Riena/Getting Started with Client Monitoring
We know now that in the early years of the twentieth century this world was being watched closely by intelligences greater than man's, and yet as mortal as his own. We know now that as human beings busied themselves about their various concerns they were scrutinized and studied, perhaps almost as narrowly as a man with a microscope might scrutinize the transient creatures that swarm and multiply in a drop of water. With infinite complacence people went to and fro over the earth about their little affairs, serene in the assurance of their dominion over this small, spinning fragment of solar driftwood which, by chance or design, man has inherited out of the dark mystery of Time and Space. Yet across an immense ethereal gulf, minds that are to our minds as ours are to the beasts in the jungle, intellects vast, cool and unsympathetic, regarded this earth with envious eyes and slowly and surely drew their plans against us. ...
- Orson Welles, 1938, from the original script of the radio adaption of "War of the Worlds" by H.G. Wells
Oh, no, stop! No, that's of course NOT the intent of Client Monitoring.
The problem that we want to help solving with Client Monitoring is to automatically provide the operators of business applications with measurements about the health and/or usage of a system. With this information a system can be optimized (e.g. bugs fixed, user interface improved, etc.) before the user of the system stumbles upon these issues.
Furthermore the automatically provided information can be much more precise than bug reports entered by the user - can because the developers of the application are now responsible for providing the necessary information, not the user. Remember the targeted user of a Riena application is not a developer.
Possible kinds of measurements:
- logging data, e.g. certain events produced by Eclipse's LogService
- usage data
- more technical, e.g. bundle state change
- user interface usage tracking
- tracking of application function usage
The Client Monitoring requires two bundles:
- containing classes and interfaces that are common to both client and server side of the application. This is a necessity when using Riena's communication
- containing the aliens - ehm - no, the workhorses
The structure of Client Monitoring is quite simple. There are a bunch of collectors gathering the required information and passing them to the aggregator. The aggregator puts this information in a store and activates the sender. The sender transmits the information to the receiver which is usually a Riena remote service. Activation of the sender is usually triggered by the collectors but can also triggered by any other component.
Collectors gather the information that should be transferred to the server. They have to either implement the interface
org.eclipse.riena.monitor.client.ICollector or extend
org.eclipse.riena.monitor.client.AbstractCollector - extending the
AbstractCollector is easier. There are already a few ready-to-use collectors, e.g the
LogServiceCollector. All collectors have to be defined with the extension point
LogServiceCollector listens to log service events and records them. It has to be defined with something like that:
<extension point="org.eclipse.riena.monitor.collectors"> <collector category="LogCollector" maxItems="50" class="org.eclipse.riena.monitor.client.LogServiceCollector: collectRange=1..3; triggerRange=1, 2; async=false"> </collector> </extension>
category gives the collector a unique name. This is because the same class implementing a collector can be used for different purposes. The attribute
maxItems defines the maximum number of logged items that shall be kept within the local store. The attribute
class defines the collector class and contains additional configuration settings. These settings are collector-specific.
In the example above there are two parameters
collectRange (or filterClass see below) and
triggerRange. Both parameters are of type range. A range defines a set of integers (see
- is a interval containing 1, 2 and 3
- are simply the values 1 and 2
- is a interval containing 1, 2, 3, 5 and 7
These integers are the log levels defined by
org.osgi.service.log.LogService. So, for the above defined
LogServiceCollector this means collect (collectRange) all logs that are INFO (3), WARNING (2) or ERROR (1) and trigger transmission (triggerRange) on WARNING (2) or ERROR (1).
The optional parameter
async allows to attach the
LogServiceCollector either synchronously or asynchronously. The default is asynchronously. The advantage of attaching synchronously is that the
LogServiceCollector can access thread information.
With the configuration capabilities of the
LogServiceCollector it also possible to define another collector that listens to custom log levels, i.e. application-specific log levels, e.g.
<extension point="org.eclipse.riena.monitor.collectors"> <collector category="CustomCollector" maxItems="250" class="org.eclipse.riena.monitor.client.LogServiceCollector: collectRange=-2..0; triggerRange=-2"> </collector> </extension>
The filtering possibilities with the collectRange are very limited. If a more fine grained filtering is required it is possible to define a filter, e.g.
