadata
command to selectively upload and upgrade specific metadata. MRS is documented
in Section 13.7 of the
Extensibility Programmer's Reference
, but at the time of this writing the documentation coverage
is spotty.
From my experience, MRS works well for updating definitions of reports on the fly, updating user interface
definitions (
mpcui
service), and ECM metadata (
LiveSnapshotRegistration
service). However, registering new target
type metadata didn't always succeed for me, possibly because target metadata didn't propagate successfully to the
agent.
For example, to update or register a new report definition, you can use the following command:
emctl register oms metadata -service report -file report_file.xml -pluginId oracle.samples.xsh1
Note that some services require special steps when registering components. For example, registration of the
compliance standards service via MRS must be followed by manual execution of the
EM_COMPLIANCE_UTIL.trigger_rule_dependency_job
procedure in the repository database.
MRS also lets you implement some new features—for example, new job types and compliance standards with
existing targets—without actually developing any new plug-ins at all. In fact, although most of the time you create
plug-ins to package new target types, you can also create plug-ins without any target types and package, for example,
just reports or compliance standards.
Summary
In this chapter, you have become familiar with Metric Extensions and most of their features. You learned that while
EM12c metric extensions are much more flexible and manageable than Grid Control 10g/11g user-defined metrics,
they still lack many features that are essential for collecting metrics from multiple new targets and even existing ones.
For example, you can't easily process cumulative counters, create parameterized metric extensions, or use additional
collection mechanisms. Later, you also learned that metric extensions are built on top of the EM12c Extensibility
framework and are basically converted to similar XML definitions that you create when developing new target types.
In the second part of the chapter, you learned how to set up an environment for plug-in development, where to
find documentation and samples, and how to build and deploy those samples. Based on those sample plug-ins, you
learned all the basics of plug-in development and some tricks to make your life easier and your plug-in development
more efficient. You also drilled into the details of some useful advanced features such as configuration management
and learned where to look for sample implementation and documentation.
This chapter has emphasized that many sources are available for learning more about Extensibility and
plug-ins—whether using official documentation, XML Schema documentation, or even drilling into Oracle's
supplied plug-ins to understand how certain features work. Even if you don't expect to develop plug-ins either
for your own use or for distributing externally, the knowledge of the EM12c Extensibility framework should
deepen your understanding of EM12c internals, make you a better troubleshooter, and help you find answers
to questions even if they're not documented by Oracle. EM12c is there to make you more efficient in managing
enterprise infrastructures, and you can automate more tasks and cover a broader IT infrastructure footprint by
leveraging the Extensibility framework one way or another.