<extension point="org.eclipse.riena.monitor.collectors"> <collector category="LogCollector" maxItems="50" class="org.eclipse.riena.monitor.client.LogServiceCollector: triggerRange=1, 2; async=false; filterClass=org.eclipse.riena.example.client.monitor.LogServiceCollectorFilter"> </collector> </extension>
The filterClass attribute defines a class implementing ILogServiceCollectorFilter. If this attribute is given the collectRange is no longer required. However, it can still be used and it is evaluated before the filter.
org.eclipse.riena.internal.monitor.client.Aggregator is implemented as an OSGi service and responsible for
- the configuration of the client monitoring, e.g. evaluating the extensions (collector, store and sender)
- life cycle
- aggregating all the information from the collectors
- and delegating tasks to the store and the sender
The aggregator is not meant to be replaced by custom implementations.
There is already a simple store implementation
org.eclipse.riena.internal.monitor.client.SimpleStore that stores the collected items within compressed and encrypted files.
This simple store gets configured with:
<extension point="org.eclipse.riena.monitor.store"> <store name="SimpleStore" class="org.eclipse.riena.monitor.client.SimpleStore:cleanupDelay=1 h"> </store> </extension>
This simple store performs cleanups (i.e. removable of transmitted items) within given periods defined by the
cleanupDelay property. This period is defined with a simple syntax that does not allow fractions but allows to use time units, e.g.
1 h 30 m 20 s 3 ms.
It is of course possible to define another store implementation with this extension point. The store just has to implement
Same as with the store, there is also a simple sender implementation
org.eclipse.riena.monitor.client.SimpleSender. This implementation expects that an OSGi service for the interface
org.eclipse.riena.monitor.common.IReceiver exists. This service is then used for transferring the items to the receiver. Within Riena the receiver is usually a server component and the service is a remote service that has been made accessible with Riena communications (see Riena Remote Services for how to do that).
The sender has to be configured like this:
<extension point="org.eclipse.riena.monitor.sender"> <sender name="SimpleSender" class="org.eclipse.riena.monitor.client.SimpleSender:retryTime=20 m"> </sender> </extension>
The simple sender can be configured with a
retryTime property. This time specifies the duration between retries when sending has failed. The syntax for the
retryTime is the same as for the
cleanupDelay of the store.
The receiver is usually a server component that is exposed to the client as a Riena remote service. There is no ready-to-use simple receiver (yet), because it is too dependent on the customer's individual use case. I.e. what should happen with the transmitted items? Should they be stored in a database or in the file system? Should administrators be notified when certain patterns occur? And, and, and ...To register the receiver on the client you need something like that:
Register.remoteProxy(IReceiver.class) .usingUrl("http://localhost:8080/hessian/CollectibleReceiverWS") .withProtocol("hessian") .andStart(context);
IReceiver monitoringReceiver = new SimpleMonitoringReceiver();
context.registerService(IReceiver.class.getName(), monitoringReceiver, null); Publish.service(IReceiver.class) .usingPath("/CollectibleReceiverWS") .withProtocol("hessian").andStart(context);
Client information provider
Sometimes it is useful to know more about the creator of the collected information, e.g. its host name or IP address. To provide the client monitoring with this information it is necessary to define a
org.eclipse.riena.monitor.client.IClientInfoProvider which does exactly that. The information gathered from that provider enriches the collected data and will be transferred to the server along with it.
org.eclipse.riena.monitor.client.SimpleClientInfoProvider, which is capable of gathering Java system properties plus a few more special properties. You need to define something like this:
<extension point="org.eclipse.riena.monitor.clientinfoprovider"> <clientInfoProvider name="SimpleClientInfoProvider" class="org.eclipse.riena.monitor.client.SimpleClientInfoProvider:user.name,x-host.name"> </clientInfoProvider> </extension>
InetAddress.getLocalHost().getHostName(). This results into a client information like this: user.name=sliebig,x-host.name=pc4723489
Currently there are three synthetic properties:
- retrieves the host's ip address as given by
- retrieves the host's name as given by
- retrieves the host's canonical name as given by
And of course it's possible to write your own
Integrating client monitoring is simple:
- add the common bundle to both the client and the server
- configure the collectors, the store, the sender and maybe an client information provider on the client
- create a receiver on the server and register it as a remote service on the client